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Re: artifact in spectrogram analysis

Subject: Re: artifact in spectrogram analysis
From: "sainganrob" sainganrob
Date: Sat Jul 21, 2012 1:22 pm ((PDT))

--- In  "Avocet" <> wrote:
>

> I haven't looked at 24 bit recordings on my affordable Tascams, but I
> suspect that the least bits are noisy. For a start, no analogue input
> is likely to have a signal to noise ratio of 138dB if only because
> that takes it beyond thermal noise.
>

Not quite, remember, signals go above reference levels as well as below :)

A 150R, 20KHz BW, 20 degC source at a nominal 'Line Level' peak of +8dB re =
(0.775) is 139dB SNR.

A typical clip point for a Line Input stage is +20dB and so would equate to=
 a 151dB SNR.

As the chances of receiving a +20dB (or +8dB for that matter) signal with n=
othing but thermal noise are extremely small, I think its safe to assume th=
e Tascam's least bits will be noisy :)

Rob










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