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, N9063EM0E Analog Demodulation Measurement Application	N9030A Opt 5xx1 and N9063EM0E Analog Demodulation Measurement Application2 E444xA3 Opt 233

   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. To use the PXA N9030A with N9063EM0E 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. 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	0955-2225	M/A-COM MDC-164
   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

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.