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Signal Values - What do they mean?!


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Old 04-10-2008, 15:26
BobbyDon
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Join Date: Jul 2002
Location: Scotland
Posts: 75

Hi All,

I have a Sony Bravia TV and use the inbuilt freeview when watching channels. I am in a rented flat and have to use an internal aerial (which has an amplifier on it). I have it pointed out of the window and most of the time I get a decent signal. it does break up now and then.

I noticed on the Sony Bravia System Information Menu, as well as the signal level (bar showing signal strength), it also displays various values that can change, these are (with example values as:

Pre Viterbi (5.35 e-3)
Post Viterbi (0)
5s (4.58 e-3)
5s (0)
UEC (0)
COFDM AGC (234)

Am looking to perfect the position of the aerial and hoping I can do this by moving the aerial until I can get near the best values for each of the above.

Does anyone know what these mean and what values mean the best signal strength? I have looked online and can't find much information about this.

Cheers

Bob
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Old 04-10-2008, 22:50
Anti-Static
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Join Date: Nov 2006
Posts: 264

Pre Viterbi (5.35 e-3)
Post Viterbi (0)
5s (4.58 e-3)
5s (0)
UEC (0)
COFDM AGC (234)
Viterbi is a method of error correction used in digital transmission.
'Pre Viterbi' will relate to the errors detected on the incomming bitstream and 'post' will be the amount of errors after the viterbi correction algorithm has been applied. So you would want Post to be zero.
The 5s values will be the Viterbi measurements averaged over 5 seconds.
Not sure about UEC.
COFDM, coded orthoganal frequency division multiplexing is the method employed at the transmitter to combine all the data into one bitstream.
AGC relates to automatic gain control.

But then I could be wrong!!!!
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Old 21-12-2011, 02:48
Souriau
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Join Date: Jul 2000
Location: Newry,
Posts: 85

Can anyone tell me the technical info mean

Pre Viterbi_ 2.00 e-2____C/N____25____UEC____0
Post Vitrtbi_0__________5s_____0_____AGC__140

I know that Pre is signal from areial before correction and Post is after correction
C/N Carrier Noise?
UEC Uncirrected Error Control?
AGC Autonatic Gain Control?
and tell me what valuse show be idea

Thanks in Advance
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Old 21-12-2011, 15:43
MatthewColeran
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Join Date: Oct 2011
Location: Gateshead
Posts: 117
Can anyone tell me the technical info mean

Pre Viterbi_ 2.00 e-2____C/N____25____UEC____0
Post Vitrtbi_0__________5s_____0_____AGC__140

I know that Pre is signal from areial before correction and Post is after correction
C/N Carrier Noise?
UEC Uncirrected Error Control?
AGC Autonatic Gain Control?
and tell me what valuse show be idea

Thanks in Advance
C/N = a measure of the 'quality' of the signal. Minimum required is 25 but that should go up past 35 for a perfect signal. Its a ratio of the carrier signal to that of the noise that is also carried
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Old 21-12-2011, 22:57
jcsager
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Join Date: Dec 2008
Posts: 133
Hi All,

I have a Sony Bravia TV and use the inbuilt freeview when watching channels. I am in a rented flat and have to use an internal aerial (which has an amplifier on it). I have it pointed out of the window and most of the time I get a decent signal. it does break up now and then.

I noticed on the Sony Bravia System Information Menu, as well as the signal level (bar showing signal strength), it also displays various values that can change, these are (with example values as:

Pre Viterbi (5.35 e-3)
Post Viterbi (0)
5s (4.58 e-3)
5s (0)
UEC (0)
COFDM AGC (234)

Am looking to perfect the position of the aerial and hoping I can do this by moving the aerial until I can get near the best values for each of the above.

Does anyone know what these mean and what values mean the best signal strength? I have looked online and can't find much information about this.

Cheers

Bob
You want to aim to get the Pre-Viterbi figure or the first 5s number as low as possible on the worst multiplex. If you are not familiar with scientific notation for numbers, 5.35E-3 means 5.35 multiplied by 1/1000, i.e 0.00535. If the number after the E (the exponent) were -4 then that would mean it was 10 times smaller, i.e 0.000535. You want, firstly, the exponent to be as negative as possible and then the first part of the number to be as small as possible. So, for example, 9.9E-4 is smaller than 1.1E-3.
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