Karim Lakhani writes:
> sorry for the ignorance but what is DSP.
> I'm currently studying to get my license and this doesn't ring a bell in 
> the
> information I studied.

	I don't know if anybody answered this question off the
list, but DSP stands for Digital Signal Processing. In DSP, an
audio or even an RF signal is converted in to a stream of digits
which represent the voltage levels and polarities of the signal
being processed at a given moment.

	As an example, compact disks are based on a stream of
44,200 16-bit numbers per second for each audio channel. A
16-bit number has 65,536 possible values from 0 all the way up
to 65,535. Those digits represent voltages that range from no
voltage at all up to whatever the full voltage is for the
system.

	A DSP device is a very fast computer that can take that
bit stream and process all those numbers in such a way as to
achieve some particular goal such as to remove noise or maybe to
add an echo effect or even convert tones in to computer data
such as is what happens with modern decoders for PSK31 or RTTy.

	Sorry for the long explanation, but DSP is not simple.

	I am kind of surprised that very basic DSP questions
aren't in at least the Extra Class test.

	While DSP applications are highly mathematical, the
mechanics for inputting signals in to a DSP device or converting
those digits in to meaningful signals are fairly easy to
understand and appreciate.

Martin McCormick WB5AGZ  Stillwater, OK 
Systems Engineer
OSU Information Technology Department Telecommunications Services Group