PCM1803: Group delay time

Hailey Chen

Part Number: PCM1803

Hi, team:

Nice to meet you!

I noticed in PCM1803 datasheet their describe tGD (Group delay time) is 17.4/fs ，could you help explain how to understand tGD , does it mean delay time of input and output signal?

If I set 96Khz，and have an signal high voltage only 100us, whether PCM1803 could capture and convert? Whether it will be effected by the tGD？

Hope to get your reply，thanks!

over 2 years ago

0 Jeff McPherson over 2 years ago

TI__Mastermind 46445 points

Hi Hailey,

Group Delay is not the delay between input and output. The definition is the negative time derivative of phase delay. It describes how envelopes of signals get delayed through a system. This website describes it the best for me: https://circuitcellar.com/research-design-hub/group-delay-basics-more-filter-fun/

The group delay in the datasheet is the worst group delay measured in the audio pass band (20Hz - 20kHz).

A 96kHz sample rate gives a maximum signal frequency of 48kHz => 20.83 us period, so a 100us signal is fine and it will be effected by the group delay.

Best regards,
Jeff McPherson

Audio

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PCM1803: Group delay time