High Sampling Rate of Analog or Digital Conversion to PWM

[amartin32]

So I have been looking for the easiest way of going about sending analog signals via an fiber optic cable and one of the ways is to go from analog signal to digital to PWM. I need to have a sampling >= 10 MHz and >= 12bits of precision (Cost is also an issue/ >$1000).

So I found this Fiber Link Evaluation board: Part number = 516-2318-ND (on Digikey.com)

And this ADC Evaluation board: Part number = EVAL-AD7626EDZ (on Digikey.com)

However there does not seem to be an easy and simple way of converting analog to PWM (thats why I am looking at the ADC) or to go from digital to PWM.

On the receiver side of the fiber link I think I can use Labview to convert from PWM to the analog signal. The only problem I am having is going from Analog to PWM at a high sample rate.

Any feedback and comments is greatly appreciated!

 

[dick_freebird]

There are easy / cheap PWM conversions, but accuracy is
not typically their reason for being; more usually they are
a part of a closed loop assembly and not error-significant.

I think a serial output ADC and serial input DAC would be
the most FO-link-friendly. If you have a multibit link (x4 is
common) you can send data and clock with lanes to spare.

 

[crutschow]

PWM is not generally appropriate for doing high speed, high accuracy analog to digital conversion. Better to use a standard serial output ADC.

 

[KlausST]

Hi,

crutschow is right.

I need to have a sampling >= 10 MHz and >= 12bits of precision

then you need a counter clock rate of 10MHz x 2^12 = 10MHz x 4096 = 40.96 GHz.
and if you need that precision then you need to transmit an receive it with a precision of 25ps.

Good luck.

Klaus

 

[amartin32]

Thank you for your feedback.

KlausST and Crutschow, I assume that a cost effective 40GHz counter clock is out of the question.

So I have also looked into transmitting the signal using a carrier frequency to use these transmitter and receiver:

Receiver: https://www.digikey.com/product-search/en?KeyWords=AFBR-2310Z&WT.z_header=search_go
Transmitter: https://www.digikey.com/product-search/en?KeyWords=AFBR-1310Z&WT.z_header=search_go

However I have not found an analog to RF modulator or demodulator evaluation board or circuit that can do this. Do you guys foresee any problems with this. I know that RF to Fiber is how cable and internet companies send their information but I can't find any modulators/demodulators for analog.

Thanks again for your help.