AM Receivers
158
On the Signal Generator:
17.Set RF Power to ON.
18.Set Output Level to 31.6 mV.
19.Set Output Frequency to lowest frequency being checked (typically
<1 MHz).
20.Set Modulation to internal AM.
21.Set Modulation rate to 400 Hz.
22.Set Modulation Depth to 30%.
23.Tune the Signal Generator in 1 kHz steps from the minimum to maximum
frequency and note frequencies where SINAD decreases below 10 dB.
❒If necessary, increase tuning resolution on the Signal Generator an d ad-
just as required to locate frequency causing maximum degradation of
the SINAD reading.
24.For each frequency where SINAD is degraded, reduce the Signal Generator
RF output level until SINAD of 10 dB is obtained.
• Record the Signal Generator frequency and level.
25.Repeat step 23.and step 24. until all spurious responses are measured.
Calculate the Spurious Response:
26.The minimum result is the calculated spurious response attenuation.
calculated spurious response attenuation
Each Spurious response level recorded in step 25
Amplitude level recorded step 17