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為何SDM ADC 第一級anti-alias filter cut off frequency 是20KHz??* @+ g# j. x/ j
通常audio digital output sample rate is 44.1/48/96/192KHz
% b& e" q( A$ f% j( g8 ibut the first anti-alias filter in analog SDM ADC input is 20KHz! x1 x. I2 m; p& @$ R. T
if your sample rate is 192KHz, its fs/2 is 96KHz, 20KHz~96KHz will be attenuated by anti-alias filter
l; a! a X% I, Ewhat is the difference with 48/96/192? the signal information is only under 20KHz.$ p" \2 f, v& @, O: [" d2 K- j6 F
who can tell me what is the difference in this condition?! I8 g/ J9 \: p
and is it really used 20KHz as the anti-alias of SDM ADC for audio? |
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