Fwd: Noise cancelling experiment
I have found a method to look at the difference of two signals.
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Subject: Noise cancelling experiment Date: Tue, 27 Nov 2012 12:34:41 +1100 From: edgar <edgarjtwining@...> To: firstname.lastname@example.org <email@example.com>, firstname.lastname@example.org <email@example.com>
An experiment was conducted to see if some noise could be cancelled using the signals from two receivers and Spectrum Lab software.
Winradio Excalibur SDR and two instances of Spectrum Lab, and two sound cards.
There are three receivers in the Excalibur SDR, and two of these were set up in CW mode with an offset of 500 Hz.
Band width was set to 10 Hz.
The output of one receiver was fed to channel A and the second to channel B of the sound card.
One receiver was set to the frequency of the signal, the little dark grey box at 229.6 kHz.
The second receiver's frequency was set up just next to the first, but receiving noise.
The little square grey box, just above the "z" in "kHz".
This is the NDB signal, 230 kHz NIE Nile, Tasmania on the receiver's waterfall.
(not at the same time as the images below)
An audio cable then was connected from the first sound card output into a second sound card's input.
Two instances of Spectrum Lab were used to compare the results with screen captures.
The "Enable amplitude and phase adjustment for I/Q input was enabled."
The waterfall signal was set to L5 where the two signals were added together.
With the I/Q input phase adjustment, located in the ADC box, set at 180 degrees this was the result.
With the I/Q input phase adjustment set at 0 degrees this was the result.