I'm working on an SDR using the Tayloe method of decoding I and Q from the incoming RF.
But it requires a 4:1 analog multiplexer with some difficult requirements that I'm having a hard time finding. There is a reference design out there using a discontinued dual 4:1 analog MUX, I'm hoping to find something with specs at least close to that one.
It has the strange requirement, for an analog MUX, of requiring the ability to switch between channels very quickly. MUXes are usually optimized for bandwidth through the switch, and have switch settling times on the order of 100nS to 10uS.
There are so many manufacturers to search...
This looks promising! This design uses a Fairchild FST3253 analog MUX with specs that look good. Propagation delay 0.25nS, Ton and Toff between 1 and 5nS when run on 5V. 4 ohms, and it is a dual 4:1 port so they can be connected in parallel to minimize resistance. And only 65 cents from Digikey!
http://www.wb5rvz.com/sdr/ensemble_rx_ii/06_mix.htm
http://www.fairchildsemi.com/ds/FS/FST3253.pdf
Any suggestions?