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KB2VXA > DSP      13.07.03 02:53l 47 Lines 1952 Bytes #999 (0) @ WW
BID : 10172_WT3V
Subj: Re: G0FTD > DSP & impulse noise
Sent: 030711/0544Z @:WT3V.#CNJ.NJ.USA.NA #:10172 [Lakehurst] $:10172_WT3V
To  : DSP@WW

Hi Andy,

Without realizing it you have answered your own question.

To begin with, I experience the same noise you describe on all HF bands 
which is AC mains related in some way as during a recent power failure it 
disappeared completely. The DSP built into the IC-706 Mk2G when properly 
adjusted is completely effective against my being deafened by it, but DSP 
has it's limitations which are much greater when dealing with audio DSP 
than the more effective IF DSP. In either case the ears may be saved from 
the racket but wanted signals still suffer, such is the nature of the 

On the other hand I have a GE Mastr2 VHF LO FM rig converted to 6M with 
IF noise blanking which suffers not a whit from the effects of this 
noise. I have experience with several receivers which employ IF noise 
blankers, some more effective than others and once had an old CB rig in 
which it was completely innefective. The conclusion which may be drawn is 
simply that some are better than others. You just haven't found a good 
one yet.

As for answering your own question, since you say that a noise blanker 
which I assume works in the IF is innefective, what makes you think that 
using the exact same method in the audio chain will be? FYI, those noise 
reduction algorithms you speak of include the simplest one of all which 
does exactly what you're looking to do only it works with a digital train 
rather than audio. Remove the noise bits or remove the waveform, six of 
one and half dozen of the other.

Sorry there Andy, there is no such thing as perfection in the real world, 
only Perfection Nevada and they have giant killer worms. (;->)

73 de Warren, KB2VXA@WT3V.#CNJ.NJ.USA.NOAM


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Message timed: 05:51 on 2003-Jul-11 GMT

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