RE: LF: Related Technical Query - Soundcard calibrator

["James Moritz" <J.R.Moritz@herts.ac.uk>]

Dear Andy, LF Group

I hate to throw a spanner in the works, but... A noise source of exactly
this type is discussed in Horowitz & Hill "The Art of Electronics" 2nd
ed., section 9.34. This gives the formula (in the form Andy has used)
Vrms^2 = Vpk^2 * 2 * BW /Fclock, (giving 224mV rms) which is different
by a factor of sqrt(pi) from the value Andy gets. I spent some time last
night trying to figure out which one is correct, and came out with a
reasonably convincing case for Horowitz & Hill's formula - if anyone is
interested, I will put it into an e-mail compatible form


Cheers, Jim Moritz
73 de M0BMU