Simple I2S multiplexer

NicMac

Member
2009-02-26 8:34 pm
Hi All,
I would like to make a dedicated digital "multi source" receiver taking a variety of digital media (SD-cards, USB, CD's, etc.) all outputting I2S (up to 192 KHz/24 bit). The I2S signal will be transmitted to my DAC by cable. To make this work I would need a 3-4:1 I2S multiplexing circuit/IC.
I have looked a bit around but I cannot seem to find anything that fits the bill (excluding arrays of relays and rotary switches).
Any ideas?
Thanks
 

wakibaki

Banned
2008-01-08 11:51 pm
CMOS multiplexer:

http://focus.ti.com/lit/ds/symlink/cd4512b.pdf

This has 10 lines, you'd need 3 of them and some way of selecting the channels. You could do that with switches, there are 3 inputs, you'd only need 2 for 4 lines, you'd need to set up the switches with a digital number 0-3 for 4 switches, or you can have 4 individual switches and use an encoder, which you can build with a few gates:

Priority encoder - Wikipedia, the free encyclopedia

So that only one line is active, a rotary switch to select the active input would be preferable, or you could use a PIC micro with a single pushbutton (momentary) switch to cycle between the inputs, in which case you could do without the encoder.

There are many, many logic multiplexer chips available. Probably 74HC or 74HCT are the most robust types.

The best approach really depends on exactly what you want, obviously if you use chips, you'll need a power supply and you'll need to assemble them on a board, although Veroboard will be adequate.

w
 

wakibaki

Banned
2008-01-08 11:51 pm
4-1, 3 line multiplexer

As shown, J1 is selected, as the switch is rotated anticlockwise, J2, J3 & J4.

multiplexer2.jpg

w