Re: Sigma-Delta A/D


Ray Andraka skrev:

> Marco wrote:
>
> >
> >I understand... so a way to do it could be buying a analog devices ad7400
> >(isolated sigma delta modulator (1 bit out)) and building the digital filter
> >into the fpga to obtain 16 bit output data.
> >
> >What do you think about it?
> >
> >
> >
> >
> That works just fine, and it can be done in a small FPGA with careful
> design. I did an 8 channel one in an XC2S15 using external DS modulators.
>

I wonder what the intended application is for the ad7400, why the
isolation,
why only the DS modulator wouldn't most people get a whole ADC when
they have
to add a chip anyway?

Why did you use it instead of a full ADC, Ray?

-Lasse

.

Relevant Pages

  • Re: Digital wireless systems
    ... gathered so far is that a digital frequncy modulator can be made using ... a FPGA and the demodulator can also be made using FPGA. ... Step 4,5,6 could be adapted for direct conversion, which ...
    (sci.electronics.design)
  • Re: Lookup Table Vs. FIR For Modulator Pulse Shaping
    ... My first thought was to use an FIR ... A lut is a very common way to implement a modulator. ... Even in an FPGA, if the symbol rate is fixed, this is often the most ...
    (comp.dsp)
  • Re: Digital wireless systems
    ... I am looking for a digital design or technique that I can use to ... gathered so far is that a digital frequncy modulator can be made using ... a FPGA and the demodulator can also be made using FPGA. ... RF PCB layouts are very tricky. ...
    (sci.electronics.design)
  • Re: selection of Fpga
    ... i'm new to using Fpga.My project is design of modulator using Fpga based ... on Dsp technology.My data rate is 12Mb and Intermeadiate freq is 140 ... Scratch out your modulator design as a block diagram, then look at the arithmetical operations you're going to be doing and the sampling rate you feel you need to achieve. ...
    (comp.dsp)
  • Re: Lookup Table Vs. FIR For Modulator Pulse Shaping
    ... modulator in hardware (FPGA or CPLD). ... A lut is a very common way to implement a modulator. ... Even in an FPGA, if the symbol rate is fixed, this is often the most efficient way to do it. ...
    (comp.dsp)