RF Technology 1UTR800CN UHF BASE STATION User Manual R800 Manual

RF Technology Pty Ltd UHF BASE STATION R800 Manual

Users Manual

Eclipse SeriesRF Technologyrfinfo@rftechnology.com.auSeptember 2003 Revision 2T800 TransmitterOperation and Maintainance ManualThis manual is produced by RF Technology Pty Ltd10/8 Leighton Place, Hornsby NSW 2077 AustraliaCopyright © 1997, 1998, 2003 RF Technology
___________________________________________________________________________RF Technology T800 Page 2CONTENTS CONTENTS1. Operating Instructions 51.1 Front Panel controls and Indicators 51.1.1 PTT 51.1.2 Line 51.1.3 PWR LED 51.1.4 TX LED 51.1.5 ALARM LED 61.1.6 ALC LED 61.1.7 REF LED 61.1.8 TEST MIC 62. Transmitter Internal Jumper Options 72.1 JP2: EPROM Type 72.2 JP3: Dc Loop PTT 72.3 JP4: Audio Input source 72.4 JP5: 600 ¿ Termination 72.5 JP6: Input Level Attenuation82.6 JP7: Audio Frequency Response 82.7 JP8:Subaudible Tone Source82.8 JP9, JP10, JP11 dc Loop PTT Input Configuration JP3 (1-2) 82.9 JP16: Direct Digital Input (Rev 4 or Higher) 82.10 JP17: Bypass Low Pass Filter (Rev 4 or Higher)92.11 JP19: Alarm Output (Rev 4 or Higher) 92.12 JP22: Use Tone- as a Direct Digital Input (Rev 4 or Higher) 92.13 JP23: Connection of DMTX Board (Rev 4 or Higher) 93. Transmitter Internal Jumper Options3.1 25 Pin Connector 103.2 Rear Panel Connectors 114. Channel and Tone Frequency Programming 125. Circuit Description 135.1 VCO Section 135.2 PLL Section 135.3 Power Amplifier 145.4 Temperature Protection 145.5 600 ¿ Line Input 145.6 Direct coupled Audio Input 145.7 Local Microphone Input 155.8 CTCSS and Tone Filter 155.9 Audio Signal Processing 155.10 PTT and DC Remote Control 165.11 Microprocessor Controller 165.12 Voltage Regulator 176. Field Alignment Procedure 176.1 Standard Test Conditions 186.2VCO Alignment186.3 TCXO Calibration 186.4 Modulation Balance 19
___________________________________________________________________________RF Technology T800 Page 3CONTENTS CONTENTS6.5 Tone Deviation 196.6 Deviation 206.7 Line Input Level 206.8 Output Power 207Specifications 217.1 Overall Description 217.1.1 Channel Capacity 217.1.2 CTCSS 217.1.3 Channel Programming 217.1.4 Channel Selection 217.1.5 Microprocessor 217.2 Physical Configuration 227.3 Front Panel Controls, Indicators and Test Points 227.3.1 Controls 227.3.2 Indicators 227.3.3 Test Points 227.4 Electrical Specifications 227.4.1 Power Requirements 227.4.2 Frequency Range and Channel Spacing 237.4.3 Frequency Synthesizer Step Size 237.4.4 Frequency Stability 237.4.5 Number of Channels 237.4.6 Antenna Impedance 237.4.7 Output Power 237.4.8Transmit Duty Cycle237.4.9 Spurious and Harmonics 237.4.10 Carrier and Modulation Attack Time 237.4.11 Modulation 237.4.12 Distortion 247.4.13 Residual Modulation and Noise 247.4.14600¿ Line Input Sensitivity247.4.15 HI-Z Input 247.4.16 Test Microphone Input 247.4.17 External Tone Input 247.4.18 External ALC Input 247.4.19 T/R Relay Driver 247.4.20 Channel Select Input/Output 247.4.21 DC Remote Keying 257.4.22 Programmable No-Tone Period 257.4.23 Firmware Timers 257.4.24 CTCSS 257.5 Connectors 257.5.1 Antenna Connector 257.5.2 Power and I/O Connector 277.5.3 Test Connector 27
___________________________________________________________________________RF Technology T800 Page 4CONTENTS CONTENTSAEngineering DiagramsA1 Block DiagramA2 Circuit DiagramA3 Component Overlay DiagramBParts List
___________________________________________________________________________RF Technology T800 Page 51 OPERATING INSTRUCTIONS WARNINGChanges or modifications not expressly approved byRF Technology could void your authority to operate thisequipment. Specifications may vary from those given inthis document in accordance with requirements of localauthorities. RF Technology equipment is subject tocontinual improvement and RF Technology reserves theright to change performance and specification withoutfurther notice.1Operating Instructions1.1 Front Panel Controls and Indicators1.1.1 PTTA front-panel push-to-talk (PTT) button is provided to facilitate bench and field tests andadjustments. The button is a momentary action type. When keyed, audio from the line inputis disabled so that a carrier with sub-tone is transmitted. The front-panel microphone input isnot enabled in this mode, but it is enabled when the PTT line on that socket is pulled toground.1.1.2 LineThe LINE trimpot is accessible by means of a small screwdriver from the front panel of themodule. It is used to set the correct sensitivity of the line and direct audio inputs. It isfactory preset to give 60% of rated deviation with an input of 0dBm (1mW on 600Ωequivalent to 775mV RMS or about 2.2V peak-to-peak) at 1kHz. The nominal 60% deviationlevel may be adjusted by measuring between pins 6 and 1 on the test socket, and adjusting thepot. By this means an input sensitivity from approximately -30dBm to +10dBm may beestablished.An internal jumper provides a coarse adjustment step of 20dB. Between the jumper and thetrimpot, a wide range of input levels may be accommodated.1.1.3 POWER LEDThe PWR LED shows that the dc supply is connected to the receiver.1.1.4 TX LEDThe TX LED illuminates when the transmitter is keyed. It will not illuminate (and an Alarmcadence will be shown) if the synthesizer becomes unlocked, or the output amplifier supply isinterrupted by the microprocessor.
___________________________________________________________________________RF Technology T800 Page 61.1.5 Alarm LED 1 OPERATING INSTRUCTIONS1.1.5 ALARM LEDThe Alarm LED can indicate several fault conditions if they are detected by the self testprogram. The alarm indicator shows the highest priority fault present. Receivers usingsoftware issue 5 and higher use the cadence of the LED flash sequence to indicate the alarmcondition. Refer to table 1. Receivers using software issue 4 and lower use the LED flashrate to indicate the alarm condition. Refer to table 2.LED Flash Cadence Fault Condition5 flashes, pause Synthesizer unlocked4 flashes, pause Tuning voltage out of range3 flashes, pause Low forward power2 flashes, pause High reverse (reflected) power1 flash, pause Low dc supply voltageLED ON continuouslyTransmitter timed out Table 1: Interpretations of LED flash cadenceIndication Fault ConditionFlashing, 8 per second Synthesizer unlockedFlashing, 4 per second Tuning voltage outside correct rangeFlashing, 2 per second Low forward powerFlashing, 1 per second High reverse powerContinuous dc supply voltage low or highTable 2: Interpretations of LED flash speed, for early models1.1.6 ALC LEDThe ALC LED indicates that the transmitter output power is being controlled by an externalamplifier through the external ALC input.1.1.7 REF LEDThe REF LED indicates that the synthesizer frequency reference is locked to an externalreference.1.1.8 TEST MIC.The TEST MIC. DIN socket is provided for use with a standard mobile or handset 200 Ohmdynamic microphone. The external audio inputs are disabled when the TEST MIC’S PTT ison.
