IP Mobilenet ECSDT450TX User Manual 40674

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Document ID	40674
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Document Type	User Manual
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Date Submitted	1999-06-07 00:00:00
Date Available	1999-03-24 00:00:00
Creation Date	2001-06-21 08:28:48
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Document Lastmod	2001-06-21 08:28:50
Document Title	40674.pdf
Document Author:	jsoscia

fl“ Instrument Specialties Company, Inc. — World Compliance Center
“9
EXHIBIT B:
DT450 Product Support Manual
DT450 Product Support Manual
ECS 516-82025 Revision X1
1.1 1
1.2 1
1.3 2
1.4 General Product Dmcription ................................ 2
1.5 Functional Block Diagram .................................. 4
INTERFACE DESCRIPTION .................................... 6
2.1 External 6
2.1.1 6
2.1.2 6
2.1.3 7
2.1.4 8
SPECIFICATIONS ............................................ 9
3.1 D'I‘450 General Specifications ............................... 9
3.2 Transmitter Specifications ................................. 10
3.3 Receiver Specifications ................................... 11
3.4 Mechanical Specifications ................................. 12
3.5 Environmental Specifications ............................... 12
36 Regulatory Agency Specifications ............................ 13
3.6.1 FCC ........................................... 13
3.7 Reliability ............................................ 13
OPERATION AND MAINTENANCE 14
4.1 Modes of Operation 14
4.2 Prognmming ........ 14
....................... 15
4 3 Maintenance ........................................... 15
THEORY OF OPERATION .................................... 16
5.1 Microcontroller Section ................................... 18
5.2 4—Ievel FSK Modem Section ............................... 20
5.3 Injection Synthesizer ..................................... 21
5.4 Transmit Baseband Processing .............................. 23
5.5 UHF Receiver .......................................... 24
5.5.1 UHF Front-End Section 24
5.5.2 45 MHz Receiver Section 26
5.6 Diversity Reception Controller 27
5.6.1 RSSI Input Section . . 28
5.6.2 RSSI Level Shifter 28
5.6.3 Receiver Selector .................................. 29
5.6.4 Recovered Modulation Input .......................... 29
5.6.5 Recovered Modulation Switch ......................... 30
5.6.6 Carrier Detector ................................... 30
5.7 Receive Baseband Processing .............................. 31
5.9 TIR (Transmit/Receive) Switch ............................ 32
RECOMMENDED TOOLS AND TEST FQUIPME'NT ............... 33
6.1 Recommended Tools ................................ 33
6.2 Recommended Test Equipment ............................. 33
INSTALLATION 34
7.1 Unpacking and Inspection ................................. 34
7.2 Installation Instructions ................................... 35
7.2.1 Equipment Requirements ............................ 35
7.2.2 Installation Procedures .............................. 36
7.3 Amenm Considerations ................................... 39
7.3.1 Antenna Radiation Pattern ........................... 39
7.3.2 Antenna Neaerield Exclusion Zone .................... 39
7.3.3 Antenna Correlation Coefficient ....................... 40
8,2
10
7.3.4 Microstrip Patch Antennas ........................... 40
MAINTENANCE AND ALIGNMENT PROCEDURES ............... 41
8.1.1 Test Equipment Setup ............................... 41
..................................................... 41
RECOMMENDED TOOLS AND TEST EQUIPMENT ............... 42
8.2.1 Recommended Tools ............................... 42
8.2.2 Recommended Test Equipment ........................ 42
8.3 Transmitter Alignment Procedure ........................... 43
8.3.1 Injection Frequency Adjustment ....................... 43
8.3.2 Transmit Modulation Adjustment ........ 44
8.4 Receiver Aljgmnent ......................... 45
8.4.1 Receiver #1 Distortion and SINAD Alignment ............ 45
8.4.2 Receiver #2 Distortion and SINAD Alignment ............ 47
8.5 Diversity Reception Controller Alignment ..................... 49
8.5.1 RSSI Alignment for Receiver #1 ....................... 49
8.5.2 RSSI Aligmnent for Receiver #2 ....................... 50
8.5.3Receiver Audio Equalization ........................... 51
9.1 Transmitter Troubleshooting Flowchart ....................... 53
9.2 Receiver Troubleshooting Flowchart ......................... 54
9.3 Diversity Reception Controller Functional Troubleshooting
Flowchart ............................................. 55
9.4 Diversity Reception Controller Audio Level Troubleshooting
Flowchart ............................................. 56
GLOSSARY ................................................ 57
1 . INTRODUCTION
1.1 Document Scope
This document describes the ElectroCom Model DT450 mobile radio comprehensively
Section
Section
Section
Section
Section
nonAtechnical overview of the product and its features.
more detailed; describes various interfaces (i.e. connectors, power sources,
interconnections, etc.).
covers various specifications the product is designed to meet.
contains operating and maintenance instructions.
theory of operation, this section contains detailed functional descriptions of
circuit operation.
