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Discussion Starter · #1 · (Edited)
Hi,

A little question about the log sweep equation used in REW.

following the Farina deconvolution to extract Hn.

delta t between H2 and main impulse is done by:
delta t=T.(ln(N)/(ln(f1/f2)
N=order of harmonic,f1 end,f2 start,T lenght of sweep in sec.

for a 20 to 20KHz,5.9 seconds sweep:
H2 is 600ms before impulse (according Farina equ.)

in REW,the same sweep gives 340 ms between H2 and impulse.

is it a non standard log sweep ?


Thierry.
 

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The overall measurement time REW displays includes silent periods at the start and end of the sweep, the duration of the sweep itself is about 1.1s less. The picture is a little more complicated if the selected start frequency is below 10 Hz, in that case REW actually starts the sweep at DC with an initial linear sweep to approx 10 Hz and then transitions to a log sweep from there, to avoid spending a disproportionate time at very low frequencies.
 
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