___________________________________________________________________________RF Technology T800 Page 72TRANSMITTER INTERNAL JUMPER OPTIONS2Transmitter Internal Jumper OptionsIn the following subsections an asterisk (*) signifies the standard (Ex-Factory) configurationof a jumper.2.1 JP2: EPROM TypeCondition Position27C256 2-3 *27C64 1-22.2 JP3: 600 Ohm Line Dc Loop PTT InputBy default, Eclipse exciters can be keyed up by pulling the PTT signal low, or by dc loopsignalling on the audio pair.This jumper enables or disables this second method.Condition Positiondc loop connected (enabled) 1-2 *dc loop not connected (bypassed) 2-32.3 JP4: Audio Input Source SelectionEither the 600Ω or the high-Z balanced inputs may be selected.Condition Position600Ω Input 2-3 *High-impedance Input 1-22.4 JP5: 600 ¿ TerminationNormally the Line Input is terminated in 600 ¿ . The 600 ohm termination can be removedby choosing the alternate position.Condition Position600¿ Termination 1-2*No Termination 2-3
___________________________________________________________________________RF Technology T800 Page 82.5 JP6: Input Level Attenuation 2 TRANSMITTER JUMPER OPTIONS2.5 JP6: Input Level AttenuationThis jumper permits coarse input sensitivity to be set. In the default position, the unit expectsa line level of 0dBm (nominal) at its Line Input. In the alternate position, levels of+20dBm(nominal) can be accepted.Condition Position0dB attenuation 1-2 *20dB attenuation 2-32.6 JP7: Audio Frequency ResponseCondition Position750 uSec. Pre-emphasis 1-2 *Flat Response 2-32.7 JP8: Sub-audible Tone SourceCondition PositionInternal CTCSS 1-2, 4-5 *External input 2-3, 5-62.8 JP9/10/11: dc Loop ConfigurationDc loop current on the audio pair is normally sourced externally. The Eclipse exciters loopthe current through an opto-isolator. When the current flows the exciter keys up.An alternative arrangement is possible. The exciters can source the current and an externaldevice can provide the dc loop.These three jumpers select the appropriate mode.Condition JP9 JP10 JP11Current Loop Input ON OFF OFF *12Vdc Loop source OFF ON ON2.9 JP16: Direct Digital Input (Rev 4 or Higher)Some trunking controllers have digital encoding schemes which operate to very lowfrequencies. The elliptical filter, used as a 250Hz low pass filter in the tone section, can
___________________________________________________________________________RF Technology T800 Page 92 TRANSMITTER INTERNAL JUMPER OPTIONS 2.10 JP17: Bypass Low Pass Filtercause excessive pulse edge distortion of the trunking controller’s digital signals. In suchcircumstances, JP16 allows a user to bypass the low and high pass filters in the tone inputsection. See also 2.12 - JP22: If direct tone input is selected, then JP22 should be removed(open)Condition PositionNormal Tone Input 1-2*Direct Tone Input 2-32.10 JP17: Bypass Low Pass Filter (Rev 4 or higher)Some trunking controllers have digital encoding schemes that require the low pass filter in thetone input section to be bypassed. JP17 allows this. Normally JP17 is open circuit. Placinga link across it will bypass the low pass filter.In conjunction with this change, it sometimes may be necessary, depending on the type oftrunking controller used, to add a 100K resistor in the place reserved for R157.2.11 JP19: Alarm Output (Rev 4 or higher)The main audio transformer (T1), is connected to the Line IP1 and Line IP4 pins on P3.These two pins constitute the main audio input for the exciter. The centre taps of the audiotransformer, though, are brought out on Line IP2, and Line IP3. These can be used asalternate audio pins for larger signals, or to directly access the dc loop sense circuitry. JP19allows an alternate use for Line IP2 (pin 7 of P3). In the alternate position for JP19, theALARM signal (the signal that drives the ALARM LED itself) is connected to pin 7 of P3.The ALARM signal when asserted is low active; when unasserted, it pulls high to +9.4Vthrough an LED and a 680 ohm resistor.Condition PositionP3, pin 7 connects to center tap of transformer T1 1-2*P3, pin 7 connects to ALARM signal 2-32.12 JP22: Use Tone- as a Direct Digital Input (Rev 4 or higher)JP22 is normally shunted with a jumper, which connects Tone- on P3 (pin 18), as the negative leg of theTone input pair. Removing this jumper disconnects Tone- from this path and allows the use of theTone- pin to be used as a direct digital input. See also 2.9 - JP16: If this jumper is removed, then JP16should be in the alternative position (Direct Tone Input).2.13 JP23: Connection of DMTX Board (Rev 4 or higher)When a DMTX board is connected to an exciter, there is provision for digital or audio modulation of thereference osciallator and the VCO. The digital signal is input via the DB9 rear connector and the audioinput signal is via the Line inputs on the standard DB25 rear panel connector.
___________________________________________________________________________RF Technology T800 Page 103.1 25 Pin Connector 3 TRANSMITTER I/O CONNECTIONSCondition PositionNo DMTX board 1-2, 5-6*DMTX board connected 2-3, 4-5In addition to the jumper changes, a wire link or zero ohm resistor must be connected in theplace marked for R159.3Transmitter I/O Connections3.1 25 Pin ConnectorThe D-shell 25 pin connector is the main interface to the transmitter. The pin connections aredescribed in table 3.Function Signal Pins SpecificationDC power +12 Vdc 0 Vdc 1, 1413, 25 +11.4 to 16 Vdc GroundChannel Select 124810204080219221023112412BCD Coded0 = Open Circuitor 0 Vdc1 = +5 to +16 VdcRS232 Data InOut 152Test and Programming use9600, 8 data 2 stop bits600Ω Line HighLow 206Transformer IsolatedBalanced 0dBm Output150Ω / Hybrid 719Direct PTT input 3Ground to key PTTT/R Relay driver output 16 Open collector,250mA/30VSub-Audible Tone Input [+] 5>10kΩ, AC coupled[-] 18 (1-250Hz)High-Z Audio Input [+] 4>10kΩ, AC coupled[-] 17 (10Hz-3kHz)External ALC input 8 <0.5V/1mA to obtain>30dB attenuation, O/Cfor maximum powerTable 3: Pin connections and explanations for the main 25-pin, D connector.
___________________________________________________________________________RF Technology T800 Page 113 TRANSMITTER I/O CONNECTIONS 3.2 Rear Panel Connectors3.2 Rear Panel ConnectorsThe exciter and receiver can be supplied with optional rear panel connectors that bringout the more important signals available on P1, the rear panel DB25 connector.Figures 1 and 2 show the rear panel connectors, and Table 4 shows the signals that are broughtout to the spade connectors. The spade connectors (2.1x0.6x7mm) are captive/solderedat the labelled points. Fig 1 Fig 2 RX PCB TX PCB The Receiver and Transmitter modules plug into the back plane DB25/F connectors To configure: Solder wire connections between appropriate points.
___________________________________________________________________________RF Technology T800 Page 12 4 CHANNEL and TONE FREQUENCY PROGRAMMINGReceiverDB25/F RXPCB DESCRIPTION TXPCB TransmitterDB25/F1, 14 +12V +12V DC SUPPLY +12V 1, 142TXD TX Data TXD 215 RXD RX Data RXD 153COR+ Carrier Operate Sw+ PressToTalk input PTT 316 COR- Carrier Operate Sw- Tx/Rx output T/R 164TONE Subtone output Hi Z audio input+ AUD+ 417 AUDIO Audio output Hi Z audio input- AUD- 175AGND Audio Ground Ext tone input+ TONE+ 518 DISC Discriminator output Ext tone input- TONE- 186LINE+ Line output+ Line input+ LINE+ 620 LINE- Line output- Line input- LINE- 208EXT SQ Ext Squelch input Auto Level Control ALC 813, 25 GND Ground, 0V GND 13, 2521 BCD 1 Channel select 1’s digit BCD 1 219BCD 2 Channel select 1’s digit BCD 2 922 BCD 4 Channel select 1’s digit BCD 4 2210 BCD 8 Channel select 1’s digit BCD 8 1023 BCD 10 Channel select 10’s digit BCD 10 2311 BCD 20 Channel select 10’s digit BCD 20 1124 BCD 40 Channel select 10’s digit BCD 40 2412 BCD 80 Channel select 10’s digit BCD 80 124Channel and Tone Frequency ProgrammingChannel and tone frequency programming is most easily accomplished with RF TechnologyTecHelp software or the Service Monitor 2000 software. This software can be run on an IBMcompatible PC and provides a number of additional useful facilities. DOS and 32-bit versionsare available.TecHelp allows setting of the adaptive noise squelch threshold, provides a simple means ofcalibrating the forward and reverse power detectors, setting the power alarm preset levels, andenabling transmitter hang time and timeout time limits. TecHelp can be supplied by yourdealer, distributor or by contacting RF Technology directly.
___________________________________________________________________________RF Technology T800 Page 135 CIRCUIT DESCRIPTION 5.1 VCO Section5Circuit DescriptionThe following descriptions should be read as an aid to understanding the block and schematicdiagrams given in the appendix of this manual.5.1 VCO SectionThe Voltage Controlled Oscillator uses a bipolar junction FET Q19 which oscillates at therequired transmitter output frequency. Varactor diodes D25 and D26 are used by the PLLcircuit to keep the oscillator on the desired frequency. A second varactor diode D3 is used tofrequency modulate the VCO. Transistor Q20 is used as an active filter to reduce the noiseon the oscillator supply voltage.The VCO is keyed ON by the microcontroller through Q10. It is keyed ON when any of thePTT inputs are active and OFF at all other times.The VCO output is amplified and buffered by monolithic amplifiers MA2 and MA3 beforebeing fed to the PLL IC U6.Amplifiers MA1, MA4 and MA5 increase the VCO output to approximately 10 mW to drivethe power amplifier. MA1 is not switched on until the PLL has locked and had time to settle.This prevents any momentary off channel transmission when the transmitter is keyed.5.2 PLL SectionThe frequency reference for the synthesiser is a crystal oscillator using transistors Q26 andQ27 and crystal Y3. The temperature stability is better than 5 ppm and it can be synchronisedto an external reference for improved stability. External reference option board 11/9119 isrequired when using an external reference.A positive temperature coefficient thermistor, XH1, is used in versions intended for operationdown to -30 degrees Celsius. The thermistor heats the crystal's case to maintain itstemperature above -10 degrees thus extending the oscillator stability of 5 ppm down to -30degrees ambient.Varactor diodes D27-30 are used to frequency modulate the oscillator. The processed transmitaudio signal from U7b varies the diodes bias voltage to modulate the reference frequency.This extends the modulation capability down to a few Hz for sub-audible tones and digitalsquelch codes. A two point modulation scheme is used with the audio also being fed to theVCO to modulate the higher audio frequencies.The 12.8 MHz output of Q27 is amplified by Q28 and Q29 to drive the reference input of thePLL synthesiser IC U6. This IC is a single chip synthesiser which includes a 1.1 GHz pre-scaler, programmable divider, reference divider and phase/frequency detector. The frequencydata for U6 is supplied via a serial data link by the microcontroller.