The remaining sections need no explanation.
Throughout this document, SMALL CAPITAL LETTERS are used to indicate signal names used
on schematics and italics are used when describing circuitry, methods, or devices which affect
regulatory compliance.
1.2
Reference Documents
Schematic Diagram, DT450 502-82006 Rev B (attached)
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Figure (7. Injection Synthesizer Functional Diagram
The injection synthesizer creates the receiver injection signals in the receive mode of
operation, and the transmit injection signal during transmit operation. Figure 7 is a
functional diagram of the DT450’s injection synthesizer section,
The receiver injection frequency is 45 MHz below the base station transmit frequency
The 450 MHz (nominal) signal from the VCO is applied to a divider. The divider splits this
signal into two equal amplitude signals. Each of these signals are further divided by two
additional dividers to produce a total of four equal amplitude injection signals Two of these
signals (RX INJECTION OUT 1 and RX INJECTION OUT 2) are used by the DT450’5
dual receivers in the receive mode. The receivers mix the injection signals (45 MHz below
the operating frequency) with the 450 MHz (nominal) received signal to produce a 45 MHZ
lF (Intermediate Frequency) signal,
The third RF signal (TX INJECTION OUT) is used by the DT450’s transmitter during
transmit operation Transmit modulation is applied to VCO as well as the 10 MHz reference
oscillator to produce FM modulation (reference the transmit processing section for more
detailed information). The TX INJECTION OUT signal is sent to the power amplifier section
21
for final amplification prior to transmission.
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Figure 8. Injection Synthesizer Functional Diagram (Repealed for reader conveniznre)
The fourth injection signal is used at all times by the digital frequency synthesizer to keep
the radio on channeli
The frequency synthesizer divides the injection signal to produce a quotient signal of 12.5
kHz. The synthesizer also divides the signal from the 10.0 MHz reference oscillator to
produce a 12.5 kHz signal. The synthesizer compares the phase of these two signals and
outputs a signal (PD OUT) proportional to their phase difference. A passive loop filter
converts the PD OUT signal to a DC control voltage which locks the VCO on channel.
In this manner, the VCO is compared to — and forced to emulate - the high—stability reference
oscillatorr This configuration is commonly referred to a: a digital Phase-LockedLODp (PLL)
frequency synthesizer.
22
5.4 Transmit Baseband Processing
TXMOD 07 vex
[DEV lAT lON cement.)
EXTVCD 0—D, E H - E F To vco
Eu==En EEssEt aucpza sums
LOW— pass
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(Low- rusouchv
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Figurefif Transmit Basebami Processing Functional Diagram
Figure 9 is a functional diagram of the DT450’s transmit baseband processing section.
The DT450 is capable of being modulated by an external device (control head, external
modem, etc.) or by the internal 4-1evel FSK modem. External modulation and internal
modem modulation are, at any one point in time, mutually exclusive,
External modulation (EXTMOD) from an external device (control head, external modem,
etc.) is buffered to provide load isolation and is then routed to a fourth»order Bessel low»
pass filter. The purpose of this filter is to remove any high—frequency components present
in the external modulation prior to application to the transmit modulator. Following the
filter, the external modulation is buffered to provide load isolation to the filter. The
modulation is routed though a summer and is applied to a VGA (Variable Gain Amplifier)
which provides transmit modulation deviation control.
The output of the first VGA directly modulates the VCO. This signal is also routed through
another VGA which provides low—frequency deviation control by modulating the reference
oscillator. This configuration is referred to as two-point modulation (with the VCO and the
reference oscillator being the two modulation points). Two point modulation prevents the
radio‘s PLL circuitry from counteracting the modulation process, and provides a clean flat
modulation response to the low frequency portion of the baseband spectrum,
4-1evel FSK modulation from the internal modem bypasses the Bessel filter as the modem
contains built—in filtering. This modulation is routed through the summer and is similarly
sent to the VCO and reference oscillator in the same manner as the external modulation.
