AM distortion is defined as the square root of the ratio of the power contained in the harmonics of the demodulated AM waveform to the power of the fundamental component of the demodulated waveform.
This is essentially a total harmonic distortion (THD) measurement, and is made directly by the 8903B audio analyzer. The THD indicated by the 8903B includes the distortion added by the measuring receiver.
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Instrument |
Critical Specifications for This Test |
Recommended Model |
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Measuring Receiver |
AM Demodulated Distortion (<50% AM) ≤ 0.3% |
8902A |
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Audio Analyzer |
Distortion (20 Hz to 20 kHz) < -80 dBa |
8903B |
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Mixer Not used for ESGs with frequency range <2 GHz |
RF/LO Freq. Range: 1 to 2800 MHz IF Frequency Range: 1.5 MHz RF 1 dB compression: +8 dBm RF/LO Freq. Range: 500 to 9000 MHz IF Frequency Range: 50 MHz |
M/A-COM MDC-174 M/A-COM MDC-164 |
|
Local Oscillator Not used for ESGs with frequency range <2 GHz |
Frequency Range: 800 to 2500 MHz Amplitude: 16 dBm |
E8241A |
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aThe distortion accuracy of the 8903B is worse than the specified AM distortion of the DUT. Therefore, the indicated distortion must be greater than the specification by at least the amount of the 8903B distortion measurement accuracy. |
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Connections and Setup Procedures
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All test equipment requires a 30 minute warm-up period to ensure accurate
performance. |
Connect all test equipment as shown.
Connect GPIB cables to all GPIB-controlled test equipment.
While
performing this test, follow all instructions on the controller display.
Measuring Receiver Calibration Setup
AM Distortion CW Frequency <= 1300 MHz Test Setup
AM Distortion CW Frequency > 1300 MHz
