RE: [amsat-bb] Feedback removal in Software - An Idea!

[tlang@xxxxxxxxxxxxxxxxxxxx (Tony Langdon)]

Hello Walls,.

30 Jun 00 13:10, you wrote to 'Willmott, Paul':

 WR> One problem I see.  You want to be able to hear yourself.  Not as
 WR> important on the FM birds, but very important on the SSB birds.  A
 WR> complication (also on the SSB birds) is the downlink audio most likely
 WR> wont be EXACTLY the same as the uplink due to doppler shift.  Makes it
 WR> much harder for the DSP to cancel out the downlink audio - not
 WR> impossible, just harder.

Well, you could always design the thing to merely attenuate your audio.
Providing you stay out of the line of the speaker, it is possible to have
enough volume to hear what you sound like, without causing feedback.  I have
done this (with manual volume adjustments between Tx and Rx) at demos.

Another, even simpler suggestion:

Put the DSP on the speaker/headphone jack.  Wire up a headphone jack in the DSP
box _before_ the DSP, and have the speaker run via the DSP.  That way you can
plug in a set of phones for yourself, and the audience listens to the (echo
cancelled) speaker output.


Tony

.. when the computer asks you are you sure, ponder a moment
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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