Want a daughter card with DC signals

[Altera_Forum]

Hey guys, 

I am searching for a ADA daughter card for my cyclone 3 dev board. Particularly I want it to be able to capture DC analog input and generate DC analog ouput, because I am going to use it for a control system. Originally I got one from Terasic, but soon I found that it has transformers on board which disable its DC capability. I have been searching a lot but could not find any with such kind of capability. Has anyone here seen such kind of daughter cards? Thanks a lot  Best, Xuemeng

[Altera_Forum]

--- Quote Start ---  Hey guys, I am searching for a ADA daughter card for my cyclone 3 dev board. Particularly I want it to be able to capture DC analog input and generate DC analog ouput, because I am going to use it for a control system. Originally I got one from Terasic, but soon I found that it has transformers on board which disable its DC capability. I have been searching a lot but could not find any with such kind of capability. Has anyone here seen such kind of daughter cards? Thanks a lot  Best, Xuemeng  --- Quote End ---   Actually, I have the same problem. I am looking for a board which is capable to deal with low frequency signals for the control system.   Did you already get what you wanted?  If yes, would you please give me some hint?  Many many thanks.  Juan Ren

[Altera_Forum]

I found one on 4dsp.com which has a DC version for one of its daughter card AD250. But they will charge for $1700 for each with merely 2 channels of ADCs and DACs. If you are interested, you can send an email to Pierrick(pierrick.vulliez@4dsp.com). 

 Best, Xuemeng

[Altera_Forum]

I've made a daughtercard for the DE0 board with 8 channel in 2 channel out analog (along with a motor driver and PSP display interface). It's still in the prototype stage (slated to be used in a university course in the fall), so I couldn't sell or give one away at this point, but I would gladly field questions on the design. It's really quite a simple thing, and yes all the existing daughtercards are horrendously overpriced.

[Altera_Forum]

Considering the time consumed in making a daughter card, it may be a good choice to buy one if it's just around 1000 bucks. We are just gonna to use it for our research... Anyway, if your daughter card finally works, I am very interested. Can you tell me more details about you daughtercard? 

 Best, Xuemeng

[Altera_Forum]

the ADC is the ad7928  

http://www.analog.com/static/imported-files/data_sheets/ad7908_7918_7928.pdf  the DAC is the the ad5025 http://www.analog.com/static/imported-files/data_sheets/ad5025_5045_5065.pdf  Powered from 5V from the DE0, so its range is 0-5V. The one issue I have is that its SNR isn't extraordinary (like just 55db at full amplitude), due mainly to the noise on the DE0 board's supply rails.