According to the present invention, a radio apparatus has a section for receiving an analog signal and a digital angle-modulated carrier wave signal. The analog signal and digital angle-modulated carrier...
A security communication system comprises a transmission apparatus including a scrambling circuit for scrambling an information signal according to a specific code and a reception apparatus including a...
A signal scrambling system of the type in which the frequencies of the information signal band are inverted by heterodyning the information signal with a varying beat frequency. In accordance with the...
A receiver for detecting a double side-band noise like signal, in which the receiver is swept over a defined RF spectrum of interest, a phase inversion of the double side band signal is provided and multiplied...
A method and circuitry are disclosed in a telephone system for rendering an intelligible speech signal irreversibly unintelligible but recognizable as representing speech. Samples of an electrical speech...
A receiver for a carrier that is swept in frequency in a predetermined manner over a bandwidth comprises frequency tracking with continuous self-synchronization. The frequency tracking permits the carrier...
The known process for transmitting two or more audio signals over a single transmission channel by eliminating alternate small segments from a first signal and filling the gaps with alternate small segments...
1. In a secret telephone transmission system in which speech waves are analyzed into component speech-defining low frequency signals which are coded in stepped wave form, a group of frequency modulators...
The specification discloses a voice scrambler technique wherein a voice signal is split into a plurality of discrete frequency sub-bands. A random code genertor generates a randomized sequence of digital...
