Trying to figure out the polarity of the emphasis / de-emphasis signals on these chips. Does anyone know?
The CS8415A receiver puts out a /EMPH signal, active low. The DF1704 inputs a DEM signal, active high. I'm confused on polarity. One is emph, the other de-emph, which technically are opposite? Can I connect pins directly or need inverter in between?
Thanks!
jh
The CS8415A receiver puts out a /EMPH signal, active low. The DF1704 inputs a DEM signal, active high. I'm confused on polarity. One is emph, the other de-emph, which technically are opposite? Can I connect pins directly or need inverter in between?
Thanks!
jh
You'll need to use an inverter.
Edit -- Geez, I just noticed that the question was posted by Jim Hagerman. I've got enough respect for you and your great website that I'll spend a bit more time to flesh out the answer!
The pre-emphasis can only be applied at the record end of the chain. The discrepancy in nomenclature occurs because the Crystal receiver is detecting the presence of pre-emphasis, while the Burr-Brown digital filter is applying de-emphasis.
Edit -- Geez, I just noticed that the question was posted by Jim Hagerman. I've got enough respect for you and your great website that I'll spend a bit more time to flesh out the answer!
The pre-emphasis can only be applied at the record end of the chain. The discrepancy in nomenclature occurs because the Crystal receiver is detecting the presence of pre-emphasis, while the Burr-Brown digital filter is applying de-emphasis.
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