AM Distortion

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.

Required Test Equipment

This test supports two equipment setups using either a spectrum analyzer or a measuring receiver. The spectrum analyzer is the preferred solution.

  1. The preferred solution uses a spectrum analyzer with Analog Demodulation Measurement Application to demodulate the signal and measure the deviation.

    Test Equipment

    Critical Specifications for This Test

    Recommended Models

    Alternate Models

    Spectrum Analyzer

    AM Demodulated Distortion (< 50% AM) ≤ 0.3%

    N9030B Opt 5xx1, N9063C-1FP Analog Demodulation Measurement Application

    N9030A Opt 5xx1 and N9063A-2FP or 2TP Analog Demodulation Measurement Application2

    E444xA3 Opt 233

    1. Select any option of PXA spectrum analyzer (503, 508, 513, 526, 543, 544, 550) that has a maximum frequency greater than or equal to the maximum frequency of the unit under test.

    2. To use the PXA N9030A with N9063A analog demodulation measurement application functionality above 3.5 GHz, the N9030A must be upgraded with either Option MTU or TES. For more information, see the main Required Equipment table.

    3. Select any model of PSA spectrum analyzer (E4440A, E4443A, E4445A, E4446A, E4447A, E4448A) that has a maximum frequency greater than or equal to the maximum frequency of the unit under test.

  2. The alternate solution uses an 8902A measuring receiver to demodulate the signal and measure the deviation.

    Test Equipment

    Critical Specs for This Test

    Recommended Models

    Alternate Models

    Measuring Receiver

    AM Demodulated Distortion (< 50% AM) ≤ 0.3%

    8902A

     

    Audio Analyzer1

    Distortion (20 Hz to 20 kHz) < –80 dB*

    * The distortion accuracy of the 8903B is worse than the specified AM distortion of the UUT. Therefore, the indicated distortion must be greater than the specification by at least the amount of the 8903B distortion measurement accuracy.

    8903B

     

    Mixer1

    RF/LO Freq Range: 800 to 3000 MHz

    IF Frequency Range: 10 to 1000 MHz

    RF 1 dB compression: +1 dBm

    M/A-COM MDC-164

    0955-2225

    Local Oscillator1

    Frequency Range: 800 to 2500 MHz

    Amplitude : +16 dBm

    E8267D Opt UNR or UNX or UNY

    E4428C Opt 503 or 506
    E4438C Opt 502, 503, 504, or 506, and UNJ

    E8241A Opt UNJ
    E8244A Opt UNJ
    E8251A Opt UNJ
    E8254A Opt UNJ

    E8247C Opt UNR
    E8257C Opt UNR
    E8267C Opt UNR

    E8257D Opt UNR or UNX or UNY

    E8663B
    E8663D Opt 503 or 509

    N5181B/82B Opt 503 or 506
    N5171B/72B Opt 503 or 506
    N5182A Opt 1EA

    1. Not used for ESGs with a frequency range of < 2 GHz.

Connections and Setup Procedures

  • All test equipment requires a 30 minute warmup period to ensure accurate performance.
  • In the following test setup, cables are designated as solid lines and direct connections are designated as dashed lines.
  1. Connect all test equipment as shown.
  2. Connect GPIB cables to all GPIB-controlled test equipment.
  3. While performing this test, follow all instructions on the controller display.

 

Spectrum Analyzer Test Setup

 

 

Measuring Receiver Test Setup

 

Calibration Setup


 

 

AM Distortion CW Frequency < 1300 MHz Test Setup

 


 

 

AM Distortion CW Frequency > 1300 MHz Test Setup

 

In Case of Difficulty

If this performance test fails, perform the following steps in order:

  1. Check the equipment setup (see above). If the setup is incorrect, make the necessary corrections and rerun the performance test.

  2. If this test fails with the equipment set up properly, refer to the troubleshooting section of the signal generator's service guide. If you do not have a printed copy of the service guide (Option OBW), one is available either on the CD-ROM that came with your signal generator shipment or on the Keysight Website.

  3. If you cannot correct the problem using the troubleshooting procedures in the Service Guide, obtain service from Keysight Technologies. Refer to Contacting Keysight Technologies.