Pre-Production
WM8850
TERMINOLOGY
1. Signal-to-Noise Ratio (dB) – SNR is a measure of the difference in level between the full scale output signal and the
output with no input signal applied.
2. 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 applied input signal.
3. 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 applied input signal.
4. 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 with a full
scale signal level at the output of the active left channel.
5. 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.
6. 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.
7. Mute Attenuation – This is a measure of the difference in level between the full scale output signal and the output with
mute applied.
8. Channel Level Matching (dB) – the difference in output level between channels in a stereo pair.
9. Channel Phase Deviation (Degrees) – the difference in phase between channels in a stereo pair.
10. Idle Channel Noise (dBV) – absolute rms measurement of the noise floor over the 20Hz to 20kHz band.
PP, April 2011, Rev 3.2
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