23
5.5 UHF Receiver
The DT450 employs two independent, high»performance, low—noise, dual conversion FM
receivers The receiver is divided into two main sections, a front—end section and a 45 MHz
receiver section
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Figure 10, UHF Receiver Functional Diagram
24
5.5.1 UHF Front—End Section
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FRONT— END SECT ION
Figure 11. UHF Receiver Front~End Functional Diagram
Figure 11 is a functional block diagram of the receiver front—end section. The front~end
section employs an advanced-architecture cascaded-LNA (Low Noise Amplifier) design for
extreme sensitivity and high~overload performance.
Receiver input signals are first filtered by a preselector band-pass filter and are then romed
to a LNA. The amplified signal is routed through another bandpass filter (which functions
as a image/noise reject filter) to a second LNA. The output of the second INA is passed
through yet another bandpass filter.
The cascaded LNA configuration ensures a very low receiver noise figure which translates
to increased sensitivity. The cascaded band—pass filter configuration acts to sharpen the
filter’s frequency response skirts, thereby providing greater out»of—band rejection
performance.
After the final band-pass filter, the signal is applied to a mixer where it is mixed with the
receiver injection signal (45 MHz below the received signal) to produce a first IF
(Intermediate Frequency) of 45 MHZ. The 45 MHz IF is passed by a 45 MHz crystal filter
and is routed to the 45 MHz receiver section for further processing.
5.5.2 45 MHz Receiver Section
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Figure 12. 45 MHz Receiver Functional Diagram
Figure 12 is a functional block diagram of the 45 MHz receiver. The 45 MHz first IF from
the front-end is mixed with a 44.545 MHz injection frequency to produce a 455 kHz second
IF which is passed by a 455 kHz filter, The second IF is then amplified and limited by an
IF amplifier and limiting amplifier respectively. A 455 kHz filter provides interstate filtering
between the IF amplifier and the IF limiting amplifier.
This section includes the currentfto-voltage converters which produce the R851 signal (a DC
voltage proportional to the log of the received signal strength), The RSSI responds to signals
as low as »132 dBm and rises monotonically over a range of approximately 90 dB. RSSI is
used by the diversity reception system to select the best receiver at any particular point in
time.
The output of the limiting amplifier is applied to is tuned quadrature detector which outputs
recovered Frequency Modulation (FM).
26
5.6 Diversity Reception Controller
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Figure 13. DRC Functional Block Diagram
RECEIVER
SELECTOR
DlvERSlTY
AUDlO our
Figure 13 is a functional block diagram of the DRC (Diversity Reception Controller). The
DRC is the central processor of a dual-receiver diversity reception system. The DRC accepts
inputs from two receivers, determines which receiver has the better SNR (Signal to Noise
Ratio), and selects that receiver to supply recovered modlxlationi
High—speed RSSI from both receivers are processed by the RSSI input and RSSI level shifter
sections and are then forwarded to the receiver selector, and carrier detector sections The
receiver selector selects the appropriate receiver and the carrier detector provides a high—
speed indication of channel activity.
Recovered modulation from both receivers is processed by the recovered modulation input
and is sent to the recovered modulation switch which performs the actual selection process
as directed by the receiver selector.
27
The DRC is divided into 7 functional sections.
5.6.1 RSSI Input Section
| 4- l
SMlFYER
ausssu LowruAss BUFFER
FlLTEfl
Figure 14. RSSI Input Section Functional Diagram
Figure 14 is a functional diagram of the R551 input section of the DRC(for ease of
explanation, only one section is shown). RSSI from each receiver is buffered to provide
RSSI load isolation. Next, the buffered RSSI is low—pass filtered to remove high frequency
components (above the frequency of fade induced amplitude fluctuations). This improves
the diversity selection process at relatively low RF levels. Finally, the conditioned RSSI is
buffered again for isolation and forwarded to the level shifter for further processing.
5.6.2 RSSI Level Shifter
- - RSSl
“SN ‘Npu‘e———~‘ LEVEL SHlpTEp ———° LEVEL SHlFTED P551
Figure 15. RSSI Level Shifter Block Diagram
Figure 15 is a block diagram of me DRC’s RSSI level shifter (for ease of explanation, only
one section is shown). The purpose of the level shifter is to compensate for discrepancies
in RSSI and sensitivity between receivers. The RSSI level shifter essentially equalizes the
performance of the receivers. The level shifter contains an amplifier with adjustable slope
and adjustable threshold levels. The output of the level shifter is sent to the receiver selector
and carrier detector sections.
