Freedom R8100 SERIES, Operator'S Manual

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Figure 5.2.1-1 Setup for FM Receiver testing
Place the R8100 in Generator mode by pressing the Generate front panel hard key. Press the RF Zone
soft key and set the Generator Frequency to match that of the radio under test and the Modulation Type
to FM. Set the Bandwidth just wide enough to cover the channel spacing allocated to the radio under
test.
For initial setup set the RF output level to at least 30 dB above the receiver’s sensitivity threshold. A
starting level of -80 dBm is recommended. Navigate to the Audio Zone and set the Fixed 1 kHz Mode
to Continuous. Set the Fixed 1 kHz Level to 60% of the system deviation for the receiver. For
narrowband 2 way radios a typical setting is 3 kHz. Page through the submenu and set the High Pass
Filter to 300 Hz and the Low Pass Filter to 3 kHz.
Navigate to the Meter Zone and select the AC Volts meter. Adjust the radio for rated power output by
calculating the voltage needed across the load resistor/speaker in use. Adjust the radio volume until the
meter reads the calculated voltage.
Navigate to the Display Zone and select the Oscilloscope display. Adjust the vertical and horizontal
settings and observe the recovered audio sine wave from the receiver.
4.2.2 Receiver Distortion Measurement
Navigate to the Meter Zone and select the External Distortion meter. Read the displayed distortion in
percent and compare the radio’s service manual specification to determine if any repairs or adjustments
are needed.