IMD Measurement with 19 kHz and 20 kHz Tones

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Created on 2010-11-25 01:50:00

Question:
How do I set up an IMD test signal with 19 kHz and 20 kHz tones?

Answer:
An IMD measurement with 19 kHz and 20 kHz tones is useful for evaluating distortion at the top end of the audiblefrequency range, which is not revealed with lower frequency IMD tones or with traditional bandwidth-limited THD+Nmeasurements. To set up the various AP analyzers to do this measurement, follow these steps:

APx:

  1. Add the IMD measurement to the navigator.
  2. Set IMD Type to DFD.
  3. Set Waveform to Sine.
  4. Set Mean Frequency to 19.5 kHz.
  5. Set Diff Frequency to 1 kHz.

AP2700, APWin:

  1. In the Analog Generator panel, set Wfm: (waveform) to IMD.
  2. Set the waveform sub-type to CCIF/DFD.
  3. Set Center Freq to 19.5 kHz.
  4. Set IM-Freq to 1 kHz.

The ATS-2, ATS-1, and Portable One can not do IMD CCIF/DFD measurements.

Applies to: APx, AP2700, APWin, ATS-2, ATS-1, Portable One.