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3channel ADC 24 bits for AM carrier frequency 100kHz

javier gracia
Prodigy 20 points
Other Parts Discussed in Thread: ADS1672

Hello,

I need to sample an amplitude modulated signal with a carrier frequency of 100kHz and band with of 200Hz with a resolution of 24bits. I need 3 channes with this characteristics, and would like to have it in one chip.

I wonder if :
A : is there any of your microprocesors or DSPs with at least 3 ADC 24bit and sampling frequency > 200kHz ?
B : AN other option is a so call Bandpass sigma-delta converter (from analog documentation MT-023 page 9  [1]) is there any system that includes this and/or allows to implement this?
C: is there any other possible solution that I'm missing ??


Thanks.


[1]
W. Kester, ADC Architectures IV: Sigma-Delta ADC Advanced Concepts and Applications. .
  • 0
    Guru 27285 points

    javier gracia said:
    I need to sample an amplitude modulated signal with a carrier frequency of 100kHz and band with of 200Hz with a resolution of 24bits. I need 3 channes with this characteristics, and would like to have it in one chip.

     Why sample at a so high resolution and why unusual 3 channel?

     At that speed grade this device can suit your need http://www.ti.com/product/ads1672

    javier gracia said:
    C: is there any other possible solution that I'm missing ??

     All details required to be of some help selecting processor/DSP and ADC too.

     

  • 0 in reply to Roberto Romano
    Prodigy 20 points

    thanks for ur answer Roberto

    I need to sample a 100kHz carrier frequency that contain 200Hz changes in amplitude (as in amplitude modulations).

    So far I used a 16bit ADC and undersample the signal at 10kHz. However, i need to increase the resolution.

    I've seen all 24 bit ADC are based on sigma delta thechniques. I believe I cannot do undersampling with this method, this i why I believe i need to do Niqust sampling (2x100kHz ->  fs>200kHz).

    I already saw the ads1672

    However, it has only one channel. I could use 3 ( or more, 3 is just an example) individual ads1672, but that implies to develope a PBC my self.

    I would like to know is there is some test board that allows me to test a multichannel 24bit ADC for my purpose, before start building anything.

    Thanks

  • 0 in reply to javier gracia
    Guru 27285 points

    javier gracia said:

    I need to sample a 100kHz carrier frequency that contain 200Hz changes in amplitude (as in amplitude modulations).

    So far I used a 16bit ADC and undersample the signal at 10kHz. However, i need to increase the resolution.

    I've seen all 24 bit ADC are based on sigma delta thechniques. I believe I cannot do undersampling with this method, this i why I believe i need to do Niqust sampling (2x100kHz ->  fs>200kHz).

     Hi, in your post there are some part striding together...

     What the content of this modulation to be extracted from to require a so HIGH resolution of 24 bit and specialized PCB design to reduce noise and rf path to get clean sample??

     This is a non simple task! So why 3 channel and why 24 bit? It need phase extraction of carrier?

     Again if you sample at theoretical Shannon/Nyquist frequency your sampled wave can suffer of undersampling too, to use 24BIT different techniques need to be applied so a 4 bit sampling extract a similar content of your 24 bit...

     What is your goal? How much power is required by DSP?

    javier gracia said:

    I would like to know is there is some test board that allows me to test a multichannel 24bit ADC for my purpose, before start building anything.

     You can use 3 demo board from that ADC but before check if your goal is achievable too.