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pra
Joined: 08 Jan 2005
Posts: 83
Helped: 5
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 09 Feb 2005 11:25 how to calculate SNR? |
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I know the Signal Transfer function (STF) and Noise Transfer Function (NTF) of my system. (both are in z transform)
how to calculate the SNR using this transfer functions
Thanku
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andreas1982
Joined: 29 Oct 2004
Posts: 32
Helped: 1
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| 09 Feb 2005 12:14 Re: how to calculate SNR? |
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SNR is signal noise ratio!
So you must calculate signal/noise!
Regards.
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kali
Joined: 20 Nov 2004
Posts: 13
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| 09 Feb 2005 18:31 Re: how to calculate SNR? |
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Hi,
It is signal power divided to noise power
usually in db
cheers
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andreas1982
Joined: 29 Oct 2004
Posts: 32
Helped: 1
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| 09 Feb 2005 23:01 Re: how to calculate SNR? |
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I forget to say that:
SNR=20 log (signal/noise)
or
SNR=10 log (power of signal/power of noise)
Ok?
Regards.
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brmadhukar
Joined: 21 Jun 2002
Posts: 844
Helped: 29
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| 11 Feb 2005 18:30 Re: how to calculate SNR? |
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Just using a transfer function you cannot.
You need numbers.
SNR depends on signal power and noise power. So in first step you need to know the Signal power input and also the noise density.
If your tf filters the spectrum. Some of the noise power will reduce but your NF adds some noise. Starting with this you will be able to find the SNR.
BRMadhukar
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ihab
Joined: 03 Jul 2004
Posts: 28
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| 11 Feb 2005 18:53 Re: how to calculate SNR? |
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| The S/N ratio is exceedingly difficult to measure without special (and very expensive) test equipment. For instance to test for S/N ratio could cost in the region of £25,000 for the equipment. A less expensive way is to introduce a special filter to exclude the video signal and measure the remaining noise, from which the S/N ratio can be calculated. However even this filter can cost in the order of £1,000. Neither of these methods are practical in the field on actual installations, even if the equipment could be afforded.
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