HARRIS TR-391-A2 Mobile Radio User Manual

HARRIS CORPORATION Mobile Radio KME Instruction

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Users Manual

KME 900 Instruction Draft1, Receiver CircuitThe FM dual-conversion super heterodyne receiver is designed for operation in the 935-941MHz frequencyrange.The Receiver has intermediate frequencies (IF) of 82.2MHz and 455KHz.Adjacent channel selectivity is obtained by using two band pass filters, a 82.2MHz crystal filter and a 455KHzceramic filter.The FM-detector is Quadrature discriminator.1-1 Receiver Front-endA RF signal from antenna is coupled though the low pass filters, antenna switch and band pass filter to theinput of low noise amplifier TR201. The output of TR201 is coupled through band pass filter to input of 1’stMixer TR203.Front End selectivity is provided by these band pass filter.1-2 1’st MixerThe 1’st Mixer is a Transistor-Mixer (TR203), that converts a RF signal the 935-941MHz range to 82.2MHz1’st IF frequency.In the mixer stage, A RF signal from the Front-end RF filter is applied to the input of the Transistor-Mixer.1-3 1’st IFThe 82.2MHz 1’st IF output signal is coupled from the output of T201 through IF amplifier TR204 and Crystalfilter FL201 to IF-amplifier TR205.The highly-selective crystal filters FL201-1 and FL 201-2 provide the first portion of the receiver IFselectivity. The out put of the filters is coupled through the impedance-matching net work T204, C246 andR224 to 1’st IF amplifier TR205.1-4 2’nd Mixer, 2’nd IF filter,2’nd IF amplifier and FM detectorIC201 is an one-chip IC for FM communication system. It includes 2’nd Mixer, 2’nd IF amplifier and FMdetector.The 2’nd Mixer is a Balanced Mixer, that converts a 1’st IF signal 82.2MHz range to 455KHz 2’nd IFfrequency. The 2’nd IF signal is applied to Ceramic Filter FL203, which provides the 455KHz selectivity. The output of the 2’nd IF filter is applied to 2’nd IF amplifier in IC201.The 2’nd IF signal is then amplified, filtered and limited. Discriminator (DSC201) shifts the 2’nd IF signal by90deg and applies it to the internal FM detector.The FM detector compares the shifted IF signal to the internal IF signal to recover the audio modulation. Theaudio output of IC201 is applied to audio amplifier buffer IC205-2.The audio output of IC205-2 is then applied to the SYSTEM CONTROL UNIT.2, Transmitter CircuitThe Transmitter Circuit consists of one Class-A Amplifier TR101, Pre-Driver IC101, PA Module IC102, RFAmplifier TR102, Automatic Power Control Circuit (TR105- TR107), Antenna Switch (CD103, CD105-CD107 and CD109), Low Pass Filter (Micro Strip Line and C146-C153, C181 and C183).2-1 Class-A AmplifierThe 896-902MHz and 935-941MHz RF input from Synthesizer output of TR316 is applied to the band passfilter FL301 through an attenuator pad R301-R303. RF input level is about +3dBm, that is amplified to+10dBm by TR101. This is controlled by TXENB+.
2-2 Pre-DriverThe output of TR101 is applied to the Pre-Driver IC101 through an attenuator pad R106-R108. The output ofR107 is also amplified to about 600mW by IC101. This is controlled by TXENB+. The Pre-Driver consists ofthree stages RF amplifier. The first and second stages in IC101 are operated in Class-B. The third stage inIC101 is operated in Class-C.2-3 PA ModuleThe output of IC101 is applied to the PA Module IC102 through an attenuator pad R110-R112. The output ofR110 is amplified to about 13W. The PA Module consists of three stages RF amplifier. The first stage powersupply voltage is controlled by power control circuit. The second and third stage power supply voltages aresupplied by B_A+ via TR108. The first and second RF amplifiers are operated in Class-B. The third RFamplifier is operated in Class-C.2-4 RF AmplifierThe input (about 13W) of the RF Amplifier is amplified to 25W.Power Supply voltage for the RF Amplifier is connected with POWER SUPPLY BOARD through C1.2-4 Automatic Power ControlThe Automatic Power Control circuit samples the output power to the antenna to maintain a constant powerlevel across the band. Also, a thermistor circuit (TR104 and RT101) senses the PA Module temperature toreduce the power level when the temperature is above +110°C. The Automatic Power Control circuit controlsthe supply voltage to the first stage in PA Module IC102. Directional coupler provides a sample of transmitpower for diode CD102. Diode CD102 produce a positive DC voltage proportional to the transmit circuitoutput power level. When above VSWR 3, reflect coupler provides a sample of reflection power for diodeCD101. Diode CD101 and CD102 produce voltages are summed, then that is compared to APCREF (D/AVoltage) from SYSTEM CONTROL UNIT by the amplifier TR105. The collector of TR105 is applied to DCamplifier TR106 and TR107, then the output voltage of TR107 controls to the first stage of PA Module.2-5 Antenna Switch and Low Pass FilterThe Antenna Switch consists of CD103, CD105-CD107, CD109 and the Low Pass Filter consists of microstrip line and C146-C153,C181 and C183.During transmit, TXENB+ line from SYSTEM CONTROL UNIT is high level. Transistor TR109 turns onsupply +9VT to the Class-A Amplifier and Pre-Driver, Automatic Power Control circuit and PIN diodeAntenna Switch CD103, CD105-CD107 and CD109. When transmitting, the Antenna Switch diode is lowimpedance.3, Frequency Synthesizer CircuitThe Frequency Synthesizer circuit receives PLL data, and control information from the microcomputer andfrom this generates the Tx / Rx RF frequencies.It also provides frequency lock status to SYSTEM CONTROL UNIT. It consist of the Reference Oscillator,PLL Frequency Synthesizer chip IC305, Loop filter, Rx VCO TR307, Tx VCO TR304, Feedback BufferAmplifier, and Dual-Modulus Prescaler IC306. Rx VCO and Tx VCO are locked to the Reference Oscillatorby a single direct-divide synthesis loop consisting of the Feedback Buffer, Prescaler, and PLL FrequencySynthesizer chip.The Tx VCO operates over a frequency range of 448-451MHz and 467.5-470.5MHz.The Rx VCO operates over a frequency range of 426.4-429.4MHz.
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Document ID43135
Application IDfCwjLZ1O1tClae0t54D9ew==
Document DescriptionUsers Manual
Short Term ConfidentialNo
Permanent ConfidentialNo
SupercedeNo
Document TypeUser Manual
Display FormatAdobe Acrobat PDF - pdf
Filesize1.47kB (18375 bits)
Date Submitted1999-06-18 00:00:00
Date Available1999-09-22 00:00:00
Creation Date1999-06-10 11:17:02
Producing SoftwareAcrobat Distiller 3.01 for Windows
Document Lastmod0000-00-00 00:00:00
Document TitleMicrosoft Word - KME Instruction.doc
Document CreatorWindows NT 4.0
FCC ID Filing: AXATR-391-A2

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