WM8991 datasheet(23/174 Pages) WOLFSON

23 / 174 page

Pre-Production

WM8991

PP, May 2008, Rev 3.1

TERMINOLOGY

Signal-to-Noise Ratio (dB) – SNR is a measure of the difference in level between the maximum theoretical full scale

output signal and the output with no input signal applied.

Total Harmonic Distortion (dB) – THD is the level of the rms value of the sum of harmonic distortion products relative

to the amplitude of the measured output signal.

Total Harmonic Distortion plus Noise (dB) – THD+N is the level of the rms value of the sum of harmonic distortion

products plus noise in the specified bandwidth relative to the amplitude of the measured output signal.

Crosstalk (L/R) (dB) – left-to-right and right-to-left channel crosstalk is the measured signal level in the idle channel at

the test signal frequency relative to the signal level at the output of the active channel. The active channel is

configured and supplied with an appropriate input signal to drive a full scale output, with signal measured at the

output of the associated idle channel. For example, measured signal level on the output of the idle right channel

(RIN2 to ADCR) with a full scale signal level at the output of the active left channel (LIN1 to ADCL).

Multi-Path Channel Separation (dB) – is the measured signal level in the idle path at the test signal frequency relative

to the signal level at the output of the active path. The active path is configured and supplied with an appropriate input

signal to drive a full scale output, with signal measured at the output of the specified idle path.

All performance measurements carried out with 20kHz low pass filter, and where noted an A-weighted filter. Failure to

use such a filter will result in higher THD and lower SNR readings than are found in the Electrical Characteristics. The

low pass filter removes out of band noise; although it is not audible it may affect dynamic specification values.

Mute Attenuation – This is a measure of the difference in level between the full scale output signal and the output with

mute applied.

WM8991 Datasheet(PDF) 23 Page - Wolfson Microelectronics plc