Dataradio Paragon, Техническое руководство

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120 20170-204a Paragon
PD
Technical Manual
47
6.4.2.2 Synthesizer Alignment
Single channel: Connect the multimeter to either side of L504 (T885) or the long lead of L1 (T855
and T835) in the VCO (this measures the synthesizer loop voltage).
1. T885 (800/900 MHz) Tune VCO trimmer CV500 for a synthesizer loop voltage of 10V DC.
2. T855 (UHF) Tune VCO trimmer C6 for a synthesizer loop voltage of 10V DC.
3. T835 (VHF). Tune VCO trimmer CV1 for a synthesizer loop voltage of 9VDC.
Multiple channels (adjusting as shown for single channel above):
1. T885 (800/900 MHz) Adjust the VCO loop to 10V using the middle frequency channel.
2. T855 (UHF) Adjust the VCO loop to 10V using the middle frequency channel.
3. T835 (VHF) Adjust the VCO loop to 9V using the middle frequency channel.
4. All channels should lie within the upper and lower limits of respectively
All channels should lie within the upper and lower limits of 16V and 3V respectively for the T885
and T855 or within 13V and 5V for the T835.
6.4.2.3 Front-End Alignment
1. IFR COM120B settings:
a) Connect a 3 feet long double shielded cable (N-M to BNC-M) between the IFR T/R output
and the receiver antenna connector.
b) Select the generator mode (GEN button) and set to the main receiver channel frequency
c) Select and turnon GEN2
d) Set the FM Deviation to ±3kHz (full channel) or ±1.5kHz (half channel) using 1KHz sine
e) Select SINAD meter
f) Use a X1 scope probe connected to SINAD input and monitor the Discriminator O/P on the
backplane at SK1 pin 6 (RX-audio1). Alternately, it is also possible to monitor at the receiver
I/O Pad P207 (T885), the receiver TP314 (T855) or at the receiver IC350 pin 7 (T835).
2. Adjust the helical resonators for best SINAD: #H400, #H401 and #H900 (T885); #FL410 and
#FL420 (T855) or L410, L420, L460 and L470 (T835).
3. Continually decrease the RF level to reach 12dB SINAD, then re-do step 2) & 3) again. (mini-
mum requirement to reach is 12dB SINAD for -110dBm)
4. Perform the SINAD linearity tests described in paragraph 6.4.2.4. If it fails to pass the require-
ment, contact your Dataradio technical support.
WARNING: Do NOT attempt to re-tune the IF stages
(I.e. L300 and L301 for T885, L310 to L390 for T855 or L330 to L360 and
CV318 for T835).
These adjustments do not need to be re-adjusted after frequency re-programming.
Touching these coils will have a direct impact on the modem DSP coefficient set-
tings and may reduce significantly the radio performances over data.
6.4.2.4 SINAD and Linearity Check
1. Apply the following settings to the IFR:
a) Generator mode, Output T/R