Summary
Slew-induced distortion (SID or slew-rate induced distortion) is caused when an amplifier or transducer is required to change output (or displacement), i.e. slew rate, faster than it is able to do so without error.[1] At such times any other signals may suffer considerable gain distortion, leading to intermodulation distortion.[2] Transient intermodulation distortion may involve some degree of SID and/or distortion due to peak compression.
These are effects that tend to occur only during parts of a waveform fed through audio amplifiers, that may give rise to audible degradation of the sound quality in music, even when fixed-frequency harmonic distortion tests show low amounts of distortion for a simple sinewave test signal.[dubious ][citation needed]
TIM (Transient Intermodulation Distortion) was first discovered by Matti Otala in the 1960s due to accidentally wiring an amplifier incorrectly.[3]
References edit
- ^ [1] An Overview of SID and TIM by Walter G. Jung, Mark L. Stephens, and Craig C. Todd in Audio, June 1979;
- ^ http://www.aes.org/par/i/#IM AES Pro Audio Reference for Intermodulation Distortion
- ^ Curl, John (May 2006). "Condemnation without Examination is Prejudice" (PDF). Q Audio. Sacramento, California. p. 9. Archived from the original (PDF) on 2013-11-10.
First, Matti Otala found, back in the 1960s, by accidentally miswiring a power amp, that negative feedback was a problem with the subjective performance of audio circuits. Otala found that when both the open loop bandwidth increased and the feedback was reduced, the amp sounded better.