Orion I Noise Reduction Testing
===============================
Tested with NR settings of 1 and 9, firmware V1.373b5.
Testing performed in LSB mode, PBT = 0 Hz, BW = 2500 Hz
Steady input consisting of white noise plus a CW signal at 700 Hz.
A stream of 25 wpm dits was used, dit duration = pause duration = 50 ms.
Prior to each test, NR was "trained" to a different tone to ensure "fresh"
operation.
Actual audio files are enclosed, along with waveform and spectrogram displays.
Bandpass filtering action is obvious from spectrograms.
NR forms a bandpass filter around signal.
The bandwidth can be estimated to 500 Hz.
Both views show that it takes around 600 ms for NR to reach a steady state.
Therefore it is unable to follow actual CW code elements, or different parts of
speech.
Instead, NR adapts itself to the "average" signal spectrum.
Please go to http://www.geocities.com/va3ttn and download
the first file from the list (OrionNR1.373b5.zip 454,743 bytes)
73,
Sinisa YT1NT, VE3EA
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