EFFBIT

Purpose:

Calculate the number of effective bits possible at a given frequency for a quantizing device.

Syntax:

EFFBIT(series, freq, fs)

series	-	A series or table. The input sinusoid.
freq	-	A real, the known frequency of the input sinusoid. Defaults to -1, estimate the frequency.
fs	-	Optional. A real, the full scale input amplitude of the device being tested. Defaults to abs(max(series) - min(series)).

Returns:

A scalar constant.

Example:

W1: gsin(1000,1/1000,4)

W2: quantize(W1, 8)

effbit(w2, 4)

returns 2.81, indicating the number of effective bits at a frequency of 4 Hertz is slightly less than 3, the ideal number of bits for 8 levels of quantization.

Remarks:

This routine uses the SINFIT3 to fit a sine wave to the input data with a known or unknown frequency. The input is assumed to be a sinusoid.

The number of effective bits is calculated as:

$image\effbit01.gif$

where F_s is the full scale input fs and e_rms is the RMS error between the input waveform and the fitted sinewave.

References:

IEEE Std 1057-1994