| 6996237 |
Apparatus and methods for including codes in audio signals |
| Feb-7-2006 |
Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code... |
| 6961431 |
Analog privacy scrambler and scrambling method |
| Nov-1-2005 |
A system and method for maintaining privacy in transmission of a high bandwidth analog signal. A preferred system and method breaks an input signal into bands and then uses Walsh codes to overlay many... |
| 6907123 |
Secure voice communication system |
| Jun-14-2005 |
A secure real time voice communication system 70 is provided that allows for the secure transmission of voice communications between a sending device 72 and a receiving device 78 through the public switch... |
| 6658112 |
Voice decoder and method for detecting channel errors using spectral energy evolution |
| Dec-2-2003 |
A voice decoder detects channel errors and loss of cryptographic synchronization using the change in spectral energy between sequential frames. The change in energy between frames is determined between... |
| 6421445 |
Apparatus and methods for including codes in audio signals |
| Jul-16-2002 |
Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code... |
| 6356638 |
Radio wireline interface and method for secure communication |
| Mar-12-2002 |
An interface between a digital communication system and a PSTN establishes a user configurable secure encrypted link to a digital subscriber unit through the digital communication system, and provides... |
| 6339646 |
Slotted mode code usage in a cellular communications system |
| Jan-15-2002 |
The downlink channelization code limitation problem encountered in spread spectrum or CDMA cellular systems is resolved by using codes from a different, non-orthogonal code set when operating in the slotted... |
| 6272633 |
Methods and apparatus for transmitting, receiving, and processing secure voice over internet protocol |
| Aug-7-2001 |
This disclosure describes systems and methods for processing voice data for secure transmission and secure receipt over a network, such as the Internet. The systems and methods include the processing of... |
| 6266418 |
Encryption and authentication methods and apparatus for securing telephone communications |
| Jul-24-2001 |
An encryption device for a telephone having a handset and a base unit is disclosed. The device includes a handset interface, a first converter, an encryption processor, a second converter, and a host interface.... |
| 6266412 |
Encrypting speech coder |
| Jul-24-2001 |
Disclosed is an encrypting speech processor architecture that provides enhanced security without the use of external cryptosync and with minimal speech degradation. This is accomplished by incorporating... |
| 6260143 |
Host-based caching method and system for copy protected content |
| Jul-10-2001 |
A method and system of read-ahead caching for use in a DVD player utilizing CSS titles is disclosed. The caching system is a host-based read-ahead caching system that utilizes a threaded architecture for... |
| 6256491 |
Voice security between a composite channel telephone communications link and a telephone |
| Jul-3-2001 |
An apparatus and method for security of individual communications over a composite communications channel such as T1 or E1. The composite channel is digitized. Individual channels are separated, but identifying... |
| 6078668 |
Apparatus and method for concealing data bursts in an analog scrambler using audio repetition |
| Jun-20-2000 |
An apparatus and method for concealing data bursts in an analog scrambler using audio repetition. What otherwise would be periodic data bursts appearing at the audio output are replaced with samples from... |
| 5852662 |
Scrambler bypass system |
| Dec-22-1998 |
A cordless phone configured to operate in both a scrambling mode and non-scrambling mode comprises a base station and a cordless handset terminal. Both the base station and the cordless handset terminal... |
| 5784422 |
Apparatus and method for accurate synchronization with inbound data packets at relatively low sampling rates |
| Jul-21-1998 |
An apparatus and method for accurate synchronization with inbound audio data which packets at relatively low sampling rates. By using previously known information such as the time of arrival of the beginning... |
| 5764763 |
Apparatus and methods for including codes in audio signals and decoding |
| Jun-9-1998 |
Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code... |
| 5742679 |
Optimized simultaneous audio and data transmission using QADM with phase randomization |
| Apr-21-1998 |
An subsystem processor for converting an input audio signal to complex audio samples for QADM processing by a modem for communication with a remote modem is disclosed. The audio process comprises a decorrelator... |
| 5710813 |
Digital voice recording/reproducing apparatus |
| Jan-20-1998 |
A digital voice recording/reproducing apparatus comprises a user identification code memory, provided in a main body, for storing a predetermined user identification code in advance before the apparatus... |
