I am interested in drawing the spectrum of signal after passing the quantizer.

My system consist of:

sine wave source --> sampler --> sample and hold --> quantizer.

I know that quantizer add noise to original signal. The equation to determine SNR is
SNR = 6.02*N + 4.77+ 20*log10(LF)+ 10*log10(OSR), LF is loading factor and OSR is over sampling ratio factor.

My question is in which band of frequencies this SNR is valid. Is this valid only in -Fs/2 .... Fs/2.

Thank you!

 

I am interested in drawing the spectrum of signal after passing the quantizer.

My system consist of:

sine wave source --> sampler --> sample and hold --> quantizer.

I know that quantizer add noise to original signal. The equation to determine SNR is
SNR = 6.02*N + 4.77+ 20*log10(LF)+ 10*log10(OSR), LF is loading factor and OSR is over sampling ratio factor.

My question is in which band of frequencies this SNR is valid. Is this valid only in -Fs/2 .... Fs/2.

Thank you!

Sorry, but I don't understand why you have a sampler followed by a sample & hold, aren't they just one thing?

 

I am interested in drawing the spectrum of signal after passing the quantizer.

My system consist of:

sine wave source --> sampler --> sample and hold --> quantizer.

I know that quantizer add noise to original signal. The equation to determine SNR is
SNR = 6.02*N + 4.77+ 20*log10(LF)+ 10*log10(OSR), LF is loading factor and OSR is over sampling ratio factor.

My question is in which band of frequencies this SNR is valid. Is this valid only in -Fs/2 .... Fs/2.

Thank you!

I do not know what Loading Factor is. I do know the formula: SNR = 6.02*N + 4.77+ 10*log10(OSR), OSR is over sampling ratio factor; is only valid for conditions where the quantization noise is approximately white; that is uniform in power spectral density over the frequency range -Fs/2 .... Fs/2: where Fs is the sampling rate of the sampler. According to my observations and a literature search (both available); the conditions are:

1) There is absolutely no clipping (overflow).

2) The signal +28 dBrmsLSB or higher. (rms signal level at least 28 dB more than voltage of Least Significant Bit)

3) The data converter clock rate is not an integer multiple of the modulation rate.