16384 Hz tone on TV signal?

While I was analysing some audio from my TV (plugged into my AV receiver
with record out plugged into my sound card) with Audacity, I noticed that
instead of having just one pilot tone at 15625 Hz caused by the line
deflection it had another at 16384 Hz as well.

What is the cause of the 16384 Hz tone? It's not the AV receiver since I
recorded some stuff from the radio tuner and that is fine apart from the
19000 Hz stereo reference pilot tone (although on Radio 3 there is also a
15625 tone on live classical music, but Radio Northampton is clean.)

16384 is 4000 hex so I think is must have something to do with something
digital. This tone is there irrespective of what channel or source I'm
watching so it must be something to do with the TV (Panasonic 28" 16:9 about
6 years old).

Anyone got any ideas?

"Agamemnon" wrote in message
. uk...
While I was analysing some audio from my TV (plugged into my AV receiver
with record out plugged into my sound card) with Audacity, I noticed that
instead of having just one pilot tone at 15625 Hz caused by the line
deflection it had another at 16384 Hz as well.

What is the cause of the 16384 Hz tone? It's not the AV receiver since I
recorded some stuff from the radio tuner and that is fine apart from the
19000 Hz stereo reference pilot tone (although on Radio 3 there is also a
15625 tone on live classical music, but Radio Northampton is clean.)

16384 is 4000 hex so I think is must have something to do with something
digital. This tone is there irrespective of what channel or source I'm
watching so it must be something to do with the TV (Panasonic 28" 16:9
about 6 years old).

Also the tone is not there when I connect my Freeview box directly to the
computer.


Anyone got any ideas?

Agamemnon wrote:


What is the cause of the 16384 Hz tone?

32,000 - 15,625 = 16,375 (9Hz off?)


--
Adrian C

Agamemnon wrote:
While I was analysing some audio from my TV (plugged into my AV receiver
with record out plugged into my sound card) with Audacity, I noticed
that instead of having just one pilot tone at 15625 Hz caused by the
line deflection it had another at 16384 Hz as well.

What is the cause of the 16384 Hz tone? It's not the AV receiver since I
recorded some stuff from the radio tuner and that is fine apart from the
19000 Hz stereo reference pilot tone (although on Radio 3 there is also
a 15625 tone on live classical music, but Radio Northampton is clean.)

16384 is 4000 hex so I think is must have something to do with something
digital. This tone is there irrespective of what channel or source I'm
watching so it must be something to do with the TV (Panasonic 28" 16:9
about 6 years old).

Anyone got any ideas?


Possibly caused by the NICAM decoder of the television?

Glenn...

"Adrian C" wrote in message
...
Agamemnon wrote:


What is the cause of the 16384 Hz tone?

32,000 - 15,625 = 16,375 (9Hz off?)


A few years ago before TFTs reigned supreme one could often hear audible
whistles on studio based output. I certainly remember it on Radio 4
I always assumed it was line timebase products being radiated from
CRT monitors abd being picked up by the ribbon mic.
Was I right?
--
Graham

%Profound_observation%

In article ,
Graham. wrote:


"Adrian C" wrote in message
...
Agamemnon wrote:


What is the cause of the 16384 Hz tone?

32,000 - 15,625 = 16,375 (9Hz off?)


A few years ago before TFTs reigned supreme one could often hear audible
whistles on studio based output. I certainly remember it on Radio 4
I always assumed it was line timebase products being radiated from
CRT monitors abd being picked up by the ribbon mic.
Was I right?

You could well have been. I know a 15kHz top cut filter was inserted in
N1's output to stop it getting to Crystal Palace on the line feed. R4, in
mono, probably didn't have a top cut filter.

--
From KT24 - in "Leafy Surrey"

Using a RISC OS computer running v5.11

"Glenn Millar" wrote in message
...
Agamemnon wrote:
While I was analysing some audio from my TV (plugged into my AV receiver
with record out plugged into my sound card) with Audacity, I noticed that
instead of having just one pilot tone at 15625 Hz caused by the line
deflection it had another at 16384 Hz as well.

What is the cause of the 16384 Hz tone? It's not the AV receiver since I
recorded some stuff from the radio tuner and that is fine apart from the
19000 Hz stereo reference pilot tone (although on Radio 3 there is also a
15625 tone on live classical music, but Radio Northampton is clean.)

16384 is 4000 hex so I think is must have something to do with something
digital. This tone is there irrespective of what channel or source I'm
watching so it must be something to do with the TV (Panasonic 28" 16:9
about 6 years old).

Anyone got any ideas?


Possibly caused by the NICAM decoder of the television?

I thought the NICAM sample rate was 32000 Hz.


Glenn...

"Adrian C" wrote in message
...
Agamemnon wrote:


What is the cause of the 16384 Hz tone?

32,000 - 15,625 = 16,375 (9Hz off?)

Ah, beating between the NICAM sample rate oscillator and the deflection
oscillator. But why would it leak into the audio out. Line defection uses
huge power transformers. NICAM shouldn't need something that powerful.



--
Adrian C

On Jun 24, 9:46*pm, "Agamemnon" wrote:
"Adrian C" wrote in message

...

Agamemnon wrote:

What is the cause of the 16384 Hz tone?

32,000 - 15,625 = 16,375 (9Hz off?)

Ah, beating between the NICAM sample rate oscillator and the deflection
oscillator. But why would it leak into the audio out. Line defection uses
huge power transformers. NICAM shouldn't need something that powerful.





--
Adrian C- Hide quoted text -

- Show quoted text -

The BBC used to use inband data on certain networks for switching
purposes, the other lot used to inject tone for programme path
monitoring.

Both were known to interfere with remote channel changing on early
'Tuning fork' Sony TVs which had an exceptionally good audio response

UKM