___________________________________________________________________________RF Technology T800 Page 145.3 Power Amplifier 5 CIRCUIT DESCRIPTIONThe phase detector output signals of U6 are used to control two switched current sources. Theoutput of the positive and negative sources Q3 and Q6, produce the tuning voltage which issmoothed by the loop filter components to bias the V.C.O. varactor diode D3.5.3 Power AmplifierThe 10 mW output from the main board connects to the power amplifier board through a shortminiature 50Ω coaxial cable.Q2 on the power amplifier board increases the signal to approximately200mW. The bias ofQ2 is controlled by Q1 and the power leveling circuitry to adjust the drive to the outputmodule U2.U2 increases the power from the driver to 30 watts before it is fed to the directional coupler,low pass filter and output connector. The directional coupler detects the forward and reversepower components and provides proportional dc voltages which are amplified by U1a andU1b.The forward power voltage from U1a and U1b are compared to the present DC referencevoltage from RV1. The difference is amplified by U1c, Q3 and Q4. The resulting controlvoltage supplies Q2 through R10, R12 and completes the power levelling control loop.5.4 Temperature ProtectionThermistor RT1 on the power amplifier board is used to sense the case temperature of theoutput module U2. If the case temperature rises above 90 degrees C, the voltage across RT1will increase and transistor Q5 will be turned on. This reduces the dc reference voltage to thepower regulator which inturn reduces the outpower by 6-10dB.5.5 600Ω Line InputThe 600Ω balanced line input connects to line isolation transformer T1. T1 has two 150Ωprimary windings which are normally connected in series for 600Ω lines. The dual primarywindings can be used to provide DC loop PTT signaling or a 2/4 wire hybrid connection. Allfour leads are available at the rear panel system connector.The secondary of T1 can be terminated with an internal 600Ω load through JP5 or left un-terminated in high impedance applications.5.6 Direct Coupled Audio InputA high impedance (10kΩ) direct AC coupled input is available at the system connector. Thedirect coupled input connects to U9a which is configured as a unity gain bridge amplifier.The bridge configuration allows audio signal inversion by interchanging the positive andnegative inputs and minimizes ground loop problems. Both inputs should be connected, withone lead going to the source output pin and the other connected to the source audio ground.
___________________________________________________________________________RF Technology T800 Page 155 CIRCUIT DESCRIPTION 5.7 Local Microphone Input5.7 Local Microphone InputThe local microphone input is provided for use with a standard low impedance dynamicmicrophone. The microphone output is amplified by U9a before connecting to analogueswitch U10a. U10b inverts the local microphone PTT input to switch U10a ON when themicrophone PTT button is pressed. U10a is OFF at all other times.The local microphone audio has priority over the other inputs. Activation of the localmicrophone PTT input switches OFF the audio from the line or direct inputs through D16 andU10c5.8 CTCSS and Tone FilterThe CTCSS encoder module H1, under control of the main microprocessor U13, can encodeall 38 EIA tones and (on some models) additional commonly-used tones.The tone output of H1 connects to jumper JP8 which is used to select either H1 or an externaltone source. The selected source is coupled to U9c which is a balanced input unity gainamplifier. The buffered tone from U9c is fed to 300 Hz low pass filter U7c.On Rev 4 or later revisions, the low pass filter can be by passed by inserting a jumper ontoJP17.RV3, the tone deviation trimmer, is used to adjust the level of the tone from U7c before it iscombined with the voice audio signal in the summing amplifier U7a.Back to back diodes D4 and D5 limit the maximum tone signal amplitude to preventexcessive tone deviation when external tone sources are used.The subtone amplifier, filter and limiter can be bypassed on Rev 4 or later exciters byremoving the link from JP22 and moving the link in JP16 to the alternate position.5.9 Audio Signal ProcessingJumper JP4 selects either the line or direct input source. The selected source is thenconnected to JP6. JP6 can be removed to provide 20 dB attenuation when the input level isabove 10 dBm to expand the useful range of the line level trimmer RV4. The wiper of RV4 iscoupled to the input of the input amplifier U9d. U9d provides a voltage gain of ten beforeconnecting to the input of analogue switch U10c.The outputs of U10a and U10c are connected to the frequency response shaping networksC52, R133 (for 750µs pre-emphasis) and C61, R55 (for flat response). JP7 selects the pre-emphasized or flat response.The audio signal is further amplified 100 times by U7d. U7d also provides the symmetricalclipping required to limit the maximum deviation. The output level from U7d is adjusted byRV1, the deviation adjustment, before being combined with the tone audio signal in thesumming amplifier U7a.
___________________________________________________________________________RF Technology T800 Page 165.10 PTT and DC Remote Control 5 CIRCUIT DESCRIPTIONThe composite audio from U7a is fed through the 3Khz low pass filter U7b. When the linkson JP23 are in their default state, the filtered audio is coupled to the TCXO voltage tuninginput and the modulation balance trimmer RV2. RV2, R99 and R98 attenuate the modulationsignal before applying it to the VCO via varactor D3.When DMTX board option is required, Jumper JP23 allows the audio paths to be re-routed.The DMTX board provides for an external digital modulation input signal. When the twolinks on JP23 are positioned in the middle of the 6 pin header, the audio from the exciter ispassed to the DMTX board via pin 5 of JP15, where the signal is conditioned and thenreturned from the DMTX board via pin 2 of JP15, and passed to the two modulation points.RV2 adjusts level of the audio used to modulate the VCO. This primarily effects the deviationof audio frequencies above 500 Hz. RV2 is used to balance the high and low frequencydeviation to obtain a flat frequency response relative to the desired characteristic.5.10 PTT and DC Remote ControlTwo main PTT inputs are provided. The first, a direct logic level input, is connected to pin 3of the system connector. The transmitter can be keyed by applying a logic low or ground onpin 3. Pin 3 connects to the PTT logic and microprocessor through D10.DC current loop control can be used for remote PTT operation. The current loop can beconfigured by JP9, JP10 and JP11 for use with either a remote free switch or a remoteswitched source.Opto-isolator ISO1 is used to isolate the loop current signal from the transmitter PTT logic.The loop current passes through the input of ISO1 and the output of ISO1 connects to the PTTlogic.A bridge consisting of diodes D6, D8, D9 and D14 ensures correct operation regardless of thecurrent polarity. Q17 limits the current and D7 limits the voltage input of ISO1. Any lowvoltage current source capable of providing 2mA at 4V or switching circuit with less than4.8k¿ loop resistance can be used to switch the DC loop.The test PTT button on the front panel and the local microphone PTT button will also key thetransmitter. Both of these also mute the line audio input. The microphone line also enablesthat audio input.A DMTX board can also cause the exciter to key up. When TX (or TTL_TX) signal isreceived by the DMTX board, it pulls pin 6 of JP15 low, which in turn asserts thePTT_WIRE-OR signal, causing the microprocessor (U13) to key the exciter up.5.11 Microprocessor ControllerThe microprocessor controller circuit uses a single-chip eight bit processor and severalsupport chips. The processor U13 includes non-volatile EE memory for channel frequencies,tones, and other information. It also has an asynchronous serial port, a synchronous serialport and an eight bit analogue to digital converter.