5.6.3 Receiver Selector
LEVEL SHIFTED R551 10__
——-—0 TO RECOVERED NDDULATlDN SWlTCH
LEVEL SHlFTED RSSl 201
COMPARATOR
Figure 16. Receiver Selector Functional Diagram
Figure 16 is a functional diagram of the DRC’s receiver selector. The receiver selector uses
levelfshifted R881 to select the appropriate receiver. In essence, the selector is a comparator
which will output one logic level if receiver 1 R851 is higher than receiver 2 RSSI (and will
output the other logic level otherwise). This section develops the control signal used to
actuate the recovered modulation switch.
5.6.4 Recovered Modulation Input
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Figure 17. Recovered Modulation Input Functional Diagram
Figurel7is a functional diagram of the recovered modulation input. Recovered modulation
from the receiver is first buffered to provide load isolation. This buffered signal is then sent
to a level adjust circuit which equalizes its amplitude. The signal is then high—pass filtered
to remove low-frequency components of the recovered signal (below the frequency of the
modulation). Finally, the signal is buffered for isolation and forwarded to the recovered
modulation switch.
29
5.6.5 Recovered Modulation Switch
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7\°—‘—-—c SELECT RECOVERED MODULATION
useovsnso NODuLATlDN 2 ,,__¢ (To DuTF’UT FINE“ SECTION)
Figure 18. Recovered Modulation Switch Functional Diagram
Figure 18 is a functional diagram of the DRC’s recovered modulation switch. This section
receives recovered modulation from both receivers as inputs. A control signal from the
receiver selector actuates the switch appropriately. The output of the switch is diversity
reception recovered modulation.
546.6 Carrier Detector
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Figure 19. Cam‘erDerector Functional Diagram
Figure 19 is a functiona diagram of the DRC carrier detector. The carrier detector receives
RSSI from both receivers A control voltage (from the receiver selector) continuously selects
RSSI from the selected receiver. This select RSSI signal is then low-pass filtered to remove
any switch induced transients and to improve performance at relatively low RF levels. This
signal is applied to a comparator. If the signal is above a reference value, the comparator
will generate a logic low indicating carrier activity. The threshold of carrier detect is factory
set to »107 dBm.
30
5.7 Receive Baseband Processing
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LOW- PASS
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D | SC AUD
(To MODEM)
Figure 20. Receive Baseband Processing
Figure 20 is a functional diagram of the receive baseband processing section.
DIVAUDIO (diversity audio) from the diversity reception controller is routed to two separate
paths, depending on whether the audio is destined for an external device (control head,
etemal modem, etc.) or for the internal 4-level FSK modem.
DIVAUDIO is routed directly to the internal modem as the modem contains internal filtering
of received signals.
For an eternal device, DIVAUDIO is routed through a 4800 Hz fourth-order Bessel low-pass
filter. The primary purpose of the filter is to improve the SNR (Signal to Noise Ratio) of
the recovered signal. Secondarily, the filter removes any transients induced by the high-speed
switching action of the diversity reception controller Following the filter, the signal is
buffered to provide load isolation and is routed to an external device as FDATA (filtered,
diversity recovered modulation).
31
5.8 Power Amplifier Module
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AMPLIF‘EF’ LOW—PASS Fi NAL Dwn AMPLiFlER
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Figure 21. Power Amplifier Functinnal Diagram
Figure 21 is a functional diagram of the power amplifier. The transmit injection signal from
the RF injection section is applied to a 1 watt amplifier. Following the amplifier, a 500 MHz
low—passfilterreduces spurious and harmonic emissions. The signal is then routed to the final
power amplifier which provides approximately 20 dB of gain, boosting the output signal to
40 Watts. This signal is routed to the T/R switch for transmission.
5.9 T/R (Transmit/Receive) Switch
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Figure 22. T ransmit/Receive Switch Functional Diagram
Figure 22 is a functional diagram of the T/R switch. The T/R switch enables one antenna
port to function as both a transmit port and as a receive port. A control signal TRSWCNTRL
is used to actuate the switch. The internal configuration of the T /R switch also attenuates
even—order harmonics.
32
6. RECOMMB‘IDED TOOLS AND TEST EQUIPMENT
6.1 Recommended Tools
Note
Ceramic tuning tool used to tune trimmer capacitors and poientiometers
Disengageinent 1001 44010008 used to disengage SSMT RF connectors
#0 Phillips screwdriver used for 0—80 sized screw fasteners on bottom cover
ll Phillips screwdriver used for 4-40 screws on and bottom cover and all PCB
mounting screws
£2 Phillips screwdriver used for 40 watt P.A. module removal and replacement
6.2 Recommended Test Equipment
_ Model
RF communication HP 8920 or equivalent
test 85!
