A Fully In-Band Multitone Test for Transient Intermodulation Distortion
Journal of the Audio Engineering Society
This paper describes a Multitone Intermodulation (MIM) distortion test that employs three tones at 9.0 kHz, 10.05 kHz and 20 kHz in equal proportions. The advantage of this high frequency IM test is that it produces both even-order and odd-order (triple beat) distortion products in the vicinity of 1 kHz. This makes it easy to separate the test signal from the distortion products, making it possible to build very sensitive, yet affordable, instrumentation. The paper describes MIM source and analyzer instrumentation and shows how MIM distortion measurements correlate with other high-frequency distortion measurements like 20 kHz THD and the DIM-30 test for Transient Intermodulation Distortion (TIM).