___________________________________________________________________________RF Technology T800 Page 175 CIRCUIT DESCRIPTION 5.12 Voltage RegulatorThe program is stored in U5, a CMOS EPROM. U4 is an address latch for the low orderaddress bits. U2 is used to read the channel select lines onto the data bus. U11 is an addressdecoder for U5 and U2. U3 is a supervisory chip which keeps the processor reset unless the+5 Volt supply is within operating limits. U1 translates the asynchronous serial port data tostandard RS232 levels.The analogue to digital converter is used to measure the forward and reverse power, tuningvoltage and dc supply voltage.If the processor detects that the PTT_WIRE_OR signal is asserted low, it will attempts to keythe exciter up. If will first attempt to key the VCO through Q10, and if the LD pin goes high,it will switch the 9.2 Volt transmit line through Q14 and Q16. asserting Q16 has the effect ofalso asserting the yellow Tx LED (D12) on the front panel, enabling the local 25W poweramplifier, and causing the T/R Relay output to be pulled low. D24 is 30 volt zener whichprotects Q25 from both excessive voltages or reverse voltages.Should there be a problem with either the tuning volts, or the battery voltage, the VCOlocking, the forward power, or the reverse power, the microprocessor will assert the ALARMLED, through Q1. Depending on the setting of Jumper JP19, the ALARM signal can bebrought out on pin 7 of P3.5.12 Voltage RegulatorThe dc input voltage is regulated down to 9.4 Vdc by a discrete regulator circuit. The seriespass transistor Q23 is driven by error amplifiers Q8 and Q18. Q9 is used to start up theregulator and once the circuit turns on, it plays no further part in the operation.The +5 Volt supply for the logic circuits is provided by an integrated circuit regulator U14which is run from the regulated 9.4 Volt supply.Jumper JP18 is not normally fitted to the board, and is bridged with a 12mil track on thecomponent side of the board. It is provided so that the 9.4V load can be isolated from thesupply by the service department to aid in fault finding.Jumpers JP20 and JP21 are also not normally fitted on the board, and are usually bridged witha 12mil track on the component side. They allow U14 to be isolated from its input, or itsoutput or both.6Field Alignment ProcedureThe procedures given below may be used to align the transmitter in the field. Normally,alignment is only required when changing operating frequencies, or after componentreplacement.The procedures below do not constitute an exhaustive test or a complete alignment of themodule, but if successfully carried out are adequate in most circumstances.
___________________________________________________________________________RF Technology T800 Page 186.1 Standard Test Condition 6 FIELD ALIGNMENT PROCEDURETCXO calibration may be periodically required owing to normal quartz crystal aging. A driftof 1ppm/year is to be expected.Each alignment phase assumes that the preceding phase has been successfully carried out, orat least that the module is already in properly aligned state with respect to precedingconditions.6.1 Standard Test ConditionThe following equipment and conditions are assumed unless stated otherwise:•AF signal generator with 600Ω impedance, 50-3000Hz frequency range, with level set to387mV RMS.•Power supply set to 13.8Vdc, with a current capable of >5A.•RF 50Ω load, 30W rated, return loss <-20dB.•Jumpers set to factory default positions.Alignment FrequencyModel Range Align FT800A 806-830 818MHzT800B 850-870 860MHzT800C 928-942 935MHz6.2 VCO Alignment1. Select a channel at the center frequency (half way between the highest and lowestfrequencies for the model in question).2. Disconnect the Audio input (no signal input).3. Key the PTT line.4. Measure the voltage between pins 9 and 1 of the test socket (TUNE V), and adjust C99 to obtain 4.5±0.25V, while the TX LED is ON and the ALARM LED is OFF.6.3 TCXO Calibration1. Select a channel at the center frequency (half way between the highest and lowestfrequencies for the model in question).2. Disconnect the Audio input (no signal input).
___________________________________________________________________________RF Technology T800 Page 196 FIELD ALIGNMENT PROCEDURE 6.4 Modulation Balance3. Key the PTT line.4. Measure the carrier frequency at the output connector, and adjust XO1 until the correctcarrier frequency is measured, ±50Hz.6.4 Modulation Balance1.Set RV3 fully counter clockwise (CCW) (sub-tone off).2.Set RV1 fully clockwise (CW) (maximum deviation)3. Set RV2 mid-position4. Set JP7 for flat response5. Set JP4 for Hi-Z input6. Key the transmitter on7. Set the audio input to 150Hz, 0dBm.(387mV)8.Measure deviation and adjust RV4 (line Level) for a deviation of 5kHz (2.5kHz fornarrow band transmitters).9. Set the audio input to 1.5kHz, 0dBm.10. Adjust RV2 (Mod. Bal.) for a deviation of 5kHz (2.5kHz for narrow band transmitters).11. Repeat steps 6-9 until balance is achieved.12. Key the transmitter off.13. Return JP7 to its correct setting.14.Carry out the Deviation (section 6.6) and Tone Deviation (section 6.5) alignmentprocedures.6.5 Tone Deviation1. Remove the audio input.2. Key the transmitter on3. Adjust RV3 for the desired deviation in the range 0-1kHz.1 If sub-tone(CTCSS) coding is not to be used, adjust RV3 fully CCW._________________________1 The factory default is 500Hz for wide band (5kHz maximum deviation) and 250Hz for narrow band channels.
___________________________________________________________________________RF Technology T800 Page 206.6 Deviation 6 FIELD ALIGNMENT PROCEDURE6.6 Deviation1.Set RV4 (Line Level) fully clockwise (CW).2. Set the audio to 1kHz, 0dBm, on the line input.3. Key the transmitter on.4.Adjust RV1 (Set Max. Deviation) for a deviation of 5kHz (2.5kHz for narrow bandtransmitters).5. Key the transmitter off.6.Carry out the Line Input Level alignment procedure (section 6.7)6.7 Line Input Level1.Set the audio to 1kHz, 0dBm, on the line input, or use the actual signal to betransmitted.2. Key the transmitter on.3.Adjust RV4 (line level) for 60% of system deviation (3kHz or 1.5kHz for narrow bandsystems).4. If the test signal is varying, RV4 may be adjusted to produce a level of 234mV RMS or660mVp-p at the audio voltage test connector pin 6 to pin 1.5. Key the transmitter off.6.8 Output Power1. No audio input is required2. Key the transmitter on.3. Adjust RV1 on the power amplifier PCB for the desired power level at the outputconnector. 24. Key the transmitter off.____________________2 Be sure to set the power below the rated maximum for the model of transmitter. If in doubt, allow 1.5dBcable and connector losses, and assume that the maximum rated power is 15W. This means no more than 10Wat the end of a 1m length of test cable. This pessimistic procedure is safe on all models manufactured at the timeof writing.
___________________________________________________________________________RF Technology T800 Page 217SPECIFICATIONS 7.1 Overall Description7SPECIFICATIONS7.1 Overall DescriptionThe transmitter is a frequency synthesized, narrow band FM unit, normally used to drive a 50watt amplifier. It can also be used alone in lower power applications.Various models allow 2-25W of output power to be set across a number of UHF frequencybands. All necessary control and 600Ω line interface circuitry is included.7.1.1 Channel CapacityAlthough most applications are single channel, it can be programmed for up to 100 channels,numbered 0 - 99. This is to provide the capability of programming all channels into all of thetransmitters used at a given site. Where this facility is used in conjunction with channel-setting in the rack, exciter modules may be “hot-jockeyed” or used interchangeably. This canbe convenient in maintenance situations.7.1.2 CTCSSFull EIA sub-tone capability is built into the modules. The CTCSS tone can be programmedfor each channel. This means that each channel number can represent a unique RF and tonefrequency combination.7.1.3 Channel ProgrammingThe channel information is stored in non-volatile memory and can be programmed via thefront panel test connector using a PC and RF Technology software.7.1.4 Channel SelectionChannel selection is by eight channel select lines. These are available through the rear panelconnector. Internal presetting is also possible. The default (open-circuit) state is to selectchannel 00.A BCD active high code applied to the lines selects the required channel. This can besupplied by pre-wiring the rack connector so that each rack position is dedicated to a fixedchannel. Alternatively, thumb-wheel switch panels are available.7.1.5. MicroprocessorA microprocessor is used to control the synthesizer, tone squelch, PTT function and facilitatechannel frequency programming. With the standard software, RF Technology modules alsoprovide fault monitoring and reporting.
