Do these things exist?
 

Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for selectivity
and demodulation?

Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for selectivity
and demodulation?

Dig around for some of the "software radio" projects.

http://www.gnu.org/software/gnuradio/gnuradio.html
http://ourworld.compuserve.com/homepages/jmitola/
http://volodya-project.sourceforge.net/SR/sr.php

There are plenty of others.

Basically, you take the IF signal, bandpass filter it down to a
reasonable bandwidth (as required to cover whatever modulation you're
dealing with), and then digitize it. The digitizer needs to have
enough bits of resolution to handle the range of IF signal amplitudes
you're expecting to see (adding an AGC in front can help matters a
lot), and needs to run at a sampling rate which is greater than twice
the IF bandwidth. You don't have to run the ADC at twice the sampling
rate of the IF signal frequency - just at twice its bandwidth
("undersampling").

Then, pull the data into your CPU and use FFT, lapped transforms,
wavelets, or whatever you want/need to do the demodulation.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for selectivity
and demodulation?

Dig around for some of the "software radio" projects.

http://www.gnu.org/software/gnuradio/gnuradio.html
http://ourworld.compuserve.com/homepages/jmitola/
http://volodya-project.sourceforge.net/SR/sr.php

There are plenty of others.

Basically, you take the IF signal, bandpass filter it down to a
reasonable bandwidth (as required to cover whatever modulation you're
dealing with), and then digitize it. The digitizer needs to have
enough bits of resolution to handle the range of IF signal amplitudes
you're expecting to see (adding an AGC in front can help matters a
lot), and needs to run at a sampling rate which is greater than twice
the IF bandwidth. You don't have to run the ADC at twice the sampling
rate of the IF signal frequency - just at twice its bandwidth
("undersampling").

Then, pull the data into your CPU and use FFT, lapped transforms,
wavelets, or whatever you want/need to do the demodulation.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for
selectivity
and demodulation?

A number of the better German car radios use this technique. Motorola and
Visteon/Ford are promoting chips which do this.

Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for
selectivity
and demodulation?

A number of the better German car radios use this technique. Motorola and
Visteon/Ford are promoting chips which do this.

Try www.flex-radio.com


"Richard" wrote in message
...
Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for selectivity
and demodulation?

Try www.flex-radio.com


"Richard" wrote in message
...
Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for selectivity
and demodulation?

I believe that the new Philips chipsets use DSP techniques for demodulation.
I also believe that this scheme is used in the Cambridge Audio T-500 tuner.
I do have one of these tuners, and it is the worst sounding unit out of my
collection. If it wasn't for the fact that it had a nice dual conversion AM
section, I would get rid of it.

Pete

"Michael" wrote in message
...
Try www.flex-radio.com


"Richard" wrote in message
...
Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for
selectivity
and demodulation?

I believe that the new Philips chipsets use DSP techniques for demodulation.
I also believe that this scheme is used in the Cambridge Audio T-500 tuner.
I do have one of these tuners, and it is the worst sounding unit out of my
collection. If it wasn't for the fact that it had a nice dual conversion AM
section, I would get rid of it.

Pete

"Michael" wrote in message
...
Try www.flex-radio.com


"Richard" wrote in message
...
Does a product exist that takes an FM IF signal input at 10.7Mhz and
produces audio output, having employed digital technology for
selectivity
and demodulation?