AES 7085VE5 Users Manual
52-7085VE5
VHF
DATATRANSCEIVERS
PLL SYNTHESIZED (EEPROM)
Service Manual
TABLE OFCONTENS
1. SPECIFICATION … … … … … … … … … … … … … … … … … … … … … … … … … ..
2. CONNECTIONS AND OPERATION… … … … … … … … … … … … … … … … 3
3. CIRCUIT DESCRIPTION … … … … … … … … … … … … … … … … … … … … ..4-10
4. PERFORMANCE TEST AND ALIGNMENT… … … … … … … … … … … 10
5. TEST EQUIPMENT CONFIGURATION … … … … … … … … … … … … … 11
6. TRANSMITTER PERFORMANCE TEST … … … … … .… … … … … … … … … .12-13
7. PARTS LIST … … … … … … … … … … … … … … … … … … … … … … … … … … ..14-22
8. PROGRAMMER INSTRUCTION… … ..… … … … … … … … … … … … … … … .23-28
9. PARTS ASSEMBLY … … … .… … … … … … … … … … … … … … … … … … … … .29-30
2
10. BLOCK DIAGRAM … … .… … … … … … … … … … … … … … … … … … … … … 31
11. SCHEMATICS DIAGRAM… … … … … … … … … … … … … … … … … … … … 32
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1. SPECIFICATION
GENERAL SPECIFICATIONS
PERFORMANCE SPECIFICATIONS … … … … … … … … … ...FCC PART 90
POWER SOURCE … … … … … … … … … … … … … … … +13.6VD.C. nominal(+10.8 to +15.6V )
TEMPERATURE RANGE
STORAGE … … … … … … … … … … … … … … … .80℃ maximum -40℃ min.
25℃ nominal
OPERATING … … … … … … … … … … … … … … .60℃ maximum -20℃ min.
ANTENNA IMPEDANCE … … … … … … … … … … … … ...50Ω
FREQUENCY CONTROL … … … … … … … … … … … … … ...PLL SYNTHESISER
FREQUENCIES OF OPERATION … … … … … … … … … .136~165 , 146~174MHZ
FREQUENCY TOLERANCE AND STABILITY… … … … ±1.5PPM
MODULATION TYPE … … … … … … … … … … … … … … … .FM
INTERMEDIATE FREQUENICES … … … … … … … … … … .21.4 MHZ
455 KHZ
CHANNEL SPACING … … … … … … … … … … … … … 12.5 /25KHZ
TRANSMIT ATTACK TIME … … … … … … … … … … ＜25 mS
HIGH HUMIDITY … … … … … … … … … … … … … … … … .90﹪
CHANNEL CAPABILITY … … … … … … … … … … … … … .16 by software control
NOMINAL DIMENSIONS … … … … … … … … … … … … … .134 ㎜(L)X60 ㎜(W)X33 ㎜(H)
WEIGHT … … … … … … … … … … … … … … … … … … … … … .145g
RADIO DATATRANSCEIVER NOMINALPERFORMANCE
TEST FREQUENCY-------------------------------------------------142.0125MHZ
RECEIVER TEST AT 12.5KHZ CHANNEL SPACING
1. Audio Level (0.3~0.5V) ----------------------------------------245mV
2. Distortion (＜ 5%)--------------------------------------------2.3%
3. SINAD (> 12dB at –119dBm)----------------------------15dB
4. Current ---------------------------------------------------------------90mA
5. Carrier Detect Level--------------------OFF: -114dBm ON:-116dBm
TRANSMITTER TEST AT 12.5KHZ CHANNEL SPACING
1.RF Output Power(5.0~6.5W)--------------------------------------5.5W
2.Current (＜1300mA)------------------------------------------------1180mA
3.Deviation (1.7~2.1 khz at 106mV)---------------------------------1.9khz
4.Distortion (＜ 5%)---------------------------------------------------0.9%
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2. CONNECTIONS AND OPERATION
PIN
FUNCTION
TYPE
RANGE
DESCRIPTION
EXTERNAL CONNECTIONS
1-
50Ω BNC SOCKET
2-
9 WAY 〝 D 〞TYPE PLUG(J501)
D-TYPE INTERCONNECTIONS
J501-1 DATA_IN ANALOGUE 106mV EXTERNAL MODULATION INPUT
J501-2 DATA_OUT ANALOGUE 250~350mV RECEIVER AF OUTPUT
J501-3 PTT INPUT 0V/+5V TRANSMIT ENABLE
J501-4 GND GND 0V GND
J501-5 B+ V+ +13.8V POWER SUPPLY
J501-6 CDS OUTPUT OPEN/SHORT RF CARRIER DETECT
J501-7 RSSI OUTPUT 1.2V~2.3V RSSI OUTPUT
J501-8
J501-9 PGM_ENB INPUT 0V/5V PROGRAMMING ENABLE
PGM_DATA
INPUT 0V/NC PROGRAMMER DATA INPUT
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3. CIRCUIT DESCRIPTION
TRANSMITTER
The transmitter is comprised of:
• Audio amplifier connections from J501 pin 1
• Frequency Synthesizer
• Transmitter
• Automatic Power Control
Audio frequency connections
Processed data from the U602 is applied to the VCO via R621
and applied to the TCXO VC
Frequency synthesizer circuit
With data received from the EEPROM (U503) the frequency synthesizer circuit controls and
Produces the RF carrier frequency for the transmitter during transmit and the local oscillator
frequency for the receiver. The frequency synthesizer circuit is comprised of:
• 12.8 MHZ Tcxo
• Voltage Controlled Oscillator (VCO) module
• Charge Pump and Loop Filter
• PLL Frequency Synthesizer
• Dual Modulus Prescaler
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PLL Synthesizer
The module contains RX VCO and TX VCO . TX VCO for producing carrier frequencies during
The PLL synthesizer circuit is common to both the transmitter and receiver,
The synthesizer comprises:
Data
TCXO
U401
PLL
5V
Regulator
Loop Filter
Charge Pump
TX OR RX
VCO
RF Out
12.8 MHZ TCXO
X401 is VCTCXO , which provide stable oscillator of 12.8 MHZ to PLL IC.