Fluke 77 or equivalent
Oscilloscope 20 MHz BW
DC power supply 13.8VDC @ 10 Amps
t DT Series test box | ECS PIN 502-8203!)
used to measure RF output power, frequency error,
SINAD, audio level out, disronion, etc.
used for test point voltage measurements
audio stage gain measurements
main DC input power for the DT450
convenient test box for miscellaneous rest functions
33
7 INSTALLATION
7.1 Unpacking and Inspection
Carefully unpack the data radio. It is recommended you verify the items shipped match the
items ordered before discarding the packing material Standard and optional items are listed
below. If any damage has occurred during shipment, file a claim with the carrier
immediately.
Standard Equipment:
0 DT450 Mobile Radio with mounting brackets attached
0 Mounting hardware (4 ea number 10 self tapping screws)
- Power cable pigtail with fuse holder and ground lug
Optional Equipment:
0 Heavy-duty noise filter
0 Microstrip patch antenna
34
7.2 Installation Instructions
It is recommended the installation be performed by qualified technicians familiar with two-
way mobile radio installation procedures. Contact your sales representative for a list of
authorized installation facilities in your area.
CAUTION
Automotive Electronics RF Susceptibility - Certain automotive electronic systems
such as ABS (Anti-Skid Braking) systems, electronic fuel injection systems, electronic
cruise control systems, electronic entertainment systems, etc. may be adversely
affected by RF energy during transmit operation of the radio. If radio is to be
installed in a vehicle using these types of electronic systems, consult the automobile
manufacturer for any precautionary measures required to avoid adverse operation of
these electronic systems.
”
7.2.1 Equipment Requirements
The following equipment is required to perform the installation.
0 Electric screw gun for self-tapping screws
0 #2 Phillips screwdriver for mounting bracket screws
- Crimping tool for power cable
0 Crimping tool for anteruia connections
35
7.2.2 Instaflation Procedures
Prior to installing the radio, it is recommended you ensure the following conditions are
satisfied:
0 The radio will be sewrely mounted in a safe location (ensure the radio will not
become a projectile in the event of a collision)
The radio will be located in an area free from standing water
The radio will be located in an area easily accessible to the radio technician
The radio will be located in an area which will not obstruct any automotive
mechanisms
The radio will be installed in a neat and proper fashion
CAUTION
Before installing the self-tapping screws, check the opposite side of the mounting
surface and ensure adequate clearance exists for the full length of the screw Ensure
no possibility of penetration into any vital system (brake lines, fuel tank, etc).
36
The radio may be mounted vertically or horizontally. The position of the interface connector
and the antenna connectors should always be considered carefully (right-angle antenna
connectors can reduce the space requirements). Cables should be routed in a manner which
ensures the cables will not be pulled or damaged in any way by cargo or passenger feet or
any other mechanism
The supplied quickAdiscomlect power pigtail has a red lead terminated into one end of an
in—line fuse holder; the other end of the fuse holder is left un-terminated. Optional noise
filters are recommended. All cabling in the vicinity of the radio should have enough slack
to allow the radio to be serviced with the power connected if required. A typical installation
diagram is depicted below.
37
WARNING
FCC regulations require that the frequency and deviation of a transmitter must be
checked before it is placed into service and re-checked at one year intervals
thereafter
FCC regulations also state that the RF output power of a radio transmitter shall be
no more than that required for satisfactory operation considering the area to be
covered and local conditions.
FCC ID number for the DT450 Transmitter: ECSDT450TX
_————————————
__—__—_—_————
WARNING
Vehicles powered by Liquified Petroleum gas (LP gas) with the gas container in the
trunk or other sealed-off space must conform to National Fire Protection Association
Standard 58 requiring:
0 Space containing radio equipment shall be isolated by a seal from the space
containing the LP gas container and its fitting.
0 Outside filling connections shall be used for the LP gas container.
0 The LP gas container space shall be vented to the outside of the vehicle.
38
7.3 Antenna Considerations
In general, the most important part of a radio is the antenna. This is particularly of the dual
receiver. dual RF port, DT450. The unique architecture of the DT450 enables considerable
operational flexibility;however, closely spaced antennas, and controlled antenna correlation
require careful consideration. It is not practical to cover all possible situations; therefore,
this section should be used as a guide to proper antenna configuration practices.
