| 4972480 |
Holographic communications device and method |
| Nov-20-1990 |
A holographic device and method encrypts a time dependent data signal, s(t), by a complex time dependent phase shifting signal. This produces a new signal whose modulus is equal the absolute value of the... |
| 4972478 |
Soft logic cryptographic circuit |
| Nov-20-1990 |
A soft logic cryptographic circuit that can be reprogrammed with various cipher algorithms. The cryptographic circuit can be manufactured in a non-secure environment because a security sensitive cipher... |
| 4969160 |
Dual channel clock recovery circuit |
| Nov-6-1990 |
Apparatus is provided for detecting the presence of a periodically keyed random modulated signal source. Received signals are stepped down to an intermediate frequency and then applied to pairs of narrow... |
| 4964163 |
Method and apparatus for controlling access to a communication system |
| Oct-16-1990 |
Subscriber units operating within a communication system are selectively addressed and required to solve a "Puzzle" generated by a central device (controller) of a two-way communication system. The "Puzzle"... |
| 4962508 |
Dual channel interference canceller |
| Oct-9-1990 |
In a receiving apparatus for detecting the presence or absence of periodically keyed random modulated signals, there are provided a pair of separate and distinct detection channels. One channel produces... |
| 4949379 |
Process for encrypted information transmission |
| Aug-14-1990 |
A secure voice transmission system is disclosed in which enemy interception problems are overcome by analyzing the speech characteristics of a password from a known operator. Some of the voice characteristics... |
| 4947151 |
Wheel mounted motion and tampering alarm |
| Aug-7-1990 |
A tamper-proof motion and tampering alarm for a pneumatic tired vehicle consists of a motion detector, tampering detectors, radio transmitter, and power supply. All of these are mounted inside the pressurized... |
| 4924516 |
Method and system for a synchronized pseudo-random privacy modem |
| May-8-1990 |
A method and system for a synchronized pseudorandom privacy modem makes use of a pseudorandom signal generator to index into a table of N signal spaces thereby altering gain and phase modifiers so or to... |
| 4914696 |
Communications system with tandem scrambling devices |
| Apr-3-1990 |
An intermediate scrambling device for a radiotelephone system is disclosed by which it is possible to establish and maintain scrambled communications between an originating scrambler terminal and the most... |
| 4903298 |
System for providing encryption and decryption of voice and data transmissions to and from an aircraft |
| Feb-20-1990 |
A data communication system for an aircraft includes a voice encryption unit that is selectably included in the audio path between a user and a radio. The data communication system is interconnected so... |
| 4882751 |
Secure trunked communications system |
| Nov-21-1989 |
A trunked communications system that accommodates encrypted secure communications. The system uses both non-encrypted message detectors and encrypted message detectors to assure that the trunked central... |
| 4864612 |
Method of avoiding accidental actuation of maintenance equipment in a communications network |
| Sep-5-1989 |
A technique for avoiding accidental actuation of communications system devices which respond to a predetermined pattern of signals. In accordance with the present invention, data to be transmitted through... |
| 4860352 |
Satellite communication system and method with message authentication suitable for use in financial institutions |
| Aug-22-1989 |
A satellite communications system apparatus and method for authenticating data transmissions uses the position of the transmitter, which position is determined by the satellite communications system. The... |
| 4831438 |
Electronic surveillance system |
| May-16-1989 |
The present invention is a "tethered remote" surveillance system that uses a command and control transmitter/receiver to activate selectively a number of audio and video sensors. The system generally comprises... |
| 4815128 |
Gateway system and method for interconnecting telephone calls with a digital voice protected radio network |
| Mar-21-1989 |
A Gateway apparatus and method is disclosed which permits secure, end-to-end communications to exchange automatically between predetermined authorized subscribers operating on a radio network and a telephone... |
| 4811392 |
Communications network |
| Mar-7-1989 |
A transmitter station has a data source, a crypto unit, a buffer store for encrypted signals and a transmitter with an aerial, all with a common power supply. A switching control unit has a position in... |
| 4799257 |
Wireless transmission system for PM modulation signal |
| Jan-17-1989 |
A wireless transmitter for PM (phase modulation) signal with a spectrum scrambler for relocation of input spectrum for privacy purposes is comprised of a differential circuit coupled with an input terminal,... |
| 4727568 |
Unit for preventing an interception of a radio communication signal transmitted between a fixed facility and a mobile station |
| Feb-23-1988 |
In a radio frequency communication system in which a radio frequency communication signal is transmitted between a radio terminal (14) and a mobile station (24), it may be that an unauthorized third person... |
| 4726064 |
Wireless reception system |
| Feb-16-1988 |
