User's Manual Chapter 5

§ Oscilloscope
§ +13.8VDC power supply
Preliminaries:
¯ Program upper, middle and lower frequencies of band (refer section 5.4 for band
split details) into 3 channels in MXTOOLS channel screen ( Note that 'Continuous
Update Enabled' on the MXTOOLS channel screen should be ticked for these
tests).
¯ Remove top cover from Receiver module under test and fit known working VCO
tuned for the band to be tested ( refer section 4.5).
¯ Connect Receiver to working Micro Controller via 16-way ribbon cable.
Procedure:
The test procedure for the Receiver is divided into the front end alignment and the IF
alignment procedures
Front End Alignment:
I. Switch DC power on. Check that the output voltage on pin I of IC8 is 5V +/- 0.2V,
on pin 1 oflC2 is 8V +/-0.2V, on output of IC9 (on C66) is 8V +/- 0.2V and on pin 1
oflC3 is 9V +/- 0.2V.
2. Remove jumper E and D. Install jumper C. Connect tracking generator output to CN1
and spectrum analyser input to CN4. Set tracking generator to sweep the band.
Adjust A4, A 10 and A 16 for a symmetrical passband around the band center
frequency. Check that the gain over the band is 12dB and that the ripple is <+/-
1.5dB. Check that the attenuation at the first IF image is >50dB.
3. Remove jumper C and I. Install jumper E and H. Connect tracking generator output
to CN4 and spectrum analyser input to CN5. Set tracking generator to sweep the
band. Adjust B4, B10 and B16 for a symmetrical passband around the band center
frequency. Check that the maximum loss over the band is < 3dB and that the
attenuation at the first IF image is >50dB.
4. Remove jumper E. Install jumper D. Connect spectrum analyser input to CN5 and
tracking generator output to CN1. Set tracking generator to sweep the band. Check
for symmetrical passband around band center frequency. Check that the gain over the
band is 10dB and that the ripple is <l.5dB. Remove Jumper H. Install Jumper J.
IF Alignment:
1. Select the mid channel. Check that LD on SKD-16 goes high indicating that the
synthesizer is in lock. Remove S3 (0gl local oscillator connection to mixer) and
solder a 500 coax test lead across C60 position ( note C60 position is near a retaining