___________________________________________________________________________RF Technology T800 Page 227.2 Physical Configuration 7 SPECIFICATIONS7.2 Physical ConfigurationThe transmitter is designed to fit in a 19 inch rack mounted sub-frame. The installed height is4 RU (178 mm) and the depth is 350 mm. The transmitter is 63.5 mm or two Eclipse moduleswide.7.3 Front Panel Controls, Indicators, and Test Points7.3.1 ControlsTransmitter Key - Momentary Contact Push ButtonLine Input Level - screwdriver adjust multi-turn pot7.3.2 IndicatorsPower ON - Green LEDTx Indicator - Yellow LEDFault Indicator - Flashing Red LEDExternal ALC - Green LEDExternal Reference - Green LED7.3.3 Test PointsLine Input – Pin 6 + Ground (pin 1)Forward Power – Pin 8 + Ground (pin 1)Reverse Power – Pin 4 + Ground (pin 1)Tuning Voltage – Pin 9 + Ground (pin 1)Serial Data (RS-232) – Pins 2 / 3 + Ground (pin 1)7.4 Electrical Specifications7.4.1 Power RequirementsOperating Voltage - 10.5 to 16 Vdc with output power reduced below 12 VdcCurrent Drain - 5A Maximum, typically 0.25A StandbyPolarity - Negative Ground
___________________________________________________________________________RF Technology T800 Page 237 SPECIFICATIONS 7.4.2 Frequency Range and Channel Spacing7.4.2 Frequency Range and Channel SpacingFrequency 25 kHz 12.5 kHz806-830 MHz T800A T800AN850-870 MHz T800B T800BN928-942 MHz T800C T800CN7.4.3 Frequency Synthesizer Step SizeStep size is 10 / 12.5kHz or 5 / 6.25kHz, fixed, depending upon model7.4.4 Frequency Stability±1 ppm over 0 to +60 C, standard±1ppm over -20 to +60 C, optional7.4.5 Number of Channels100, numbered 00 - 997.4.6 Antenna Impedance50Ω7.4.7 Output powerPreset for 2-15 or 2-25W depending upon model7.4.8 Transmit Duty Cycle100% to 40C, de-rating to zero at 60C.100% to 5000ft altitude, de-rating to zero at 15,000ft.7.4.9 Spurious and HarmonicsLess than 0.25µW7.4.10 Carrier and Modulation Attack TimeLess than 20ms. Certain models have RF envelope attack and decay times controlled in therange 200µs< tr/f <2ms according to regulatory requirements.7.4.11 ModulationType - Two point direct FM with optional pre-emphasisFrequency Response - ±1 dB of the selected characteristic from 300 - 3000 Hz
___________________________________________________________________________RF Technology T800 Page 247.4.12 Distortion 7 SPECIFICATIONSMaximum Deviation - Maximum deviation preset to 2.5 or 5 kHz7.4.12 DistortionModulation distortion is less than 3% at 1 kHz and 60% of rated system deviation.7.4.13 Residual Modulation and NoiseThe residual modulation and noise in the range 300 - 3000 Hz is typically less than -50dBreferenced to rated system deviation.7.4.14 600Ω Line Input SensitivityAdjustable from -30 to +10 dBm for rated deviation7.4.15 HI-Z InputImpedance - 10KΩ Nominal, balanced inputInput Level - 25mV to 1V RMS7.4.16 Test Microphone Input200Ω dynamic, with PTT7.4.17 External Tone InputCompatible with R500 tone output7.4.18 External ALC InputOutput will be reduced 20dB by pulling the input down to below 1V. (Typically more than40dB attenuation is available.) The input impedance is ≅10kΩ, internally pulled up to rail.The external ALC input can be connected to the power control circuit in Eclipse externalpower amplifiers.7.4.19 T/R Relay DriverAn open collector transistor output is provided to operate an antenna change over relay orsolid state switch. The transistor can sink up to 250mA.7.4.20 Channel Select Input / OutputCoding - 8 lines, BCD coded 00 - 99Logic Input Levels - Low for <1.5V, High for >3.5VInternal 10K pull down resistors select channel 00 when all inputs are O/C.
___________________________________________________________________________RF Technology T800 Page 257 SPECIFICATIONS 7.4.21 DC Remote Keying7.4.21 DC Remote KeyingAn opto-coupler input is provided to enable dc loop keying over balanced lines or localconnections. The circuit can be connected to operate through the 600Ω line or through aseparate isolated pair.7.4.22 Programmable No-Tone PeriodA No-Tone period can be appended to the end of each transmission to aid in eliminatingsquelch tail noise which may be heard in mobiles with slow turn off decoders. The No-Toneperiod can be set from 0--5 seconds in 0.1 second increments. The No Tone period operatesin addition to the reverse phase burst at the end of each transmission.37.4.23 Firmware TimersThe controller firmware includes some programmable timer functions.Repeater Hang Time - A short delay or ``Hang Time'' can be programmed to be added to theend of transmissions. This is usually used in talk through repeater applications to prevent therepeater from dropping out between mobile transmissions. The Hang Time can beindividually set on each channel for 0 - 15 seconds.Time Out Timer - A time-out or transmission time limit can be programmed to automaticallyturn the transmitter off. The time limit can be set from 0-254 minutes in increments of oneminute. The timer is automatically reset when the PTT input is released.7.4.24 CTCSSCTCSS tones can be provided by an internal encoder or by an external source connected tothe external tone input. The internal CTCSS encoding is provided by a subassembly PCBmodule. This provides programmable encoding of all EIA tones.Some models encode certain extra tones.Tone frequencies are given in table 4.7.5 Connectors7.5.1 Antenna ConnectorType N Female Mounted on the module rear panel_______________________3 The reverse phase burst is usually sufficient to eliminate squelch tail noise in higher-quality mobiles
___________________________________________________________________________RF Technology T800 Page 267.4.22 Programmable No-Tone Period 7 SPECIFICATIONSFrequency EIA NumberNo Tone67.0 A169.471.9 B174.4 C177.0 A279.7 C282.5 B285.4 C388.5 A391.5 C494.8 B397.4100.0 A4103.5 B4107.2 A5110.9 B5114.8 A6118.8 B6123.0 A7127.3 B7131.8 A8136.5 B8141.3 A9146.2 B9151.4 A10156.7 B10159.8162.2 A11165.5167.9 B11171.3173.8 A12177.3179.9 B12183.5186.2 A13189.9192.8 B13196.6199.5203.5 A14206.5210.7 B14218.1 A15225.7 B15229.1233.6 A16241.8 B16250.3 A17254.1Table 4: Tone Squelch Frequencies
___________________________________________________________________________RF Technology T800 Page 277 SPECIFICATIONS 7.5.2 Power & I/O Connector7.5.2 Power & I/O Connector25-pin “D” Male Mounted on the rear panel7.5.3 Test Connector9-pin “D” Female mounted on the front panel
Eclipse Series RF Technology rfinfo@rftechnology.com.au February 2005 Revision 2 R800 Receiver Operation and Maintainance Manual This Manual is produced by RF Technology Pty Ltd 10/8 Leighton Place, Hornsby NSW 2077 Australia Copyright © 2003 RF Technology
___________________________________________________________________________ RF Technology R800 Page 2 CONTENTS CONTENTS 1 Operating Instructions 4 1.1 Front Panel Controls and Indicators 4 1.1.1 Mon Volume 4 1.1.2 Mon. Sq 4 1.1.3 N. Sq 4 1.1.4 C. Sq 5 1.1.5 Line 5 1.1.6 PWR LED 5 1.1.7 SQ LED 5 1.1.8 Alarm Led 5 2 Receiver Internal Jumper Options 6 2.1 JP1: 240Hz Notch Filter 6 2.2 JP2: Audio Response 6 2.3 JP3: Audio Filter In/Out 6 2.4 JP4: 600 Ohm Line dc Loop COS 6 2.5 JP6: COS Polarity 6 2.6 JP7, JP8, JP9 dc Loop COS Configuration (JP4 1-2) 6 2.7 JP7, JP8, JP9 Direct Output COS (JP4 2-3) 6 2.8 JP11: Eprom Type 7 3 Receiver I/O Connections 8 3.1 25 Pin Connector 8 4 Frequency Programming 8 5 Circuit Description 9 5.1 RF Section 9 5.2 IF Section 9 5.3 VCO Section 10 5.4 P.L.L. Section 10 5.5 Audio Signal Processing 10 5.6 Noise filter, Amplifier and Detector 11 5.7 Subtone Filter and CTCSS 11 5.8 External Squelch 11 5.9 Microprocessor Controller 11 5.10 Carrier Operated Switch 12 5.11 Voltage Regulator 12 5.12 Tuning Voltage Supply 12 6 Alignment Procedure 13 6.1 Standard Input Signal 13 6.2 RF Alignment 13 6.3 IF Alignment 14 6.4 Line Level Adjustment 14 6.5 Reference Oscillator Calibration 14 7 Specifications 15 7.1 General Description 15 7.1.1 Channel Capacity 15
___________________________________________________________________________ RF Technology R800 Page 3 CONTENTS CONTENTS 7.1.2 CTCSS 15 7.1.3 Channel Programming 15 7.1.4 Channel Selection 15 7.1.5 Microprocessor 15 7.2 Physical Configuration 16 7.3 Front Panel Controls, Indicators and Test Points 16 7.3.1 Controls 16 7.3.2 Indicators 16 7.3.3 Test Points 16 7.4 Electrical Specifications 16 7.4.1 Power requirements 17 7.4.2 Frequency Range and Channel Spacing 17 7.4.3 Frequency Synthesizer Step Size 17 7.4.4 Frequency Stability 17 7.4.5 Nominal Antenna Impedance 17 7.4.6 IF Frequencies 17 7.4.7 Sensitivity 17 7.4.8 Selectivity 17 7.4.9 Spurious and Image Rejection 17 7.4.10 Intermodulation 17 7.4.11 Modulation Acceptance BW 18 7.4.12 Noise Squelch 18 7.4.13 Carrier Level Squelch 18 7.4.14 Receiver Frequency Spread 18 7.4.15 Receiver Conducted Spurious Emissions 18 7.4.16 Audio Frequency Response 18 7.4.17 Audio Output Level 18 7.4.18 Audio Distortion 19 7.4.19 Channel Select Input/Output 19 7.4.20 Carrier Operated Switch Output 19 7.4.21 CTCSS 20 7.4.22 External Squelch Input 20 7.5 Connectors 20 7.5.1 Antenna Connector 20 7.5.2 Power & I/O Connector 20 7.5.3 Test Connector 20 B Parts List
___________________________________________________________________________ RF Technology R800 Page 4 1 OPERATING INSTRUCTIONS WARNING Changes or modifications not expressly approved by RF Technology could void your authority to operate this equipment. Specifications may vary from those given in this document in accordance with requirements of local authorities. RF Technology equipment is subject to continual improvement and RF Technology reserves the right to change performance and specification without further notice. 1 Operating Instructions 1.1 Front Panel Controls and Indicators 1.1.1 Mon Volume The Mon. Volume control is used to adjust the volume of the internal loudspeaker and any external speaker connected to the test socket. It does not effect the level of the 600 Ohm line or direct audio output. 1.1.2 Mon. SQ. The Mon. SQ. switch allows the normal squelch functions controlling the monitor output to be disabled. When the switch is in the Mon. SQ. position the audio at the monitor speaker is controlled by the noise detector. The CTCSS, carrier and external squelch functions are disabled. This can be useful when you are trying to trace the source of on-channel interference or when setting the noise squelch threshold. the audio from the 600Ω line and direct outputs is not effected by the switch position. 1.1.3 N.SQ The N.SQ trimpot is used to set the noise squelch sensitivity. Use the following procedure to set the noise squelch to maximum sensitivity. 1. Set the toggle switch to the Mon. Sq. position and set the Mon. Volume control to 9 o’clock. 2. Turn the N.SQ adjustment counter clockwise until the squelch opens and noise is heard from the speaker. Adjust the volume to a comfortable listening level. 3. In the absence of any on channel signal, turn the NSQ screw clockwise until the noise in the speaker is muted. Then turn the screw one additional turn in the clockwise direction.