7.3.1 Antenna Radiation Pattern
In the mobile environment, the RF energy is as likely to come from one direction as any
otheri Therefore, an omnidirectional horizontal antenna radiation pattern is required
An omnidirectional horizontal pattern precludes horizontal gain; therefore, antenna gain
must be realized in the vertical dimension. Producing antenna gain in the vertical axis is
problematic at the mobile unit.
As the gain of an omnidirectional antenna is increased, the vertical beamwidth is reduced.
In areas where line of sight conditions between transmit and receive antennas do not exist,
the vertical angle of arrival of energy is as likely to be from one angle as any other (this is
especially true of urban areas and areas with heavy topographic relief). In this situation, a
high gain antenna (with narrow vertical beamwidth) will not perform as well as a low gain
antenna (with a wider vertical beamwidth) because much of the energy is arriving at from
an elevation angle in excess of the vertical beamwidth of the high gain antenna. For this
reason. antennas with greater than 3 dB gain should not be used in the mobile environment.
7.3.2 Antenna Near—Field Exclusion Zone
For most omnidirectional mobile antennas, as the gain of the antenna is increased, the
length of the radiating element is also increased. This becomes problematic when one
considers the fact that the antenna near—field exclusion zone (the area surrounding an
antenna which must be kept free from objects) is proportional to the square of the length
of the longest radiating element. Specifically, in order to avoid antenna radiation pattern
perturbations, the area surrounding the antenna must be free from conductive or reflective
39
objects (including other antemias) by a distance equal to the antenna’s near field given by
the following formula:
F" 1 2m?
where: F,I is the near field radius in inches,
d is the length of the radiating element in inches,
and A is the wavelength in inches.
For example, a 5 dB gain antenna with a length of 33 inches will require an area free from
objects extending 57 inches from the antenna in all directions, Locating two such antennas
on the roof of an automobile, with an adequate ground plane surrounding each antenna is
not normally possible.
The near»field exclusion zone of a unity gain quarter-wave antenna, with a vertical radiator
length of 6.5 inches is less than 3.5 inches. This spacing requirement is easily achievable, but
at the cost of 3 dB of gain
7.3.3 Antenna Correlation Coefficient
One final parameter of concern is related to the separation of diversity reception antennas.
The lower the correlation between diversity antennas, the higher the diversity gain. Field
tests have determined the separation distance which produces the smallest correlation
coefficient is 0.8 wavelengths (21 inches at 450 MHz). Clearly, this is inside the near—field
exclusion zone of the 5 dB gain antenna.
7.3.4 Wrostrip Patch Antennas
One antenna which satisfies the above criteria quite well is the microstrip patch antenna
A circular patch antenna can produce 3.0dB gain with the longest radiating element being
5.5 inches. This results in a near-field exclusion zone of only 2.3 inches. This allows the .8
wavelength separation without violating the near-field exclusion zone. The antenna’s physical
orientation (no vertical radiator) has several other benefits related to protecting the antenna
from willful or accidental damage.
8. MAINTENANCE AND ALIGNMENT PROCEDURES
8.1.1 Test Equipment Setup
SERVICE
MONITOR
PDWEQ
SUPPLY
13 BVDC
15A
RADlO sw9~
DT nADlD
(Bottom)
Figure 25. Test Equipment Setup
The typical test equipment setup is illustrated inFigure 25. and should be used to perform
functional tests and alignment procedures.
It is recommended the troubleshooting flowcharts be used as the first step in verifying
proper radio operation.
41
8.2 RECOMMENDED TOOLS AND
8.2.1 Recommended Tools
00010000
40010000
I“) Phillips screwdriver
# 1 Phillips screwdriver
#2 Phillips screwdriver
8.2.2 Recommended Tm Fquipment
TEST EQUIPMENT
used to time trimmer capacitors and potentiometers
used to disengage SSMT RF connectors
used for 0»80 sized screw fasteners on bottom cover
used for 4—40 screws on and bottom cover and all PCB
mounting screws
used for 40 watt P.A. module removal and replacement
Item Model
Note
RF communication HP 8920 or equivalent
test set
DMM Fluke 77 or equivalent
20 MHz BW
13.svoc @ 10 Amps
lacs P/N soz-szoso
Oscilloscope
DC power supply
DT Series test box
used to measure RF output power, frequency error.
