Speech scrambler

Claim 2

A speech scrambler unit for use with a communication station having a speech signal originator, a speech signal reproducer, a radio frequency transmitter, a radio frequency receiver, and first switching means for alternately enabling said transmitter or said receiver, said scrambler comprising: input means for coupling to an output of said speech signal originator and an audio signal output of said receiver; output means for coupling to said speech signal reproducer and an audio signal input of said transmitter; speeCh coding means having input means and output means for coding and decoding speech signals applied to said speech coding means input means; first gating means coupled to said input means, said speech coding means input means, and said switching means for applying the signal generated by said speech signal originator to said speech coding means input means when said transmitter is enabled and applying the signal at said receiver audio output to said speech coding means input means when said receiver is enabled; second gating means coupled to said output means, said speech coding means output means, and said switching means for applying the signal at said speech coding means output means to said transmitter audio input when said transmitter is enabled and applying the signal at said speech coding means output means to said speech signal reproducer when said receiver is enabled; and second switching means for selectively defeating said speech coding means and applying the signal generated by said speech signal originator to said transmitter audio input and applying the signal at said receiver audio output to said speech signal reproducer.

Claim 3

The speech scrambler unit of claim 1 wherein said speech coding means comprises: an oscillator for generating a subcarrier signal; a balanced modulator coupled to said speech coding means input means; and a filter for attenuating the relative amplitude of signals having a frequency greater than that of said subcarrier signal coupled to the output of said balanced modulator and said speech coding means output means.

Claim 4

The speech scrambler unit of claim 2 wherein said speech signal originator comprises a microphone and said speech signal reproducer comprises a speaker.

Claim 5

A speech scrambler unit for use with a communications station having a speech signal originator, a speech signal reproducer, a radio frequency transmitter, a radio frequency receiver, and first switching means for alternately enabling said transmitter or said receiver, said scrambler comprising: a first input for coupling to an output of said originator; a second input for coupling to an audio signal output of said receiver; a first output for coupling to an audio signal input of said transmitter; a second output for coupling to said reproducer; speech coding means having an input and an output for coding and decoding speech signals applied to said speech coding means input; first gating means coupled to said first switching means, said first input, said second input, and said coding means input for delivering the signal present at said first input to said coding means input and isolating said second input from said coding means input when said first switching means enables said transmitter and delivering the signal present at said second input to said coding means input and isolating said first input from said coding means input when said first switching means enables said receiver; second gating means coupled to said first switching means, said first output, said second output, and said coding means output for delivering the signal present at said coding means output to said first output and isolating said coding means output from said second output when said first switching means enables said transmitter and delivering the signal present at said coding means output to said second output and isolating said coding means output from said first output when said first switching means enables said receiver; and second switching means for selectively defeating said processor and delivering said signal at said first input to said first output and delivering the signal at said second input to said second output.

Claim 6

A speech scrambler unit for use with a communications station having a speech signal originator, a speech signal reproducer, a radio frequency transmitter, a radio frequency receiver, and first switching means for alternately enabling said transmitter or said receiver, said scrambler comprising: a first input for coupling to an output of said originator; a second input for coupling to an audio signal output of said receiver; a first output for coupling to an audio signal input of said transmitter; a second output for coupling to said reproducer; speech coding means having an input and an output for coding and decoding speech signals applied to said speech coding means input; first gating means coupled to said first switching means, said first input, said second input, and said coding means input for delivering the signal present at said first input to said coding means input and isolating said second input from said coding means input when said first switching means enables said transmitter and delivering the signal present at said second input to said coding means input and isolating said first input from said coding means input when said first switching means enables said receiver; second gating means coupled to said first switching means, said first output, said second output, and said coding means output for delivering the signal present at said coding means output to said first output and isolating said coding means output from said second output when said first switching means enables said transmitter and delivering the signal present at said coding means output to said second output and isolating said coding means output from said first output when said first switching means enables said receiver; and second switching means for selectively defeating said processor and delivering said signal at said first input to said first output and delivering the signal at said second input to said second output.

Claim 7

The speech scrambler unit of claim 4 wherein said first switching means is manually operable.

Claim 8

The speech scrambler unit of claim 5 wherein said coding means comprises means for frequency inverting the signal applied to said coding means input means.

Claim 9

A communications unit comprIsing: radio frequency signal transmitting means; radio frequency signal receiving means; speech signal origination means; speech signal reproducer means; coding means having input means and output means for coding and decoding signals applied to said coding means input means; first switching means for rendering said coding means responsive to a signal from said origination means and said coding means nonresponsive to a signal from said receiving means when said first switching means is in a first state and rendering said coding means responsive to a signal from said receiving means and nonresponsive to a signal from said origination means when said first switching means is in a second state; second switching means for rendering said reproducer means responsive to the coding means output means and said transmitting means nonresponsive to the coding means output means when said first switching means is in said first state and rendering said transmitting means responsive to said coding means output means and said reproducer means nonresponsive to said coding means output means when said first switching means is in said second state; and third switching means for selectively defeating said coding means and rendering said transmitting means responsive to a signal from said origination means and rendering said reproducer means responsive to a signal from said receiving means.

Claim 10

A communications unit comprIsing: radio frequency signal transmitting means; radio frequency signal receiving means; speech signal origination means; speech signal reproducer means; coding means having input means and output means for coding and decoding signals applied to said coding means input means; first switching means for rendering said coding means responsive to a signal from said origination means and said coding means nonresponsive to a signal from said receiving means when said first switching means is in a first state and rendering said coding means responsive to a signal from said receiving means and nonresponsive to a signal from said origination means when said first switching means is in a second state; second switching means for rendering said reproducer means responsive to the coding means output means and said transmitting means nonresponsive to the coding means output means when said first switching means is in said first state and rendering said transmitting means responsive to said coding means output means and said reproducer means nonresponsive to said coding means output means when said first switching means is in said second state; and third switching means for selectively defeating said coding means and rendering said transmitting means responsive to a signal from said origination means and rendering said reproducer means responsive to a signal from said receiving means.

Claim 11

The communications unit of claim 7 further comprising fourth switching means for manually controlling the states of said first and second switching means.

Claim 12

The communications unit of claim 8 wherein said coding means comprises means for frequency inverting the signal applied to said coding means input means.

Claim 13

The communications unit of claim 9 wherein said frequency inverting means comprises: oscillation means for generating a subcarrier signal; a balanced modulator coupled to said coding means input means and said oscillation means; a filter for attenuating the relative amplitude of signals having a frequency greater than that of said subcarrier signal coupled to the output of said balanced modulator and said coding means output means.