Author Topic: AES17 - THD+N vs Frequency  (Read 250 times)

David Samborsky

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AES17 - THD+N vs Frequency
« on: October 03, 2020, 01:13:46 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.
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David Samborsky

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Re: AES17 - THD+N vs Frequency (-1dBFS)
« Reply #1 on: October 04, 2020, 02:35:04 AM »
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David Samborsky

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Re: AES17 - THD+N vs Frequency (-20dBFS)
« Reply #2 on: October 04, 2020, 02:35:47 AM »
The home of the Ultimate-Preamplifier and Ultimate-Amplifier ! https://www.analog-precision.com/