Didier, check the HPSDR Janus baseband interface and related bits. It's a very good ADC on a board designed with time-nuttish care and can do up 192ksps. The downside is that it doesn't have a soundcard interface; the upside is that the hardware and SDR software that alkmto it are all open source.
http://openhpsdr.org/janus.php John On Jan 14, 2012, at 2:13 PM, shali...@gmail.com wrote: > Here is a common misconception. Most consumer grade "24bit" sound cards only > have 16 bit ADCs but 24 bit equivalent DACs (most of them are actually 1bit > DAC with oversampling.) > > You have to spend a pretty penny to get a 24 bit ADC running at multiples of > 44ks/s. > > Further, the very poor DC performance of the typically sound card 16 bit ADC > is hidden by the analog and digital filtering of the card and the driver. > > If anyone has an inexpensive (<$100) sound card with true 24 bit ADC (if they > are capable of DC, so much the better), please let me know because I have > been looking for one. > > Didier KO4BB > > PS: to remain on topic, I agree with the principle of using a PC to > breadboard something, as long as the hardware interface remains simpler than > a cheap microcontroller, bit it is easy to get carried away and build > PC-based hardware for the purpose of running a test, and having to redo all > from scratch to convert it to a uC solution for the final application. > > > Sent from my BlackBerry Wireless thingy while I do other things... > > -----Original Message----- > From: Chris Albertson <albertson.ch...@gmail.com> > Sender: time-nuts-boun...@febo.com > Date: Fri, 13 Jan 2012 08:15:42 > To: Discussion of precise time and frequency measurement<time-nuts@febo.com> > Reply-To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Subject: Re: [time-nuts] FE-5680A Mechanical Question > > On Fri, Jan 13, 2012 at 3:19 AM, <ewkeh...@aol.com> wrote: >> What we know is that you can set the Rb in 7 E-13. Dithering would allow >> even closer setting, the question is what rate will the Rb accept with out >> loosing lock or deterioration of the performance. Some one should explore >> that. I am still waiting to se some aging. Taking the 10 MHz output and than >> use an analog loop and something like a Morion OCXO and you have the best of >> all. >> Digitally controlling the Rb will cut the cost of the control loop in half. >> For $10 in parts and a PC board for less than $10 using Shera like >> controller can be realized. What is needed is some one able to do the PIC. >> If some one is interested and able, please contact me off list. A low cost >> GPS or a 1 pps output of a Tbolt be perfect source. >> Bert Kehren > > Don't use a PIC for the prototype. A desktop PC could work as well > and everyone here already has one. Connect the FE5680 to the PC's > serial port and send commands to adjust it. The PC also needs to be > able to read a voltage. Many already have audio input with 24-bit > ADC chips. > > Later you can move the C code from the PC pretty much directly to an > AVR. PICs typically use assembly language, that is harder and limits > the number of people who can contribute changes to the code. But you > can start with a PC, maybe running Linux or BSD. > Chris Albertson > Redondo Beach, California > > _______________________________________________ > 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. _______________________________________________ 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.
