Analog Multiplexing with ADC: A Viable Solution?

[dyordyen]

Is it possible? Feasible?

 

[mgb_phys]

So a bunch of separate ADCs, some network hardware and a bunch of DACs and output amps?
Any reason to do this rather than just an analogue MUX?

 

[berkeman]

Is it possible? Feasible?

The function of an Analog-to-Digital converter (ADC) is nothing like an analog MUX function. What are you trying to do?

 

[chroot]

Using only ADCs? No, it's not possible.

- Warren

 

[dyordyen]

Oh wait, I'm sorry... I meant, multiplexing multiple analog signals then feeding it to an ADC...

 

[berkeman]

Oh wait, I'm sorry... I meant, multiplexing multiple analog signals then feeding it to an ADC...

Yes, that's done all the time. You use the MUX as the sample part of your sample and hold circuit, with the hold cap between the MUX and the ADC input. The sample time depends on the impedance of the MUX switches.

 

[rbj]

Oh wait, I'm sorry... I meant, multiplexing multiple analog signals then feeding it to an ADC...

Yes, that's done all the time. You use the MUX as the sample part of your sample and hold circuit, with the hold cap between the MUX and the ADC input. The sample time depends on the impedance of the MUX switches.

but don't do that with a sigma-delta ADC, unless the MUX switching rate is far, far slower than the clock for the sigma-delta ADC.

 

[dyordyen]

Thanks guys :)