___________________________________________________________________________ RF Technology R800 Page 5 1.1.4 C.SQ 1 OPERATING INSTRUCTIONS 1.1.4 C.SQ The C.SQ trimpot is used to set the carrier squelch sensitivity. Carrier squelch is useful at higher signal levels than noise squelch and can be used from 1-200µV input It is provided mainly for use in fixed link applications where a high minimum signal to noise ratio is required or where very fast squelch operation is required for data transmission. The carrier squelch will open and close in less than 2 mSec. In most base station applications the carrier squelch is disabled by turning the adjustment counter clockwise until the screw clicks. The carrier squelch may be set to a predetermined level with the Techelp/ Service Monitor 2000 Software or by using the following procedure. 1. First turn the adjustment fully counter-clockwise. Then set the noise squelch as above. 2. Connect a source of an on channel signal with the desired threshold level to the receiver’s RF input. 3. Turn the screw clockwise until the SQ LED goes OFF. Then turn the screw back until the LED just comes ON. 1.1.5 LINE The LINE trimpot is used to set the line and direct audio output level. It is normally set to give 0dBm (775mV) to line with a standard input signal equal to 60% of maximum deviation at 1 KHz. The level can be measured between test socket pins 6 and 1 and set as desired. 1.1.6 PWR LED The PWR LED shows that the dc supply is connected to the receiver. 1.1.7 SQ LED The SQ LED comes on when the audio to the line and direct outputs is un-squelched. The LED and squelch function are controlled by noise, carrier and tone squelch circuits. 1.1.8 ALARM LED The ALARM LED can indicate the detection of several different fault conditions by the self-test circuits. The alarm indicator shows the highest priority fault present. In order of priority the alarms are. Indication Cadence Fault Condition Flashing 5 times, pause Synthesizer unlocked Flashing 4 times, pause Tuning voltage outside limits Flashing 3 times, pause Signal level below preset threshold (for fixed links)
___________________________________________________________________________ RF Technology R800 Page 6 2 RECEIVER JUMPER OPTIONS 2.1 JP1 -240Hz Notch Filter Flashing 1 time, pause dc supply voltage low or high LED ON continuously External squelch is active 2 Receiver Internal Jumper Options In the following subsections an asterisk (*) signifies the standard (Ex Factory) configuration of a jumper. 2.1 JP1 - 240 Hz Notch Filter Condition Position Notch filter In 1-2* Notch Filter Out 2-3 2.2 JP2 Audio Response Condition Position 750µSec de-emphasis 1-2* Flat response 2-3 2.3 JP3 Audio Filter In/Out Condition Position Hi-pass & Notch In 2-3* Flat response to 3 KHz 1-2 2.4 JP4 600 Ohm Line dc Loop COS Condition Position dc Loop Configured by JP7, JP8, JP9 1-2* dc Loop Not connected 2-3 2.5 JP6 COS Polarity Condition Position Active on Signal 1-2* Active on No Signal 2-3 2.6 JP7, JP8, JP9 - dc Loop COS Configuration (JP4 1-2) Condition JP7 JP8 JP9 Source +12 Vdc Loop 2-3 ON 2-3* Free Switch Output 1-2 ON 1-2
___________________________________________________________________________ RF Technology R800 Page 7 2.7 Direct Output COS 2 RECEIVER INTERNAL JUMPER OPTIONS 2.7 JP7, JP8, JP9 Direct Output COS (JP4 2-3) Condition JP7 JP8 JP9 +12 Vdc Direct Output 2-3 OFF OFF Free Switch Output 1-2 OFF OFF 2.8 JP11 EPROM Type Condition Position 27C256 2-3* 27C64 1-2 *= Standard Ex-Factory Configuration
___________________________________________________________________________ RF Technology R800 Page 8 3 RECEIVER CONNECTIONS 3.1.25 Pin Connector 3 Receiver I/O Connections 3.1 25 Pin Connector The D-shell 25 pin connector is the main interface to the receiver. The pin connections are described in table 3. Function Signal Pins Specification DC Power +12Vdc 0 Vdc 1,14 13,25 +11.4 to 16Vdc Channel select 1 2 4 8 10 20 40 80 21 9 22 10 23 11 24 12 BCD Coded 0 = Open Circuit or 0 Vdc 1 = +5 to +16Vdc RS232 Data In Out 15 2 Test and Programming use 9600, 8 data 2 stop 600 Ohm Line High Low 20 6 Transformer Isolated Balanced 0 dBm Output 150 Ohm/Hybrid Access 7 19 Discriminator Audio Disc 18 AC coupled, unsquelched Direct Audio Output Audio 17 Direct AC Coupled Audio Audio Ground Agnd 5 Direct Audio Ground Sub-Audible Audio Output Tone 4 Unsquelched, 1-250 Hz Carrier Operated Switch COS+ COS- 3 16 Opto-coupled Transistor Switch (10mA) External Squelch Ext Sq 8 <1 Vdc to Squelch >2 Vdc or open ckt to unsquelch Table 3: Pin connections and explanations for the main, 25-pin D-shell Connector 4 Frequency Programming Channel and tone frequency programming is most easily accomplished with RF Technology TecHelp/ Service Monitor 2000 Software. This software can be run on any IBM compatible PC and provides a number of additional useful facilities. TecHelp/ Service Monitor 2000 allows setting of the adaptive noise squelch threshold, provides a simple means of calibrating the signal strength output and minimum signal alarm
___________________________________________________________________________ RF Technology R800 Page 9 5.1 RF Section 5 CIRCUIT DESCRIPTION . TecHelp/ Service Monitor 2000 can be supplied by your dealer, distributor or by contacting RF Technology direct. 5 Circuit Description The following description should be read as an aid to understanding the block and schematic diagrams at the rear of this manual. 5.1 RF Section A two section helical filter FL1 is used to limit the R.F. bandwidth prior to the R.F. amplifier transistor Q1. The output impedance of FL1 is matched to the input of Q1 by C177, C178 and a microstrip line on the printed circuit board. Q1 is a very low noise device with good intermodulation performance. A four section filter consisting of FL2 and FL3 is used between Q1 and the mixer MX1. This filter provides additional image and spurious frequency rejection. MX1 is a high level double balanced diode ring mixer with excellent intermodulation performance. It has a conversion loss of approximately 7dB. The gain between the receiver input and the mixer input is approximately 10dB so that the total gain between the antenna input and the I.F. input is 3-4dB. Monolithic amplifiers MA1, MA2 and transistor Q5 amplify the VCO output to the necessary L.O. level for MX1 approximately +13dBm. The network C8, C9, L1-3 and R6 passes the 45MHz I.F. frequency to the I.F. amplifier and terminates the R.F. and L.O. frequency components. 5.2 I.F. Section The first I.F. amplifier uses two parallel connected JFET transistors Q2 and Q3 to obtain 8-10dB gain. The two transistors provide improved dynamic range and input matching over a single transistor. A two pole 45MHz crystal filter XF1 is used between the first and second I.F. amplifiers. The second I.F. amplifier Q4 provides additional gain of 6-10dB. A two pole crystal filter is used between Q4 and the 2nd oscillator mixer. These two crystal filters provide some adjacent channel rejection and all of the second I.F. image frequency rejection. U1 is a monolithic oscillator and mixer I.C. It converts the 45MHz I.F. signal down to 455KHz. The second oscillator frequency or 45.455MHz is controlled by crystal Y1. The 455KHz output of the second mixer is fed through the ceramic filter CF1 to the 2nd I.F. amplifier transistor Q27. Q27 provides an additional 15dB gain ahead of the limiter and discriminator I.C. U3. CF1 provides additional adjacent channel selectivity for 25KHz versions and all of the adjacent channel selectivity for 12.5KHz versions. CF1 and termination resistors R15 and R24 are the only component differences between the 12.5 and 25KHz versions.
