Audio Power Output Test - Motorola R-2001D Operator's Manual

SQUELCH SENSITIVITY TEST
1. Connect the Analyzer to the receiver under test, as shown in figure 4-3. Set DISPLAY to Oen/Mon Mtr, FUNCTION
switch to Generate FM, and enter the frequency of the receiver under test.
2.
To check PLlDPL squelch sensitivity, enter the proper PLlDPL code from the keypad. Set MODULATION switch
to Cont in the PLlDPL Mode.
3. Adjust the Code Synth Level control to provide a nominal 750 Hz (500 Hz - 1 KHz) deviation of the PLlDPL code.
To check carrier squelch, turn off all modulation.
4.
Place FUNCTION switch to monitor to remove the RF output from the receiver. Set the receiver's squelch control to
the point where the receiver just barely quiets.
5.
Return FUNCTION switch to Generate. Increase the RF LEVEL by adjusting the attenuator and Variable controls
until the receiver just unsquelches.
a. On the display, read minimum squelch sensitivity as uV or dBm. This is the threshold squelch sensitivity of the
receiver.
b. Determine the tight squelch sensitivity of the receiver by repeating steps 4 and 5 with the receiver's squelch control
set to maximum tightness.
6. Enable the receiver's PL/DPL squelch circuit. Fully open the carrier squelch control. Increase the RF LEVEL from
minimum, as in step 5, until the receiver's squelch just opens. On the display, read the coded squelch sensitivity in uV
or dBm.
AUDIO POWER OUTPUT TEST
1.
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2.
3.
4.
5.
6.
7.
Set DISPLAY to Gen/Mon Mtr and FUNCTION switch to Generate FM. Enter the RF frequency and PL code.
Adjust attenuator and Variable controls to 1000 uV (-47 dBm). Adjust the I KHz Level control to 60010 of the rated
deviation on the DEV KHz scale. Push the Variable control in to select the RF In/Out connector.
Change DISPLAY to DVM/Dist and use the keypad to select DVM AC function.
Connect a suitable resistive load, that can dissipate the receiver's rated audio output, in place of the speaker. (If the re-
ceiver uses a "floating" or "bridge" output amplifier, connect a I: 1 isolation transformer across the load resistor.)
Connect a scope probe to the Analyzer's Vert/Sinad/Dist input connector and clip the probe across the load resistor
or to the isolation transformer.
Connect the RF In/Out to the receiver's antenna port. Adjust the receiver's volume control for the highest voltage
reading on the DVM AC scale which does not have clipping or other distortion in excess of radio specs.
Calculate the audio power output by the following formula:
Power Out (Watts)
=
(AC Voltsp
Load Resistance (Ohms)
8. If the receiver does not produce rated audio power output, use the Analyzer's OSCILLOSCOPE and a scope probe to
trace through the audio stages and locate the problem.
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