SINAD, audio level out, distortion, etc.
used for test point voltage measurements
audio stage gain measurements
main DC input power for the DT450
convenient test box for miscellaneous test functions
42
8.3
”Swan” u- i
H WU~EEL_ ©
53
Do
59 s
a.
as
so
6° . m
S ‘ n ?
u...” .m =
O um'. 5+—
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El“!
Emu:
c em
a l...
53 ‘
‘ ~ seal M game
f RV2
Figure 26‘ Transmit Adjustment PCB Location:
8.3.1 Injection quuency Adjustment
3. Select one of the six radio channels (0, 1, 2, 4, 8, or 16) with the DT series test
box and key the radio with the "FIT” switch.
bi Using ceramic tuning tool, adjust Y3 for minimum frequency error.
43
mmmn
1m!
5 a
nunllln
7 RVZ
Figure 27. Transmit Adjustment PCB Locations (reptaledfizrreadzrmnvenimce)
8.3.2 Tmnmuit Modulation Adjustment
a. Inject a 1.0 Volt peak-to—peak 10 kHz audio test tone into "TX AUD“ on DT
series test box.
bl While monitoring the service monitor, adjust potentiometer RV2 for required
system deviation.
c. Inject a 1.0Volt peak—to-peak 100 Hz audio test tone into "TX AUD" on DT series
test box.
d. While monitoring the service monitor, adjust potentiometer RV1 to the same
deviation as in step b.
Note: RV1 and RVZ are interactive adjustments; therefore, repeat steps b through
e until further adjustments are no longer required.
44
8.4 Receiver Alignment
WHnml
cocoonor
uaaoeo-o
m mac-ans
Figure 28. Receiver #1 Adjustment PCB Locations
8.4.1 Receiver #1 Distortion and SENAD Alignment
a. Manually select receiver #1 and monitor "RX AUD" using DT series test box.
b. Inject an on—frequency RF carrier signal at a level of -80 dBm modulated with a
1.0 kHz test tone at +/- 4.0 kHz into receiver #1 RF port 12.
c. Adjust trimmer capacitor CV2A to the center of its tuning range (reference
schematic sheet 7).
d. Altemately adjust trimmer capacitors CVlA and CVSA for the lowest attainable
distortion (3% maximum, 1,5% typical). If distortion can not be adjusted to less than
3%, CV2A may be used to improve the distortion by rotating CV2A +/- 1/4 turn
from its center position.
45
mnmlm
i a
”Hut
ooanm-mmanma.
oeessaemaaso-
Figure 29. Receiver [fl Adjustment PCB Locations {repzatedfar rtndtrconvmimre)
e. While monitoring the DC voltage at USA pin 7,carefully adjust FT4A, then FT3A,
then FT2A for maximum DC voltage at USA pin 7 (typically 2.6VDC).
f. Reduce the RF level and verify minimum 12 dB sensitivity is within specification.
g. Record 12 dB SINAD RF level for DRC alignment purposes.
Note: DRC (diversity Reception Controller) alignment procedure Section m must
be performed after completing the above procedure.
FLT4E
Figure 30. Receiver #2 Adjustment PCB Locations
8.4.2 Receiver in Distortion and SINAD Alignment
.a. Manually select receiver #’2 and monitor "RX AUD" using DT series test box.
I). Inject an on-frequency RF carrier signal at a level of -80 dBm modulated with a
1.0 kHz test tone at +/— 4.0 kHz into receiver #2 RF port 13.
c. Adjust trimmer capacitor CV2B to the center of its tuning range (reference
schematic sheet 12).
d. Altemately adjust trimmer capacitors CVlB and CV3B for the lowest attainable
distortion (3% maximum, 1.5% typical). If distortion can not be adjusted to less than
3%, CVZB may be used to improve the distonion by rotating CVZB +/- 1/4 mm
from its center position.
47
USE? 7
FLT4B
CVBE
lmum
unumau.
mutaoaal
if
E-
$5”
Figure 31. Receiver #2 Adjustment PCB Locations {Repeated/ivrmdercanvmienu)
e. While monitoring the DC voltage at USB pin 7, carefully adjust FT4B, then FT3B,
then FTZB for maximum DC voltage at U8B pin 7 (typically 26 VDC).
fl Reduce the RF level and verify minimum 12 dB sensitivity is within specification,
g. Record 12 dB SINAD RF level for DRC alignment purposes.
Note: DRC (diversity Reception Controller) alignment procedure Section XXX must
be performed after completing the above procedure.
