Analog scrambling with continuous synchronization
AssigneeTranscrypt International, Inc.
InventorsKenneth L. Snyder, Ronald B. Kabler
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Abstract
A device and method for scrambling and de-scrambling audio and voice communications including radio, cellular telephone, and conventional telephone communication. The audio communication can be scrambled using, for example, time varying pseudo-random spectral modification. Continuous data containing synchronization information is transmitted with the scrambled signal to eliminate time lags that occur with synchronization bursts and without detrimentally affecting audio quality.
Claims46
A method of transmitting communications which are scrambled comprising:
- scrambling an audio signal that is used to modulate a transmission RF carrier;
- generating a continuous synchronization signal correlated to the scrambling of the audio signal;
- combining the synchronization signal with the audio signal;
- and
- so that the synchronization signal can be continuously transmitted with the audio signal to allow immediate initialization synchronization and continuous synchronization as long as the audio signal is transmitted.
An audio communication system comprising:
- at least one transmitter including an encoder;
- at least one receiver including a decoder;
- the encoder comprising an audio band scrambler;
- a sub-band generator which produces a frequency band which carries synchronization information on a continuous basis, and a combiner to combine the audible and sub-bands for transmission output;
- the decoder comprising a separator to separate the audio and sub-bands, a synchronization information recovery device to recover the synchronization information, and an audio recovery device which utilizes the synchronization information to recover the audio communication.
A method of audio communication comprising:
- scrambling an audio signal that is used to modulate a radio frequency signal;
- combining with the audio signal data modulated to a frequency sub-band within the audio signal.
Dependencies are inferred from the claim text.