Measurement of Polarity in Band-Limited Systems

Keele J,DB(. Measurement of Polarity in Band-Limited Systems. In: AES Convention 91. Audio Engineering Society; 1991. Paper 3168. Available from: https://aes.org/publications/elibrary-page/?id=5548

@inproceedings{Keele1991_5548,
  author = {Keele, Jr., D. B. (Don)},
  title = {{Measurement of Polarity in Band-Limited Systems}},
  booktitle = {AES Convention 91},
  note = {Paper 3168},
  year = {1991},
  month = oct,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=5548}
}

TY  - CPAPER
TI  - Measurement of Polarity in Band-Limited Systems
AU  - Keele, Jr., D. B. (Don)
T2  - AES Convention 91
M1  - Paper 3168
PY  - 1991
DA  - 1991/10/06
UR  - https://aes.org/publications/elibrary-page/?id=5548
PB  - Audio Engineering Society
LA  - en
AB  - Polarity is usually measured by energizing the system under test with a wide-band asymmetrical test stimulus, such as a raised cosine pulse, and then observing the system's output on an oscillioscope. For a well-behaved flat-response minimum-phase system, such as an electronic device, the polarity determination is straightforward. However, for a general band-limited non-minimum-phase system with non-flat frequency response, such as a loudspeaker, the policy assessment can be quite difficult due to waveform distortion. A measurement method is presented that uses a narrow-band asymmetrical Hann-windowed tone burst, along with synchronous detection, to evaluate polarity at many points across a desired bandwidth. For a general system evaluated with tone bursts over a narrow frequency range, polarity is not just a simple two-valued function, but a continuum of values over the range of +/- 180 degrees, that varies with frequency. A preliminary theory is presented that allows prediction of the tone-burst phase, and hence time-constrained narrow-band polarity (herein called polarity phase), from the systems's conventional steady-state sinusoidal phase and group-delay responses.
ER  -