integrated ADC for Altera Devices

[ik1xpv]

Hello List,

Referring to the integrated DAC solution ( https://groups.google.com/d/msg/hermes-lite/ZazL8dYVU4w/dZqZoWSady0J )

I made some investigation how to integrate the microphone ADC into the FPGA.

I found some interesting web links related to integrated ADC for Altera Cyclone-IV Devices.

http://www.altera.com/technology/system-design/articles/2013/signal-conditioning.html

http://www.missinglinkelectronics.com/files/papers/MLE-Altera-DuE-Entwicklerforum2011.pdf

http://www.missinglinkelectronics.com/devzone/files/papers/MLE-TB20110419.pdf

I have not been able to find a free  balanced pair input in the BeMicroSDK + PCB v1.1  to test the  ADC input circuit described in the papers.

May be  designing a new PCB some pinout arrangement may be found to free a balanced pair input.

73

Oscar

IK1XPV

[Steve Haynal]

Hi Oscar,

Thanks for the links. Sorry I haven't had time to read them yet. I'm glad you are thinking about ADC input. Here a just a few comment that came to mind. First, if the balanced pairs you need are the LVDS (low voltage differential signaling) pins, then there may be more complications that just finding a free pair. The Cyclone pins belong to a bank, and the entire bank has to be the same standard. You can't have just one LVDS pair and leave the others as single ended. Second, your desire for audio ADC/DAC makes me think of the new MAX 10 devices which have integrated ADC/DAC capable of audio speeds. There is a BeMicro MAX10 but it doesn't have the required capacity. Altera is supposed to release a larger capacity MAX 10 device this month which will have enough capacity.

Good luck with the ADC experiments!

73,

Steve

KF7O

[ik1xpv]

Hi Steve,

Many thanks for your post. It clarify to me the problem in using LVDS. I tried with a single ended input but of course it has some hysteresis and it does non give a reasonable  voice quality. I will look for MAX 10 evolution.

73,

Oscar

IK1XPV