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Voice scrambler 2011-01-13

ElectroMaster

Administrator
ElectroMaster submitted a new article:

Voice Scrambler - With this circuit you can modify how your voice sounds by changing the pitch of your voice. This ci

With this circuit you can modify how your voice sounds by changing the pitch of your voice. This circuit can be connected to a phone and with a duplicate circuit on the end of the phone line, you can have a scrambled voice communication.

The way the circuit works is as follows: If we cut the circuit in half at the T2 transformer and include the LM324 on the left side, you will see that the LM324 portion of the circuit is a tone oscillator which shifts the frequency of all input signals to a...
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cr0sh

Member
Hmm - if you added digital pots for Tune 1 and 2, connected them to a microcontroller with a pseudo-random number generator, and synced the changes with the other end somehow (maybe via a signal mixed into the audio?)...it might be pretty damn secure.
 
Last edited:

doc b.

New Member
Sounds neat, theoretically.
Would the circuitry required be more complex than the scrambler circuit shown?
Would it be as easy/difficult to acquire a schematic of the circuitry used in "secure" U.S. military fone lines, or available telefone-signal, scrambler-descramblers?
 

dougy83

Well-Known Member
Are there some junction dots missing perhaps? There's no feedback path.
 

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