 High frequency noise
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Joined: Apr 2003
Posts: 5,236
axiomite
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OP
axiomite
Joined: Apr 2003
Posts: 5,236 |
File this under knowledge learned in college and since lost.
What is the frequency of that high pitched sound eminating from CRT based televisions? The tv need only be on, not necessarily tuned to any station. Many people can't hear it, but I can, and I've often wondered what frequency that is.
Anybody know? I've googled and come up empty.
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 Re: High frequency noise
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Joined: Sep 2004
Posts: 11,458
shareholder in the making
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shareholder in the making
Joined: Sep 2004
Posts: 11,458 |
19KHZ if I remembr correctly....
::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::
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Re: High frequency noise
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Joined: Jun 2003
Posts: 6,833
axiomite
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axiomite
Joined: Jun 2003
Posts: 6,833 |
I have mentioned hearing the same noise to a few people and they looked at me like I was nuts.
Rick
"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud
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Re: High frequency noise
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Joined: Apr 2003
Posts: 16,441
shareholder in the making
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shareholder in the making
Joined: Apr 2003
Posts: 16,441 |
Actually, it's 15,735 Hz, the horizontal frequency of NTSC. The flyback transformer is the culprit.
EDIT: Incidentally you can get this figure by multiplying the number of lines of resolution (525) by the frames per second (29.97).
Last edited by pmbuko; 10/27/05 12:30 AM.
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Re: High frequency noise
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Joined: Mar 2005
Posts: 7,463 Likes: 1
axiomite
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axiomite
Joined: Mar 2005
Posts: 7,463 Likes: 1 |
Peter, you win the "nerd-for-the-day" award.
***********
"Nothin' up my sleeve. . ." --Bullwinkle J. Moose
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Re: High frequency noise
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Joined: Apr 2003
Posts: 16,441
shareholder in the making
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shareholder in the making
Joined: Apr 2003
Posts: 16,441 |
Thank you.
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Winner of the nerd-of-the-day award, October 26, 2005
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Re: High frequency noise
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Joined: May 2003
Posts: 2,185
connoisseur
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connoisseur
Joined: May 2003
Posts: 2,185 |
I've always heard it. very annoying...at least my hearing is still good. can't say the same for my memory.
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Re: High frequency noise
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Joined: Jul 2005
Posts: 353
devotee
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devotee
Joined: Jul 2005
Posts: 353 |
In reply to:
The flyback transformer is the culprit.
Further to this, there are also some inductors on the main board with ferrite cores encapsulated in plastic. The ferrite core develops a chip and the voltage running through the coil causes the ferrite chip to vibrate within the plastic casing at a high frequency. This frequency can vary from set to set (when it fails) and is extremely annoying. It usually occurs at a frequency lower than that of the flyback and is more audible (drives me nuts).
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Re: High frequency noise
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Joined: Mar 2005
Posts: 7,463 Likes: 1
axiomite
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axiomite
Joined: Mar 2005
Posts: 7,463 Likes: 1 |
Nice try, Bruce, but you cannot steal Peter's award from him so soon.
***********
"Nothin' up my sleeve. . ." --Bullwinkle J. Moose
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Re: High frequency noise
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Joined: Apr 2003
Posts: 16,441
shareholder in the making
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shareholder in the making
Joined: Apr 2003
Posts: 16,441 |
now that's funny. 
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