On Saturday 27 February 2010, Tim E. Real wrote: >On February 27, 2010 07:50:07 pm Gordon JC Pearce wrote: >> On Sun, 2010-02-28 at 01:41 +0100, [email protected] wrote: >> > On Sun, Feb 28, 2010 at 12:40:00AM +0000, Gordon JC Pearce wrote: >> > > I wanted a very simple SDR with jack inputs and outputs for a >> > > demonstration I was doing. I had a look at the DSP guts of dttsp and >> > > quisk, and sat down to code. >> > >> > Forgive my ignorance, but what is an SDR ? >> >> Software-Defined Radio. Basically you downmix incoming RF to the audio >> range with two mixers fed 90 degrees out of phase. You can then munge >> this in various different ways to tune and demodulate various different >> radio signals. >> >> Gordon MM0YEQ >> >> _______________________________________________ >> Linux-audio-dev mailing list >> [email protected] >> http://lists.linuxaudio.org/listinfo/linux-audio-dev > >I read about this in Nuts And Volts magazine. >They describe in some detail how SDR works and neat DSP techniques > in general. >I searched the web but could only seem to find Windows related stuff. >Some more Linux stuff would be cool. >One still needs to build or buy a front-end first though, right? > >Tim.
Build it. In 1975, RCA was making an IC for the FM detector that claimed <0.1% distortion and at least a 60db SNR for tv and fm radio rx use, the type CA3089-E. They were about $3 the last time I bought a onsie. 14 pin dip package. I would imagine that even better integrated circuits are available today for that. That one needed a superhet front end that could give it 400 microvolts to achieve that <0.1% THD, and delivered about 400 millivolts of audio. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) When God endowed human beings with brains, He did not intend to guarantee them. _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
