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Journal Article

Phase Intermodulation Distortion Instrumentation and Measurements

Authors: Cordell, Robert R.

Journal of the Audio Engineering Society · Volume 31 · Issue 3 · pp. 114–124 · March 1983

Abstract

Phase intermodulation (PIM) distortion in audio amplifiers, in particular that which may arise from the use of negative feedback, is considered. PIM theory is discusseed and the linking of PIM to amplitude intermodulation (AIM, or SMPTE IM) distortion is illustrated. It is noted that amplifiers without negative feedback are also likely to produce PIM. Coherent SMPTE IM instrumentation capable of resolving less than 2 ns of equivalent time dispersion and measurement results from several different real amplifiers are presented. The results show that PIM is not a problem in contemporary amplifiers and suggest that negative feedback reduces total PIM in most cases.

Details

Publication
Journal of the Audio Engineering Society
Volume
31
Issue
3
Pages
114–124
Publication date
March 6, 1983
Type
Journal Article