8.5 Diversity Reception Controller Alignment
R11D
9143 TF"!
Figure 32. R551 Alignment for Receiver #1 PCB Adjustment Locations
8.5.1 RSSI Alignment for Receiver #1
Note: Receiver sensitivity must be measured and recorded in order to perform this
alignment procedure.
a. Inject an on—frequency, urn—modulated RF carrier to RF port 12 with an
amplitude equal to receiver #1‘5 12 dB SINAD level.
b. While monitoring TPl, adjust R110 to attain a level of 0.50 VDC at TPl
(reference schematic sheet 13 C7).
cl Increase the RF carrier amplitude by 50 dBm.
d. While monitoring TPl, adjust R143 to attain a level 012.50 VDC at TPl
(reference schematic sheet 13 C7).
e. Adjustments R110 and R143 are interactive adjustments; therefore, repeat
steps a through d until further adjustments are no longer necessary.
49
8.5.2 RSSI Alignment for Receiver #2
TPZ
nun-mu
Figure 33. RSSI Alignment for cheiver #2 PCB Adjustment Locations
Note: Receiver sensitivity must be measured and recorded in order to perform this
alignment procedure.
a. Inject an 0n~frequency, tan-modulated RF carrier to RF port 13 with an
amplitude equal to receiver #1’5 12 dB SlNAD level.
b. While monitoring TPl, adjust R109 to attain a level of 0.50 VDC at TPl
(reference schematic sheet 13 D7).
c. Increase the RF carrier amplitude by 50 dBm.
dt While monitoring TP2, adjust R108 to attain a level of 2.50 VDC at TP2
(reference schematic sheet 13 D7).
e. Adjustments R109 and R108 are interactive adjustments; therefore, repeat
steps a through d until further adjustments are no longer necessary.
8.5.3Receiver Audio Equalization
Rfl47
9149
'-
as
can
Figure 344 Receiver Audio Level Equalization PCB Adjustment Locations
3. Using DT series test box, select "auto“ and monitor receiver audio at
"RX AUD".
b. Adjust R147 and R149 fully clockwise
c. Inject an on—frequency RF signal at a level of —80 dBm, modulated with a 140
kHz test tone at a level of +/- 4.0 kHz deviation into RF port 12 (receiver #l).
d. Record receiver audio level.
e. Inject an on—frequency RF signal at a level of -80 dBm, modulated with a 1.0
kHz test tone at a level of +/- 4.0 kHz deviation into RF port 13 (receiver #2).
f. Adjust the higher of the two levels to equal the amplitude of the lower level
(adjust R147 for receiver #1 and R149 for receiver #2, reference schematic sheet
13 B3).
51
Troubleshooting Flow Charts
52
9.1 Transmitter Troubleshooting Flowchart
TRANSM\TTEQ FUNCT‘ONAL TEST
START
APPLY 1m; 11 1v==
YEST TONE m ”(x ADD
pom ON 97 YES? sax
ws Yx EnEauEmcv
mmm 12nnHz DE
ASSIGNED FHEDUENEV
WHEN KEVED7
NO ADJUST v3
REFER To sEcnoN a z
5 1x NonuLATwo
wleN nEoumED
SYSYEM DEVIAT‘DN’
NOTE v REYURN Eon
“crow sEnva
IF oEEEcmvE
NO ADJUSY av?
REFER m 5Ecmo~ s 3
APPLY man: 9 was
TEET TUNE YD ‘Tx Auov
pony o~ ov TEST Box
ws 7x vacuums
THE SAME A5 1m:
YEST TONE nEvmmuN
ADJUST mm
nEEEw m sEcnoN a 3
rs Tx powEn 70
Spec WNEN KEVEU a
rumsm TrEa on:
53
9,2
Receiver Troubleshooting Flowchart
QECE J VER FUNCT \ ONAL TEST
START
SELECT nx—T
AND leTDR “Rx AUD'
ON DT TEST sox
MEASURE HECEWEH u
1235 szAD
AND DWSTDETWON
ws ngcgwsn 11
SENSlTlleY To 595: 3
ND
NoT E
~=EEFOQM DFIC AUGNMENT
5.5an To sEcTwoN e s
’
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PDF Version                     : 1.3
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Create Date                     : 2001:06:21 08:28:48
Producer                        : Acrobat Distiller 4.0 for Windows
Author                          : jsoscia
Title                           : 40674.pdf
Modify Date                     : 2001:06:21 08:28:50-04:00
Page Count                      : 64

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