[TenTec] Corsair II noise blanker

[Bob McGraw - K4TAX]

Not really.  Or I would hope not.  To some extent, SSB voice can be viewed 
as short pulses at random intervals and CW is very long pulses at long to 
moderate intervals.

When one examines noise we find that atmospheric noise is usually a very 
broad pulse at rather long intervals.   We find ignition noise a broad pulse 
at rather long intervals by comparison. And we find line noise to be very 
short pulses at fast intervals.  Electric fence pulses are short pulses but 
at long intervals.

One must look at the length of the pulse and the rate of the pulse 
occurrence.  For AC line noise the pulse is usually 180 times per second and 
is very repetitive in time.  While atmospheric noise is usually pulses of 1 
to 2 sec in length but only at 5 to 15 second intervals.  Electric fence 
pulses are usually 200  to 400 milliseconds in length but occur every 1 or 2 
seconds.

The advantage to hardware noise blankers is they basically are a stand a 
lone process while those embedded in software rely on the processor to 
recognize the noise and then it has to look up the noise table and then take 
some action based on the noise that best fits.  In general software embedded 
noise blankers work best on things that are slow by comparison or things 
that don't change such as line noise.  It takes a totally different system 
to attack line noise. However the easy part of line noise is the frequency 
is known and the repetition rate is known.

The Noise Blanker objective is to mute the receiver to some degree of 
completion and at precicely the correct time but no so long as to punch a 
hole in the audio.


Confused?   I am.

73
Bob, K4TAX



----- Original Message ----- 
From: "Richards" <jrichards at k8jhr.com>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Friday, March 28, 2014 5:35 PM
Subject: Re: [TenTec] Corsair II noise blanker


>
> Do NB circuits have differing impact/utility/effect
>  on CW vs SSB vs data signals?
>
> -------------------- K8JHR  -----------------------
>
> On 3/28/2014 7:59 AM, Bob McGraw - K4TAX wrote:
>> The hardware optional NB for the Eagle does eliminate the pulse
>> ignition/injector noise in my truck mobile and it does not punch holes
>> in the audio.
>>
>
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