Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Sigma-delta DAC, FPGA platform

Dear All!

I am a PhD student at the Electroacoustics Division on Warsaw University of Technology. Currently I am working on sigma-delta DACs and sigma-delta modulators. Until now, I’ve designed the sigma-delta DAC (interpolation filter + modulator + 1bit internal DAC + analog lowpass filter) on Altium LiveDesign Eval Board (1bit internal DAC and lowpass filter were a part of Altium board).

Now I want to design a couple of interpolation filter sets and a variety of modulator structures for testing and analyzing, but this Altium board is insufficient for that and I must buy something else.

i would like to ask you for help...what i expect:

1. audio-in, audio-out (analog and digital) with audio codec and conventional ad and da converters (minimum 16bit and 44.1khz) – for general purposes.

and

2. ad and da converters without any codecs or dsp implemented, just converters (of course with inputs and outputs).

Big advantage of that Altium board was this 1bit stereo DAC with lowpass filter which was ideal for sigma-delta DAC project.

I’m looking for almost 3 weeks for some platform that will meet my requirments, but I can’t reach anything that cover in 100% my expectations...

I am very grateful for your help.

Best regards,

Marcin Lewandowski

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    the Altera Cyclone II DSP board has those features, though the plain ADC is AC coupled, or maybe better said RF coupled.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Thanks for reply.

    Ok, I've looked at this DSP kit with Cyclone II, but I have another questions...

    Why DSP kit with next generation of Cyclone (Cyclone III) costs 1000$ more? And what main differences are between those two kits? Workflow, usability, features? Maybe someone of You have used those two platforms and can say "empirically" about differences in use.

    Another issue are those Altera's partnership platforms. I was looking at Altium Nanoboards and Terasic DE2/DE3 with HSMC converters. What do You think about it in comparison with Altera's Cyclone II/III DSP Kits?

    Best regards,

    Marcin Lewandowski
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    the Cyclone III DSP board is much more powerful FPGA wise is probably the biggest difference. it also has ethernet, a display, 8x more SRAM, and supports HSMC daughter cards

    EP2C70 vs EP3C120

    LE: ~70k vs ~120k

    mult: 150 vs 288

    RAM: 1.1Mbit vs 3.9Mbit

    i don't know much about Altium's offerings.

    the DE2 doesn't have HSMC, but they do offer the ADA-GPIO for adding ADC/DAC to the DE2 and DE1. i don't know what the frequency response of their converter setups are. with the DE2 you're down to a EP2C35 device, ~35k LE, 35 multipliers, etc.

    the DE3 moves up to a Stratix III device with an HSMC connector so you could use the ADA-HSMC. the board doesn't feature an audio CODEC and i don't know if there's a solution available to add it (via GPIO headers or HSMC). this might be something you have to make.