Frequency adjustment is provided by VR401
.Voltage controlled oscillator module(VCO)
The module produces carrier frequencies during transmit and local oscillator frequencies during receive.
Transmit and RX VCO for producing the local oscillator frequency during receive .
The module also has Rx and TX powerline filters.
RX and TX power line filters
Transistor Q306 is configured as a 5v power supply ripple filter. The filter reduces the noise on the carrier and
local oscillator signals.
PAGE5
RX
VCO
The RX VCO comprises JFET Q301, coil L302 , and varactor D301 and is configured as a Colpitts Oscillator .
D301 produces a change in frequency with a change in DC voltage and is controlled by the tuning voltage signal
present at the cathode. The local oscillator signal at the source of Q301 isa pplied to the buffer/amplifier formed
by Q305 and Q201.The Local signal is applied to the mixer when diode D203 is reverse biased and D202 is
forward biased.
TX VCO
The TX VCO comprises JFET Q302,coil L305 , and varactor D302 and D303 and is configured as a Colpitts
oscillator . D302 produces a change in frequency with a change in DC voltage and is controlled by the tuning
voltage signal present at the cathode. The AF signal at J901 pin 1 is applied to the cathode of D303 to produce
FM modulation. When diode D203 is forward biased and D202 is reversed biased the modulated RF signal at the
collector of Q201 is passed to the power Amplifier and harmonic filter via the cascode buffer/amplifier Q205.
PLL IC
The reference frequency from the TCXO, at 12.8 MHZ , is connected to pin 1 of U401(MB1504) the appropriate
VCO is connected to pin 11.
REFDIV divides the 12.8 MHz to produce a reference frequency (Fr) of 5 or 6. 25 kHz dependent upon channel
spacing selected. VARDIV divides the prescaled VCO frequency to produce a variable frequency (Fv). Fv and Fr
are fed to the phase detector.
Phase detector
When Fv=Fr, the phase detector output (pins 15 and 16,U401) produces narrow negative pulses and Fv and Fr
pulse widths are identical. When Fv〉Fr pin 15 (V) pulses negative with pin 16(R) remaining high.
When Fv〈Fr pin 16 (R) pulses negative with pin 15(V) remaining high.
The signal at pin 15 and 16 is smoothed the loop filter and applied to the VCO.
Out-of-lock detector
The out-of-lock detector produces a series of logic level pulses when the loop is out of lock at pin 7 of U401.The
pulses at pin 7 of U401 are buffered by Q401 and then integrated by R407 and C406. The product of the
integrating circuit is fed to Q202 to turn off transmitter power.
Charge Pump and Loop Filter
Transistors Q402~Q404 , and associated resistors and capacitors form the charge pump and loop filter .
The phase detector output from U401 pins 15 and 16 are combined by the charge pump to produce a 0 to 8V
tuning voltage signal.
The signal is filtered by the loop filter (R414,C414 and C413) to remove any residual reference frequency
harmonics from the signal. After filtering the signal is applied to the voltage controlled oscillator module.
PAGE6
DC REGULATOR
The DC Regulator U402, converts the +13.6 V to a 5V supply .
This is used to provide the tuning voltage for the VCO .
Dual modulus prescaler
The prescaler divides the VCO frequency by 64 or 65.
Transmitter
The transmitter comprises:
VCO Buffer PA Module
Amp
RF LPF
Automatic
Power Control
ANTENNA
SWITCH
Buffer
When the radio is in transmit mode the diode D203 is forward biases enabling the modulated RF signal
from the VCO to pass to the buffer/pre-amplifier Q205 and associated components.
The output signal is passed from Q205 to Q206 via a matching network consisting of inductor L203 and
C217.
PA module
The signal is then amplified for transmission by 207, which is a power amplifier module.
Low pass filter
The amplified RF signal is passed through the stripline coupler and is fed to the harmonic low pass filter,
comprising L211 to L212 and C228-C240 and then to the antenna connector (ANT).
Antenna Switch
When transmitting, the diodes D205 are forward biased, allowing the RF to pass to the antenna. D206 is
shorted to ground which makes L210 look open circuit (1/4 wave tuned stub). This prevents the TX signal
from passing to the receiver stage.
Power output control .
The RF power tuning by VC201,which make sure the current less than 1300mA when output power is 5 W.
PAGE7
Receiver
The receiver comprises:
Rx
VCO
SAW FILTER&
ANTENNA
SWITCH
IFAmp
Amp
First Mixer
Second
Mixer
Local
Oscillator
IF Filter
IF
Filter
Data Out
Audio Filter
FM
Limiter-
Discnminator
Squelch
Circuit
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