___________________________________________________________________________ RF Technology R800 Page 10 5 CIRUCIT DESCRIPTION 5.3.0 VCO Section The limiter/discriminator I.C. U3 further amplifies the signal and passes it through CF2. CF2 does not contribute to the adjacent channel rejection but is used to reduce the wide band noise input to the limiter section U3. The limiter section of U3 drives the quadrature detector discriminator. C31 and I.F. tuned circuit L10 comprise the discriminator phase shift network. U3 also has a received signal strength indicator output (RSSI). The RSSI voltage connects to the test socket for alignment use. The RSSI voltage is also used by the microprocessor for the adaptive noise squelch, carrier squelch and low signal alarm functions. Dual op-amp U2 is used to amplify and buffer the discriminator audio and RSSI outputs. 5.3 V.C.O Section The Voltage controlled Oscillator uses a bipolar junction transistor Q6 which oscillates at the required mixer injection frequency. A fixed tuned ceramic coaxial resonator CR1 is used to set the tuning range. Varactor diode D18 is used by the P.L.L. circuit to keep the oscillator locked on the desired frequency. Transistor Q7 is used as a filter to reduce the noise on the oscillator supply voltage. 5.4 P.L.L. Section The synthesizer frequency reference is supplied by a temperature compensated crystal oscillator (XO1). the frequency stability of the TCXO is better than 1ppm over the operating temperature range. The 12.8MHz output of XO1 is amplified by Q8 to drive the reference input of the P.L.L. synthesizer I.C. U4. This I.C. is a single chip synthesizer which includes a 1.1GHz pre-scaler, programmable divider, reference divider and phase/frequency detector. The frequency data is entered by a serial data link from the microprocessor. The phase detector output signals from U4 are used to control two switched current sources. The output of the positive and negative sources Q10 and Q15, produce the tuning voltage which is smoothed by the loop filter components to bias the V.C.O. varactor diode D18. 5.5 Audio Signal Processing A 4KHz low pass filter (U27b) is used to remove high frequency noise from the signal. A 300Hz high pass filter (Y26a,b) then removes the sub-audible tones. A 240Hz notch filter (U26c,d) is used to improve the rejection of tones above 200Hz. The high pass and notch filters can be bypassed by internal jumpers JP1 and JP3. The audio frequency response can be set for either a 750uS de-emphasis or flat characteristic by JP2. JP2 switches the feedback networks of amplifier U27c to achieve the desired response. After de-emphasis and filtering, the audio signal is applied to the inputs of two analog switches (U17a,b). These switches are controlled by the microcontroller and squelch or mute
___________________________________________________________________________ RF Technology R800 Page 11 5.6 Noise Filter, Amplifier and Detector 5 CIRCUIT DESCRIPTION the audio to the line and monitor output circuits. The monitor output can be set for noise squelch only operation by S1. The audio from U17a is adjusted by the volume control before connecting to the monitor output amplifier U5. U5 drives the internal speaker and can also supply 3-5 watts to an external loudspeaker. The audio from U17b is adjusted by RV3 before connecting to the line output I.C. (U22a,b). U22 is a dual amplifier connected in a bridge configuration to drive the 600 Ohm line output transformer T1. 5.6 Noise Filter, Amplifier and Detector The unfiltered audio from the discriminator is fed to trimpot RV4 which is used to set the noise squelch threshold. From RV4 the audio goes to the noise filter (U27a). This is a 10KHz high pass filter and is used to eliminate voice frequency components. The noise signal is then amplified by U27d and fed to the noise detector. The noise detector consists of D6, Q17 and U26c. D6 and Q17 are a charge pump detector and pull the input to U26c low as the noise increases. U26c has positive feedback and acts like a schmidt trigger. The output of U26c goes high when noise is detected. It connects to the microcontroller and to analog switch U17d. U17d varies the gain of the noise amplifier to provide approximately 2dB hysteressis. 5.7 Subtone Filter and C.T.C.S.S. The discriminator audio is fed through cascaded low pass filters U28a and U28b to filter out the voice frequency components. The filtered sub-tone audio is supplied to the C.T.C.S.S. hybrid and the rear panel system connector. The filtered output can be used for re-transmission of C.T.C.S.S. or D.C.S. The C.T.C.S.S. decoder module is a microcontroller base hybrid module. Under control of the main microprocessor U15 it can decode all 38 E.I.A. tones and 12 additional commonly used tones. The decode bandwidth is set to 1% but may be changed to 2% by a jumper on the printed circuit board. 5.8 External Squelch The audio output can be muted through pin 8 of the receiver system connector P1. When pin 8 is pulled to less than 1 Volt above ground, the microcontroller U15 will mute the audio output. This facility can be used to mute the audio during transmission, as is required in single frequency systems, by simply connecting pin 8 of the receiver to the transmitter T/R relay driver output (pin 16 on Eclipse transmitters).
___________________________________________________________________________ RF Technology R800 Page 12 5 CIRCUIT DESCRIPTION 5.10 Carrier Operated Switch 5.9 Microprocessor Controller The microprocessor controller circuit uses an advanced eight bit processor and several support chips. The processor U15 includes EE memory for channel frequencies, tones and other information. It also has an asynchronous serial port, a synchronous serial port and an analog to digital convertor. The program is stored in U12, a CMOS EPROM. U13 is an address latch for the low order address bits. U11 is used to read the channel select lines onto the data bus. U7 is an address decoder for U11 and U12. U14 is a supervisory chip which keeps the processor reset unless the +5 Volt supply is within operating limits. U16 translates the asynchronous serial port data to standard RS232 levels. The analog to digital converter is used to measure the received signal strength, tuning voltage, dc supply voltage and the carrier squelch setting. 5.10 Carrier Operated Switch The carrier operated switch is an opto-coupled (IS01) output. Internal jumpers (JP4,7,8,9) can be connected to provide loop source, loop switch, free switch and various other configurations. The C.O.S. can be set to active (switch closed) on carrier or active in the absence of carrier. The generic term “Carrier Operated Switch” may be misleading in this case. If a sub-audible tone has been programmed for the channel current channel, the C.O.S. will be controlled by carrier and tone detection. 5.11 Voltage Regulator The dc input voltage is regulated down to 9.4Vdc by a discrete regulator circuit. The series pass transistor Q20 is driven by error amplifiers Q21 and Q22. Q23 is used to start up the regulator and once the circuit turns on it plays no further part in the operation. This circuit is short circuit and overload protected. It provides much better line isolation and lower dropout voltage than can be obtained with current integrated circuit regulators. 5.12 Tuning Voltage Supply U18 is an astable multivibrator. The output from pin 3 of U18 is a rectangular 8 volt waveform with a frequency of approximately 200KHz. This output is connected to a voltage tripler circuit consisting of C170-C173, D13 and D14 to produce +20Vdc. This is used by the frequency synthesizer to provide tuning voltages up to +18Vdc. 6 Alignment Procedure The following procedures may be used to align the receiver for optimum performance. Normally alignment should only be necessary after repairs on that part of the circuit.
___________________________________________________________________________ RF Technology R800 Page 13 6.1 Standard Input Signal 6 ALIGNMENT PROCEDURE TCXO calibration may be required periodically due to crystal aging. The aging should be less than 1ppm/year. 6.1 Standard Input Signal RF Signal Generator 50? output impedence Frequency range 806-950MHz FM modulation at 1KHz 1.5KHz peak for 12.5KHz channel spacing 3.0KHz peak for 25KHz channel spacing 6.2 RF Alignment Step Input Measure Adjust 1 Select alignment frequency channel dc Volts on TP3 (next to FL4) FL4 for maximum dc volts 2 Signal generator on centre frequency channel to J1. Modulation off. dc Volts on test socket pin 7 to pin 1 Generator level to read 2-3Vdc 3 As above As above FL1,FL2,FL3 for maximum reading. Reduce generator output to keep below 3Vdc.
