How to implement synchronous clocking

[regal]

With all the NOS TDA1543 designs, how would you modify them to do synchronous clocking with the DAC the master and the transport the slave.

[Alexandre]

Hi. This isn´t a simple task.

You could start by taking a look at the dddac schematic, half of what you need is there.

To implement the other half (transport sync´ing), my suggestion is to use a spdif transmitter ic like CS8406 at the dac. Use one of the master modes of the DIT, so you only need to input 11.2896 or 5.6448 to transmit, and tie the sdata input to ground. You will be transmitting spdif with your clock.

The advantage of this method is that you can sync both PC soundcards and CDPs. (You can place a CS841x DIR at the CDP to recover a suitable mck from your transmitted spdif. The CS8416 DIR can recover either 11.2896 or 16.9344.)

A good idea is to use toslink here, since interface jitter won´t matter as much.

[Ulas]

Originally posted by regal
With all the NOS TDA1543 designs, how would you modify them to do synchronous clocking with the DAC the master and the transport the slave.

Choose an oscillator frequency that is a multiple of both the bit rate of the DAC and the clock frequency of the CDP. Divide the oscillator with a synchronous counter to get FSYNC, SCLK, WCLK, and BCLK for the DAC and the clock for the CDP. For NOS, FSYNC = WCLK and SCLK = BCLK, but be careful to maintain the proper the phase relationships. Use a differential transceiver in the DAC to send and one in the CDP, in place of the OEM oscillator, to receive the synchronizing clock. Connect with UTP. With full- duplex transceivers you can also transfer S/PDIF via UTP making a single cable connection between the CDP and DAC.