Forums

general fsk question

Started by frumious January 22, 2009
I am trying to understand fsk demodulation in general.  Is there an
industry standard set of specific demod schemes or just classes of
particular methods (i.e. matched filter, correlation, coherent vs
non-coherent) that are invoked on a project by project basis? 


On Jan 22, 11:20 am, "frumious" <josh.sonn...@gmail.com> wrote:
> I am trying to understand fsk demodulation in general. Is there an > industry standard set of specific demod schemes or just classes of > particular methods (i.e. matched filter, correlation, coherent vs > non-coherent) that are invoked on a project by project basis?
Well, you can look at several industry standards that use FSK, for example the Caller ID standard, old Bell 103 and 202 standards, and the Emergency Alert System of the US NOAA. Keep in mind that typically, standards do not say how to receive / demodulate a signal, it just says how the signal should look like. You'll have to look at actual implementations.

frumious wrote:

> I am trying to understand fsk demodulation in general. Is there an > industry standard set of specific demod schemes or just classes of > particular methods (i.e. matched filter, correlation, coherent vs > non-coherent) that are invoked on a project by project basis?
The trivial method of FSK demodulation is some kind of discriminator either in a passband or in the baseband. Of course, there are the better approaches, however the discriminator is the most common. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
On Thu, 22 Jan 2009 10:20:10 -0600, frumious wrote:

> I am trying to understand fsk demodulation in general. Is there an > industry standard set of specific demod schemes or just classes of > particular methods (i.e. matched filter, correlation, coherent vs > non-coherent) that are invoked on a project by project basis?
The latter. What you do depends to a great extent on the difficulty of the channel and the amount of money you have to spend on receivers. -- http://www.wescottdesign.com