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@k8jhr.com>
To: "Discussion of Ten-Tec Equipment" <tentec@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.
___________________________________________________
/
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|