User Manual

SECTION 2: FACTORY TEST PROCEDURE
IP4HPVGPS-MRFCCRpt.doc Page 12
Receiver 2
Perform the following steps to adjust receiver 2:
Step 1 Inject an on-frequency carrier signal with an amplitude of -80 dBm, modulated with a 1 kHz
test tone at +/- 5.0 kHz deviation into Receiver 2's antenna port.
Step 2 While monitoring the voltage at RSSI2 Test Point with a DMM, adjust trimmer capacitor CV4
to midway between the points where the oscillation stops.
Step 3 While monitoring the DC level of the recovered modulation, adjust potentiometer R99 for a
reading of 350 mV (+/-10 mV) RMS.
Step 4 While monitoring the amplitude of the recovered audio signal, adjust potentiometer R93 for a
reading of 2.500 (+/-10 mV) VDC.
Step 5 Steps 3 and 4 are interactive adjustments, therefore repeat steps 3 and 4 until further
adjustment is no longer required (i.e. when 350 mV RMS and 2.500 VDC are realized).
Step 6 While monitoring the recovered audio signal at TP1, verify the distortion is less than 3%,
adjust CV4 if necessary to achieve less than 3% distortion. Record this value on the Test
Data Sheet.
Step 7 While monitoring the recovered audio signal at TP1, verify the SINAD is -118 dBm or better.
Record this value on the Test Data Sheet.