I'm working on a project which uses an Si4731 broadcast radio receiver IC (Si47xx family) and which calls for left & right demodulated audio level meters based on a source FM broadcast signal. I expect this to be available via I2C from the IC. However, I've read through the manufacturer's programming guide (linked above) like five times now and I'm still not sure.

The closest thing that I've found to this in the above-linked guide is the TX_ASQ_STATUS (Audio Signal Quality) property, but I don't see exactly how it would apply here. I'm already reading the FM_RSQ_STATUS (Radio Signal Quality) property and using that to get the Radio Signal Strength (for RSSI), Signal-to-Noise Ratio (SNR), and FM "Pilot" indicator via I2C. Perhaps it's in there somewhere and I'm overlooking it?

Can someone with more experience with radio receiver ICs please help me understand this better?


I do not believe it does, but you can just process the digital audio stream to derive whatever style of metering you desire.

Audio metering is a can of worms, there are literally dozens of different standards worldwide, VU, PPM (But which scale?), DPM (But what dynamics), Loudness (There are at least three), nobody is going to bother with that in a simple radio chip, far better to leave that to the customers processor if they really want it.

Bring the I2S or whatever format makes sense into your micro and do the sums on it.

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