I found 
https://audiophilesoft.ru/articles/realtek_audio_setup/ALC887.pdf
In the pdf file, refer to pages 64, 67, 71, and 72. I don't understand it
well, but it doesn't say whether clock signals are emitted when there is no
audio signal.
On Fri, Aug 9, 2019 at 11:18 AM Chris Caudle <chris(a)chriscaudle.org> wrote:
  On Thu, August 8, 2019 6:39 pm, crocket wrote:
  If there is no audio data from SPDIF out, would
SPDIF out still send 
 clock
  signals? 
 Often that is the case, but you would have to consult the documentation
 for your particular audio interface to verify.
 --
 Chris Caudle
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