John Miles wrote: > Is it just me, or is there a huge hole in the DAQ marketplace for a > high-resolution, low-noise, low-to-moderate cost, _medium_-speed acquisition > dongle? > > I've been planning to build a 100+ dB 24-bit USB DAQ interface around the > AD7760 for some time now, which would be good from DC-1 MHz. That would be > something like having a high-end sound card input with a 2.5-megasample ADC > instead of an audio ADC. > > The only thing that's stopped me so far is the FPGA and USB interfacing > work... > > -- john, KE5FX > I would certainly consider building one if you designed it and made gerber files or boards available.
I am currently finishing up a project with a 125 MHz 16 bit ADC and an FPGA digital down converter. The output rate is similar to what you would have (32 bit IQ at 500 kHz, so 4 MB/s). This does not seem very difficult with USB 2.0, but actually is quite difficult. I did 3 revisions of my board. The ADC and FPGA worked perfectly on the first revision, and the second two revisions were due to USB interface problems. I tried the Cypress FX2 and had nothing but problems with it. I am now using a Blackfin DSP and PLX NET2272 USB chip as the PC interface. It works well. I have written a spectrum analyzer application for it and plan on doing some software defined radio work with it soon. Whatever you do, it would be best if the sampling rate could be locked to an external 10 MHz input. I did that with my board and expect to write software in the next few months for frequency measurement. Darrell Harmon, KI4MVK _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
