Re: [LAD] Drift compensation document

From: Fred Gleason <fredg@email-addr-hidden>
Date: Sat Sep 02 2017 - 18:54:15 EEST

On Sep 2, 2017, at 06:26, benravin <ben.alex@email-addr-hidden> wrote:

> If audio sample rate of a radio receiver has to be matched with respect to
> transmitter radio station audio sample rate, then some timing information
> has to be derived. But, in case of broadcast digital radio receivers, there
> is no information about the time stamps in the received data as metadata
> information. How to timestamp and do the drift compensation in this
> scenario?

One approach that I’ve used with good success here is to run the decoded PCM through a FIFO buffer between the SRC and the play-out stages and then use the size of that FIFO (which will change dynamically in response to things like network congestion) to feed a PLL that drives the converter ratio for the SRC stage. The trade-off for this approach of course is increased latency. If true low-latency operation is required, then some sort of clocking (ala AES67) will be required.

Cheers!

|----------------------------------------------------------------------|
| Frederick F. Gleason, Jr. | Chief Developer |
| | Paravel Systems |
|----------------------------------------------------------------------|
| A room without books is like a body without a soul. |
| -- Cicero |
|----------------------------------------------------------------------|

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Received on Sat Sep 2 20:15:01 2017

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