A wireless receiver for a PM (phase modulation) signal with a spectrum scrambling for relocation of speech spectrums for the privacy of purpose is comprised of an antenna for receiving PM modulated signals,... |
| 4677552 |
International commodity trade exchange |
| Jun-30-1987 |
An International Commodity Trade Exchange having a central exchange post for providing international commodity information and a plurality of local exchanges in at least two countries around the world.... |
| 4652838 |
Phase randomization to reduce detectability of phase or frequency-modulated digital signals |
| Mar-24-1987 |
A communications system for conveying information angle-modulated onto a carrier includes a modulator which angle-modulates the data onto the carrier and which also randomly changes the phase of the carrier.... |
| 4623919 |
Method and system for controlling access to transmitted modulated electromagnetic wave carried information |
| Nov-18-1986 |
A method and system for making possible enforceable subscription available electromagnetically transmitted communications. Mailable receiver tuning components are described which serve to make receivers... |
| 4608455 |
Processing of encrypted voice signals |
| Aug-26-1986 |
The occurrence of a transmission error which produces a multibit error burst in the decrypted version of a composite speech and synchronization encrypted signal using a one-bit cipher feedback or similar... |
| 4595902 |
Anti-theft apparatus for vehicles |
| Jun-17-1986 |
In an anti-theft apparatus for vehicles with wireless transmission of the code signal, the latter is suitably overlapped outside of the vehicle by a secondary signal which is not to be received in or on... |
| 4573205 |
Technique for secure communications on FM radio channels |
| Feb-25-1986 |
This present invention relates to a system for providing secure communications without bandwidth expansion using an encryption method called masking whereby a masking signal is generated at the transmitter... |
| 4560832 |
Telephone system |
| Dec-24-1985 |
A cordless telephone system in which the incoming ring signals and audio signals transmitted from the base station to the remote station are digitized and encoded in accordance with a pseudo random code,... |
| 4555805 |
Secure mobile telephone system |
| Nov-26-1985 |
A communications system including a central station and a plurality of remote stations, for example, a mobile telephone system, is disclosed in which communications channel establishing signalling transmissions... |
| 4440976 |
Automatic selection of decryption key for multiple-key encryption systems |
| Apr-3-1984 |
A receiver of digitally encoded voice signals that may be encrypted according to a plurality of keep subjects a received signal to decryption according to each of the keys. Decrypted signals are tested... |
| 4411017 |
Secure mobile telephone system |
| Oct-18-1983 |
A communications system including a central station and a plurality of remote stations, for example, a mobile telephone system, is disclosed in which communications channel establishing signalling transmissions... |
| 4361729 |
Narrowband analog message privacy system |
| Nov-30-1982 |
A privacy system in which an analog information-bearing signal is linearly combined with a noiselike coding waveform to produce a composite waveform of unrecognizable, scrambled signal for transmission... |
| 4358857 |
Communication system |
| Nov-9-1982 |
1. In combination, a first source for producing a first signal representative of intelligence to be transmitted from one point to another, second source for producing a binary carrier signal having a first... |
| 4319087 |
Secret communication system |
| Mar-9-1982 |
This invention relates to a simplified pulse communication system for encrypting information to be transmitted over a communication link, which incorporates a novel randomizing and derandomizing procedure... |
| 4313207 |
Method and system for selectively disrupting radio telegraph communications |
| Jan-26-1982 |
A method and system for disrupting discrete keyed continuous wave radio communications wherein the discrete keyed continuous wave communications signal conveys intelligence by virtue of the duration and... |
| 4266095 |
Binary code randomizing system |
| May-5-1981 |
1. In a secret communication system including a source of an intelligence signal wave, means for periodically sampling said signal wave at predetermined intervals, and means for developing from the samples... |
| 4199809 |
Programmable data terminal set |
| Apr-22-1980 |
An operator console, a general purpose digital computer and a radio set irface are connected to perform the modulation and demodulation of the differential coherent quadrature phase shift signal used to... |
| 4167700 |
Digital voice protection system and method |
| Sep-11-1979 |
A digital voice privacy electronic communication system and method provides protection for an information signal. Either a clear voice signal or a scrambled digitized version of the voice signal is selected... |
| 4102521 |
System for signal coding |
| Jul-25-1978 |
1. In a system for the coding of guidance signals which are produced at a control center and after their coding transmitted to a body to be guided, a control center consisting of a command generator for... |
| 4077005 |
Secure position identity and time reporting system |
| Feb-28-1978 |
A system for identifying ships and aircraft, both in position and time, uizing shipboard cryptographic equipment and satellites is described. |
