Darrel, I just found your homepage
http://www.dlharmon.com WOW! What a project! 73 de Ulrich, DF6JB > -----Ursprungliche Nachricht----- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Darrell Harmon > Gesendet: Donnerstag, 17. Januar 2008 05:11 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Slightly OT: inexpensiveUSB > analog-digitalconverter? > > > 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. > _______________________________________________ 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.
