GK IIIb scrambler spectrum
As to understand the way speech inversion takes place
we have made a brief spectrum screen shots.
Status: 4 November 2019
Hans Goulooze, showed me recently the features of an audio spectrum analyser.
Please bear the following in mind:
A scrambler or speech inverter reverses the spectrum
Hence: low frequencies being converted into a higher spectrum;
high frequencies being converted into a low frequency spectrum.
When, what is usually maintained in a communication chain - two scramblers being utilised, we convert the spectrum twice; consequently recovering the genuine speech spectrum again.
In other words: 2 x scrambling results in a recovered spectrum.
Measuring the audio output at the loudspeakers acoustically - after double scrambling, thus receiving a de-scrambled signal; measured at 700 Hz in/output
The small blip might be caused by a second order distortion; which had been cured by means of lowering the input signal level.
Measured at 1000 Hz in/output frequency though, with reduced input signal level
In/output frequency 1500 Hz
Now one scrambler being switched off
1000 Hz becoming reversed about 1000 Hz
1500 Hz is now generating the image of ca 600 Hz
(at a switching frequency of ca 2125 Hz)
By Arthur O. Bauer