___________________________________________________________________________ RF Technology R800 Page 14 6.3 IF Alignment 6 ALIGNMENT PROCEDURE 6.3 IF Alignment Step Input Measure Adjust 1 Signal generator on centre frequency channel to J1. Modulation OFF. dc Volts on test socket pin 7 to pin 1 Generator level to read 2-3Vdc. 2 As above As above L5,L6,L7,L8 For max. Reduce generator output to keep below 3Vdc 3 Set generator level to 10uV Frequency U3 pin 9 L9 to read 455KHz +/- 10Hz 4 Set generator level to 1 millivolt. Modulation ON Audio level test socket pin 6 to pin 1 Line level (RV3) to obtain approx. 1Vrms 5 As Above As Above L10 for maximum 6 As above Audio level P1 pin 18 to pin 5 RV1 for .5Vrms 7 Set generator level to approx 0.25uV SINAD on test socket pin 6 to pin 1 Reduce generator level to obtain 12dB SINAD. Carefully adjust L5,L6,L7,L8 to obtain the best SINAD. Reduce the generator output to maintain 12dB SINAD. 6.4 Line Level Adjustment Step Input Measure Adjust 1 Signal generator on centre frequency channel to J1. Modulation ON. Level 1 millivolt Audio level test socket pin 6 to pin 1 RV3 for 775mV rms 6.5 Reference Oscillator Calibration Step Input Measure Calibration 1 None required Frequency Junction of R69 and R26 on the top of the PCB. (L.O. input to the mixer) X01 for L.O. +/- 100Hz L.O. =Fc+45MHz
___________________________________________________________________________ RF Technology R800 Page 15 7 SPECIFICATIONS 7 Specifications 7.1 General Description The receiver is a high performance, frequency synthesized, narrow band FM unit which can be used in conjunction with transmitter and power supply modules as a base station or as a stand alone receiver. All necessary control and 600 Ohm line interface circuitry is included. 7.1.1 Channel Capacity Although most applications are single channel, it can be programmed for up to 100 channels numbered 0-99. This is to provide the capability of programming all channels into all of the receivers used at a given site. 7.1.2 CTCSS The CTCSS tone or no tone can also be programmed for each channel. Each channel number can represent a unique RF and tone frequency combination. 7.1.3 Channel Programming The channelling information is stored in a non-volatile memory chip and can be programmed via the front panel test connector using a PC and RF Technology supplied TecHelp/ Service Monitor 2000 software. 7.1.4 Channel Selection Channel selection is by eight channel select lines. These are available through the rear panel connector. A BCD active high code applied to the lines selects the required channel. This can be supplied by pre-wiring the rack connector so that each rack position is dedicated to a fixed channel. BCD switches inside the receiver can be used to pre-set any desired channel. These eliminate the need to externally select the channel. 7.1.5 Microprocessor A microporcessor is used to control the synthesizer and squelch functions and facilitate the channel frequency programming. With the standard software it also can provide some rudimentary fault monitoring and reporting.
___________________________________________________________________________ RF Technology R800 Page 16 7.2 Physical Configuration 7 SPECIFICATIONS 7.2 Physical Configuration The receiver is designed to fit in a 19 inch rack mounted frame. The installed height is 4RU (178mm) and the depth 350mm. The receiver is 63.5mm or two eclipse modules wide. 7.3 Front Panel Controls, Indicators and Test Points 7.3.1 Controls Mute Defeat Switch - toggle (Overrides CTCSS and carrier squelch at the monitor output). Monitor Speaker Volume - Knob Line Output Level - Screwdriver adjust multiturn pot Noise Sq. Setting - Screwdriver adjust multiturn pot Carrier Sq. Setting - Screwdriver adjust multiturn pot 7.3.2 Indicators Power On - Green LED Squelch Open - Yellow LED Fault Indicator - Flashing Red LED 7.3.3 Test Points Line Output Level - 6 + Gnd (pin 1) Receive Signal Strength - 7 + Gnd (pin 1) Tuning Voltage - 9 + Gnd (pin 1) Serial data (RS232) - 2/3 + Gnd (pin 1) 7.4 Electrical Specifications 7.4.1 Power Requirements Operating Voltage - 10.5 to 16Vdc Current Drain - 500mA Max Polarity - Negative Ground
___________________________________________________________________________ RF Technology R800 Page 17 7 SPECIFICATIONS 7.4.2 Frequency Range and Channel Spacing 7.4.2 Frequency Range and Channel Spacing Model No. Frequency 25KHz 12.5KHz 800-830MHz R800A R800AN 850-870MHz R800B R800BN 896-930MHz R800C R800CN 7.4.3 Frequency Synthesizer Step Size -10.0 or 12.5KHz 7.4.4 Frequency Stability +/- 1ppm, 0 to +60C, Standard 7.4.5 Nominal Antenna Impedance 50 Ohms 7.4.6 IF Frequencies 1st IF Frequency 45MHz 2nd IF Frequency 455KHz 7.4.7 Sensitivity 0.25uV (-119dBm) for 12dB SINAD 0.35uV (-116dBm) for 20dB Quieting 7.4.8 Selectivity 25KHz spacing - 80dB per EIA-603 12.5KHz spacing - 70dB per EIA-603 7.4.9 Spurious and Image Rejection 90dB 7.4.10 Intermodulation 80dB per RS204C
___________________________________________________________________________ RF Technology R800 Page 18 7.4.11 Modulation Acceptance BW 7 SPECIFICATIONS 7.4.11 Modulation Acceptance BW 25KHz spacing - 7.5KHz per EIA-603 12.5KHz spacing - 3.75KHz per EIA-603 7.4.12 Noise Squelch Adjustment Range 6-26dB SINAD, 25KHz Versions 6-18dB SINAD, 12.5KHz Versions Attack Time 20mSec. above 20dB Quieting Release Time 150mSec. at 20dB quieting decreasing to 20mSec. above 2uV present threshold Hysteresis Hysteresis is equal to approximately 2dB change in noise quieting. 7.4.13 Carrier Level Squelch Carrier level squelch can be used when it is necessary to set the opening point above 26dB SINAD as may be required in link applications. The minimum adjustment range is 1 to 200uV. 7.4.14 Receiver Frequency Spread Less than 1dB change in sensitivity over 10MHz 7.4.15 Receiver Conducted Spurious Emissions Less than -57dBm from 1 to 2900MHz 7.4.15.1 Audio Frequency Response 600 Ohm Line and Direct Output: +1/-3dB 300-3000Hz relative to either a flat response or 750uSec. de-emphasis with the high pass and notch filters bypassed. Sub Audio Output: +1/-3dB 67-250Hz 7.4.15.2 Audio Output Level 600 Ohm Line: Adjustable -10 to +10dBm Monitor Loudspeaker: 5watts with external speaker. 0.3watt with internal speaker.
___________________________________________________________________________ RF Technology R800 Page 19 7 SPECIFICATIONS 7.4.18 Audio Distortion Discriminator and Sub-Audio Level: Nominally equal to 1 volt peak at rated system deviation. 7.4.16 Audio Distortion With 750uSec. De-Emphasis: Less than 3% at 1KHz and 60% of rated system deviation. With Flat Response: Less than 5% at 1KHz and 60% of rated system deviation. 7.4.17 Channel Select Input/Output Coding: 8 Lines BCD coded 00-99 Logic Input Levels: 0=<0.4Volts 1=>3.5Volts Internal 10K pull down resistors selects Ch.00 when all inputs are O/C. 7.4.20 Carrier Operated Switch Output Floating Opto-Coupler Output: The carrier operated switch output is via an opto-coupler. Collector and emitter connections are available to allow connection for source or sink. The opto-coupler can be linked inside the receiver to be on when a carrier is detected or to be on in the absence of carrier. Connection to Remote Switch via 600? Line: Internal connections are provided so that the opto-coupler can be connected to the 600? line for use over a single pair. Current Source/Sink, Collector Voltage: Ic = 10mA Maximum Vc = 30Volts Maximum.
___________________________________________________________________________ RF Technology R800 Page 20 7.4.21 CTCSS 7 SPECIFICATIONS 7.4.21 CTCSS The CTCSS decoding is provided by a hybrid module. This provides programmable decoding of all 38 EIA and 12 other common tones. TONE SQUELCH FREQUENCIES Tone Freq. EIA# Tone Freq. EIA# Tone Freq. EIA# No Tone 114.8 A6 179.9 B12 67.0 A1 118.8 B6 183.5 69.4 123.0 A7 186.2 A13 71.9 B1 127.3 B7 189.9 74.4 C1 131.8 A8 192.8 B13 77.0 A2 136.5 B8 196.6 79.7 C2 141.3 A9 199.5 82.5 B2 146.2 B9 203.5 A14 85.4 C3 151.4 A10 206.5 88.5 A3 156.7 B10 210.7 B14 91.5 C4 159.8 218.1 A15 94.8 B3 162.2 A11 225.7 B15 97.4 165.5 229.1 100.0 A4 167.9 B11 233.6 A16 103.5 B4 171.3 241.8 B16 107.2 A5 173.8 A12 250.3 A17 110.9 B5 177.3 254.1 7.4.22 External Squelch Input An external input is provided to squelch or mute the receiver audio output. This may be used in conjunction with an external decoder or to mute the receiver during transmissions. The External Squelch Input can be connected to the T/R Relay pin on Eclispe transmitters to mute the receiver during transmission. 7.5 Connectors 7.5.1 Antenna Connector Type N Female Mounted on the module rear panel 7.5.2 Power & I/O Connector 25 pin “D” Male Mounted on the rear panel 7.5.3 Test Connector 9 pin “D” Female mounted on the front panel.

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