Author Topic: AES17 - THD+N vs Frequency  (Read 1268 times)

Tranquility Bass

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AES17 - THD+N vs Frequency
« on: October 03, 2020, 11:13:46 PM »
Applies to: EUTs with analogue or digital inputs and analogue or digital outputs.

Aim: To measure the THD+N of the EUT against frequency.

Method
A –1dBFS sinusoidal stimulus is applied to the EUT, successively at each octave frequency between
20Hz and half the upper band-edge frequency. The output of the EUT is passed through a standard
notch filter at the frequency of the stimulus, and also through a low-pass filter at the upper band-edge
frequency (or at 20kHz, whichever is the lower). The RMS amplitude of the residual is measured for
each stimulus frequency.

The results are presented graphically, with THD+N (in % relative to the amplitude of the stimulus)
being plotted for each channel against stimulus frequency.

The test is then repeated with a stimulus amplitude of –20dBFS, the results being overlaid on the
original graph.
"The only thing necessary for the triumph of evil is for good men to do nothing" -John Stuart Mill,

Tranquility Bass

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Re: AES17 - THD+N vs Frequency (-1dBFS)
« Reply #1 on: October 04, 2020, 12:35:04 PM »
"The only thing necessary for the triumph of evil is for good men to do nothing" -John Stuart Mill,

Tranquility Bass

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Re: AES17 - THD+N vs Frequency (-20dBFS)
« Reply #2 on: October 04, 2020, 12:35:47 PM »
"The only thing necessary for the triumph of evil is for good men to do nothing" -John Stuart Mill,

 

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