Software Defined Radio on Xilinx Virtex 4

Hello, Let me right again in this forum on the same topic. But know in English. Whatever my English is very poor. I am working for about 4 month's ego with an ML405 Xilinx Virtex 4 board and I wanted now to implement a Software Defined Radio (SDR). I understand everything that relates to SDR (theory, operation, Etc..) Very good. Likewise, I also understand VHDL and VERILOG. Now I would like to know if someone is thus also employs An SDR Board on the above (or others) to implement appropriate Experience exchange.

In following a detailed overview of what I Made now:

First, I strive times only to receive an AM signal.

Hardware is on the board as much: DA converter (LM4550) National and an external A / D converters (LTC2208) by Linear Technology. I have prepared all software developed (ADC.vhd, DAC.vhd, DDC.vhd ,...)I make already the simulation. Now, I must try my signals: and with a Function generator, I would like to generate a sine wave, and then the sine wave through the FPGA with the process by the AD and DA converters. I Am suppose to have the same signals again after the DAC.

Example. Sine (1Khz) ----> ADC -> FPGA ---> DAC ---> sinus (1Khz) I can hear something (signal) at the output (by the DA converter) with the Headphones. However, I cannot measure it with the oscilloscope. I had already tried without much success, and ask what the problem Lie? Whether it down sampling, or rather in a Clock functions?

Did someone get an idea or a tip for me?

I look forward to all suggestions and thank you in advance...

Chindji

Reply to
auguste.chindji
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Hi ,

Not enough information. in the chain

Sine (1Khz) ----> ADC -> FPGA ---> DAC ---> sinus (1Khz)

What are the contents of FPGA? Is it just storing the data from ADC in buffer and transfering to DAC?

What is the peak to peak of the sine wave ? What analog circuitry is the sine wave going through?

What is the format of the data comming out of ADC? Any Scaling?

BR Rate

Reply to
ratemonotonic

The FPAG don't have any contents its just storing the sine wave from the ADC and give it out through the DAC.

What analog circuitry is

The sine wave it's just going directly to the ADC

LVDS (Low Voltage Differential Signaling)

Reply to
auguste.chindji

This would be a good subject to post on comp.dsp -- you'll get about equal interest from this newsgroup and sci.electronics.design, but you'll get a lot of experienced folks on your side on comp.dsp.

Your post is vague on just what you _do_ see on your oscilloscope, so I have a suggestion to start with: figure out what the signals should be going into each stage of your circuit, then build up the application one stage at a time, verifying functionality at each step. You can work from either end: you can synthesize a good input signal for the last stage and make sure the DAC's do the right thing, then add in the second to last, etc. Conversely, you can bring the output of intermediate stages to the DAC and make sure the signals look right.

This is all just basic debugging, but it can be hard to remember to do when you're working on a software/firmware app.

--
Tim Wescott
Control systems and communications consulting
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Reply to
Tim Wescott

Right My question about the peak to peak of the signal and the format of the ADC was to do with saturation issues. Check if the ADC is saturating or not.

Are you getting anything on the scope?

BR Rate

Reply to
ratemonotonic

You need to do step-by-step module addition and debugging. It is better to figure out the method to measure in oscilloscope. Else, it is going to be tough.

Karthik Balaguru

Reply to
karthikbalaguru

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