noise cancel

[peterdk]

Hi all !
Is there somebody in here who can explain how the noise cancel really works. I seem to reckon, that this issue where debated a long time ago. But I cant find the tread again.
Is it so that when you use the noise cancel, that you always or almost end up on channel 15. And how does that effect your multifrequence ability.

Kind regards and happy hunting to all of you.

Peter

 

[Ev from somewhere]

I don't think it effects permformance. HH Ev

 

[Chris(SoCenWI)]

Peter,

Noise cancel shifts the transmitted frequencies by a small amount, then listens on the recieve side for signals, then shifts again and listens. The frequency shift that has the least number of signals is selected as the quietest channel. Noise cancel is used to try lessen the effect of ambient Electromagnetic Interference(EMI). For some types of EMI this is very effective, but most EMI is caused by Power lines and it has a much harder time eliminating this.

Next time you are out detecting hold the search coil a couple of inches away from your head while wearing your headphones. Hit noise cancel, the search coil will induce a signal in your headphones speakers that you can hear; you can hear it doing the frequency shift.

The Explorer uses only a couple or three different frequency square waves on the transmit side to generate the 23(?) receive frequencies. A couple of people posted oscilloscope shots of this years ago. You could also see the effect of noise cancelling.

If I remember correctly there where some channels that used more or less of the frequencies; don't think this makes any performance diferences.

Chris

 

[peterdk]

TX For the reply
Kind regards and happy hunting
Peter

 

[James N.D.]

n/t

 

[Captain Kirk]

Peter,

I just posted some thoughts on this subject on the Minelab Classroom forum. That may be of some interest.

HH,
Glenn

 

[Chris(SoCenWI)]

n/t