Specifications

5–10
FM500 User's Manual
5.19.1 Main Channel Into Sub
Feed the left and right channels in phase with audio (L+R) at 50 Hz, 100 Hz, 400
Hz, 1 kHz, 5 kHz, 10 kHz, and 15 kHz at 100% modulation, while observing the
stereo subcarrier (L-R) level on an FM modulation monitor.
5.19.2 Sub Channel Into Main
Feed the audio into the left and right channel as above, with the exception of
reversing the polarity of the audio of one channel (L-R input). Using the
frequencies of 5.19.1 above, observe the main channel (L+R) level with a
modulation monitor.
5.20 38 kHz Subcarrier Suppression
With no modulation, but in the Stereo mode, the 38 kHz subcarrier, as indicated on
an FM modulation monitor, should be down at least 40 dB.
5.21 Additional Checks
In addition to the tests and adjustments mentioned in this section, the following
checks ensure a complete performance appraisal of the transmitter:
1. Perform a physical inspection, looking for visible damage and checking that
the chassis hardware and circuit boards are secure.
2. Check the functionality of switches and processing control.
3. Verify that all indicators function.
4. Check the frequency synthesizer lock at 80 MHz and 110 MHz.
5. Measure the AC line current with and without the carrier on.
6. Perform a functional test of the SCA input, Monitor outputs, and the monitor
and control function at the 15–pin, D-sub connector.
7. Test the functionality of the FSK circuit.
8. Check the operation and timing of the automatic carrier-off circuitry associ-
ated with program failure.
9. Check all metering functions.
10. Test ALC action with PA current overload, SWR, and PLL lock.
NOTE:
FCC type acceptance procedures call for testing the carrier frequency over the
temperature range of 0–50 degrees centigrade, and at line voltages from 85% to
115% of rating. (See FCC Part 2.995.)