[Discuss-gnuradio] SDR Radio Telescope Receiver

[Phil Behnke]

Hello All,

I'm currently an undergraduate engineering student at Grand Valley State University.  For my senior design project, I'm working on designing a SDR-based radio telescope to compliment the NASA RadioJove project (a direct conversion receiver for use in radio astronomy).

In a nutshell, the receiver must be able to receive an AM signal with a center frequency of 20.1MHz and a bandwidth of 1MHz.  On the software side of things, we need to be able to plot signal strength as a function of time and frequency in real time.  We are planning to use analog mixing to get an IF centered around 500kHz and 1MHz bandwidth.  The IF would then be sampled that with a 14-bit ADC clocked around 4MHz.  The output of the ADC would then be sent to some kind of controller (ie. FPGA, microcontroller, etc) which would do a little bit of digital down converting to get the signal into its I and Q centered around DC and send it over USB to the host PC.

While I am not completely against using an FPGA in the design of our receiver, I would really like to use a fast microcontroller, PSoC, or similar device as I have much more experience programming in C than I do in HDL.  Has anyone hear of a SDR receiver with 1MHz bandwidth using a microcontroller?  I was thinking along the lines of using a ARM Cortex M3 chip with high clock frequency (~80MHz), DMA, and external ADC clocked around 4MHz, but I'm not sure if the ARM chip would be fast enough to down convert all that data and send it over USB quickly enough.  If anyone has links to resources where this kind of thing has been done that would be awesome.

I'm very new to SDR development so any input would be greatly appreciated.

Thanks!

Phil