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