WM8940(2011) データシートの表示（PDF） - Wolfson Microelectronics plc
部品番号
コンポーネント説明
メーカー
WM8940 Datasheet PDF : 91 Pages
| |||
WM8940
Production Data
TERMINOLOGY
1. Full-scale input and output levels scale in relation to AVDD or SPKVDD depending upon the input or output used. For
example, when AVDD = 3.3V, 0dBFS = 1Vrms (0dBV). When AVDD < 3.3V the absolute level of 0dBFS will decrease
with a linear relationship to AVDD.
2. Input level to RIP and LIP in differential configurations is limited to a maximum of -3dB or performance will be reduced.
3. Signal-to-noise ratio (dB) – SNR is the difference in level between a reference full scale output signal and the device
output with no signal applied. This ratio is also called idle channel noise. (No Auto-zero or Automute function is
employed in achieving these results).
4. Total Harmonic Distortion (dB) – THD is the difference in level between a reference output signal and the first seven
harmonics of that signal. The reference output signal need not be at full scale amplitude; THD is typically measured
using an output power of 20mW into a 16ohm load, corresponding to a reference signal level of -5dB. However the
stated test conditions include input signal level, signal gain settings, output load characteristics and power supply
voltages To calculate the ratio, the fundamental frequency of the output signal is notched out and an RMS value of the
next seven harmonics is calculated.
5. Total Harmonic Distortion plus Noise (dB) – THD+N is the difference in level between a reference output signal and
the sum of the harmonics, wide-band noise and interference on the output signal. To calculate the ratio, the
fundamental frequency of the output signal is notched out and an RMS value of the total harmonics, wide-band noise
and interference is calculated.
6. Channel Separation (dB) – Also known as Cross-Talk. This is a measure of the amount one channel is isolated from
the other. Normally measured by sending a full scale signal down
w
PD, Rev 4.3, November 2011
10
Share Link: 