Missing factor 1/2 and 1/sqrt(2) ?

[fincardona]

Hi,

Is there a missing factor 1/2 in the computing of WNL in the following lines of code:

striptease/striptease/Spectrum tools help.Rmd

Lines 102 to 103 in bccffbe

	print('White noise level from spectrum = %4.3f, '
	'variance = %4.3f' % (wnl*samp_freq, np.std(noise)**2))

striptease/striptease/Spectrum tools help.Rmd

Lines 153 to 154 in bccffbe

	print('White noise level from spectrum = %4.3f, '
	'standard deviation = %4.3f' % (wnl*samp_freq, np.std(noise)**2))

and a factor 1/sqrt(2) in the following ones:

striptease/striptease/Spectrum tools help.Rmd

Lines 82 to 83 in bccffbe

	print('White noise level from spectrum = %4.3f, '
	'standard deviation = %4.3f' % (wnl*np.sqrt(samp_freq), np.std(noise)))

striptease/striptease/Spectrum tools help.Rmd

Lines 133 to 134 in bccffbe

	print('White noise level from spectrum = %4.3f, '
	'standard deviation = %4.3f' % (wnl*np.sqrt(samp_freq), np.std(noise)))

?

Furthermore, it is not to clear to me which are the real dimensions of WNL. Are they: amplitude / sqrt(freq) or power / freq ?
I think one should decide to refer either to the first as WNL and to the second as WNL squared or to the first as sqrt of WNL and to the second as WNL.

Thanks

[fincardona]

I found also that you plot 2*noise_properties[0]:

striptease/striptease/Spectrum tools help.Rmd

Line 229 in bccffbe

pl.loglog(spec['frequencies'][1:], np.zeros(len(spec['frequencies'][1:]))+2*noise_properties[0])

striptease/striptease/Spectrum tools help.Rmd

Line 266 in bccffbe

pl.loglog(plot_freqs, np.zeros(len(plot_freqs))+2*noise_properties[0])

striptease/striptease/Spectrum tools help.Rmd

Line 282 in bccffbe

pl.loglog(spec['frequencies'][1:], np.zeros(len(spec['frequencies'][1:]))+2*noise_properties[0])

which compensates for the missing factor 1/2 in the computation of White noise level from spectrum but, then, what do you have on the y-axis of the spectrum?