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Re: [K3] Spectrogram and the K3

Posted by alorona on Jul 09, 2012; 10:47pm
URL: http://elecraft.85.s1.nabble.com/K3-Spectrogram-and-the-K3-tp7558874p7558907.html

When you look at Delay1 through 5 in MONO mode in Spectrogram you see peaks and
nulls in the frequency response. Spectrogram is only able to show the magnitude
and not the phase of signals, so from what was learned from AFX = Bin we saw
that the result of adding L + R as vectors can result in cancellation.

Similarly in Delay1 through 5 we are seeing the L and R noise signals adding
together and cancelling each other out at regular intervals -- resulting
in nulls in the frequency response. The *spacing* between the nulls can tell us
something. I measured the spacing as follows:

Delay1 :  500 Hz
Delay5 :  100 Hz

The nulls are caused by two signals, L and R, at the same frequency but shifted
in time, and as they combine their vector sum causes the nulls. The time delay
between L and R is easy to calculate based on our measurements:

Delay1 = 1/500 = 2 msec

Delay5 = 1/100 = 10 msec

That's my best guess as to the actual delay values.


Al  W6LX
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