I2S interface?

[pooge]

What happened to this interface? Did it fall into oblivion just because of the demise of Audio Alchemy and Sonic Frontiers? Is it incapable of 24/96? Is it because the latest chips handle S/PDIF and wipe out the inherent jitter?

[dmfraser]

I2S is the standard internally in products and I use it extensively. However, because of the need to have lines carrying two or three different clock frequencies, it is inconvenient to use for external connections. For connecting between equipment, the S/PDIF or AES/EBU formats are used because these need only a single cable or fiber.

I use a DIR1703 from TI to convert from S/PDIF or AES/EBU back to I2S for internal feed to the DSP, etc.

I do all my work with 24 Bit/96KHz as my lowest quality signal and work up from there.

[Pitch254]

DMFRASER,

How do you interface the balanced aes3 to the dir 1703?

What I had in mind is receiver couple transformer, dc blocking cap, both floating outputs of the transformer to properly biased schmitt triggers.
Output of the both schmitt triggers to a voltage comparator, used for RS485 receiving. Output should be nicely squared fed into the 1703.

How do you do it?

[dmfraser]

Through a High Frequency coupling transformer through a DC blocking cap to the input of one section of a 74AC04. The 74AC04 was biased to about 40% of the supply voltage with two resistors. From the 74AC04 output I use a second section of the 74AC04 to square things up before going to the DIR1703.

I have also had good results using two of 74AHC1GU04 which is a 5 pin sevice with a single 74AHC type inverter in it. I have tried AC or DC coupling the signal to the second device but it seems to make little difference.