Re: [Discuss-gnuradio] Why not F/V and V/F Convertors ?!

[Hermann Gausterer]

hi saeed

On Tue, May 06, 2003 at 04:33:46AM -0700, Saeed Beyty wrote:
> Hi 
> 
> Why we dont use Frequency to voltage (F/V) or Voltage
> to Frequency (V/f) converter devices/chips in the
> front-end section?

with this sort of demodulator you can of course demod
(= receive) FM signals (per definition), a F->V chip
is nothing more than a (simple) FM demod.

you CANNOT demod an even simpler AM signal, or 
any of the nowerdays used modulationtypes like
QAM 

for digital signals, you can demod. FSK signals
but no QPSK 

> by this method there is no need to those expensive,
> high speed A/D converters to sampple the high
> frequency signals, nor the high speed CPUs to perform
> the time-comsuming FFT task.

but with this type of operation you can be sure, that
every new "narrow" band type of modulations is only
a software update away from working

i am open for any comments :-)

mfg hermann