感謝貓大不厭其煩的教導,讓小弟有比較正確的方向進行探索。
說真的,隔行如隔山,面對知識的浩瀚也只能點滴吸收慢慢前進了。
就小弟目前的survey,很多資料其實還無法融會貫通,大都一知半解,確認讓大大見笑了。
不過,在搜尋的過程中,我發現已經有針對性的product推出,例如:
Isolator:
Full galvanic isolator between SBC/DAC.
Unit will work on both master and slave DACs. We have isolated the i2c, gpios.
i2s Reclocker:
First, it has a very low jitter NDK crystal feed by LDOs in series for ultra quiet power supply. Second, the FPGA will read the incoming stream, will buffer the DATA 0.7s while discarding the incoming clocks. Using the NDKs it will reclock the buffered data OUTSIDE the fpga (since fpgas introduce about 200ps of jitter) and provide a MCLK/BCLK that is direct from crystal, providing a jitter-free (almost) to your DAC.
Meanwhile, it will clock the file using the correct crystal (there are 2), fixing the problems outlined in the beginning.
It will not work if your DAC is a master. Dac has to be slave.
看起來,已經有廠商開發相關的產品來提升樹莓派DAC的音樂表現,作爲相對低廉的投資其實不失一試就是了。