| 5621800 |
Integrated circuit that performs multiple communication tasks |
| Apr-15-1997 |
An integrated circuit that provides multiple communication functions is accomplished by providing an integrated circuit (24) that includes memory (70) which stores an audio code algorithm, echo cancellation... |
| 5617476 |
Audio scrambling system for scrambling and descrambling audio signals |
| Apr-1-1997 |
A scrambling system has a scrambling apparatus and a descrambling apparatus for scrambling and descrambling a digital audio signal having a plurality of 16-bit long sample data units. The scrambling apparatus... |
| 5541997 |
Method and apparatus for detecting correctly decrypted communications |
| Jul-30-1996 |
In a receiver (100), an encrypted communication (104) is decrypted using a decryptor (101) and a key (107) to produce a decrypted communication (105). A comparator (103) compares decrypted symbol patterns... |
| 5528693 |
Method and apparatus for voice encryption in a communications system |
| Jun-18-1996 |
A world-wide cellular radio telecommunications system utilizing low-earth orbit satellites provides secure transmissions of voice and data even though the length of the signal path of the communications... |
| 5450490 |
Apparatus and methods for including codes in audio signals and decoding |
| Sep-12-1995 |
Apparatus and methods for including a code having at least one code frequency component in an audio signal are provided. The abilities of various frequency components in the audio signal to mask the code... |
| 5400404 |
Modulation/demodulation circuit and communication system utilizing the same |
| Mar-21-1995 |
The present invention provides a modulation/ demodulation circuit and a communication system utilizing the modulation/demodulation circuit. The modulation/ demodulation circuit can be operated in either... |
| 5365590 |
System for providing access to digitally encoded communications in a distributed switching network |
| Nov-15-1994 |
A distributed switching network (switch) routes audio and control signals throughout the switch from various audio sources to one or more audio destinations. Audio sources such as mobile/portable radio... |
| 5335279 |
Digital voice-band spectrum inversion apparatus |
| Aug-2-1994 |
A digital speech-band spectrum inversion apparatus for use in a cordless telephone system provides transmission security of the voice signal between the handset (10) and the base station (18). The apparatus... |
| 5278907 |
Analog scrambling with continuous synchronization |
| Jan-11-1994 |
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... |
| 5197098 |
Secure conferencing system |
| Mar-23-1993 |
An audio system for conducting confidential multi-person conferences without the need for secure meeting facilities. Means for silently accepting spoken speech from a number of participants and making... |
| 5148482 |
Layered session data unit frame |
| Sep-15-1992 |
A layered session data unit frame (300) is provided wherein a first frame (200), designated a session data unit("SDU"), containing user information (209), a link control field (205) and an encryption field... |
| 5148478 |
System and method for communications security protection |
| Sep-15-1992 |
A system and method are disclosed for preventing intelligible interception of information signals transmitted over a two-direction line. A masking signal is applied through a hybrid circuit at the receiving... |
| 5091941 |
Secure voice data transmission system |
| Feb-25-1992 |
In the secure radio transmission system of the present invention the sign bit for each byte of audio digital data is scrambled to generate a scrambled sign bit. By altering the sign bit, the resultant... |
| 5065430 |
Voice band splitting scrambler |
| Nov-12-1991 |
Disclosed is a voice band splitting scrambler. To simplify the hardware thereof, the apparatus comprises a band splitting unit (11) for splitting an input voice signal into a plurality of band channels,... |
| 4981371 |
Integrated I/O interface for communication terminal |
| Jan-1-1991 |
An integrated I/O interface for a communication terminal, connectable with an external analog communication device and with an external digital communication device, includes an I/O interface subsystem... |
| 4964165 |
Method for the fast synchronization of vocoders coupled to one another by enciphering |
| Oct-16-1990 |
A method for the fast synchronization of vocoders, coupled to each other by means of enciphering and deciphering devices, consists in synchronizing the data frames transmitted by the vocoders with the... |
| 4959863 |
Secret speech equipment |
| Sep-25-1990 |
Disclosed is a secret speech equipment for ensuring the secrecy of an analog voice signal, and used in voice communication systems such as an analog telephone and mobile radio. The equipment comprises... |
| 4937867 |
Variable time inversion algorithm controlled system for multi-level speech security |
| Jun-26-1990 |
A method for scrambling speech such as in a mobile land based communication system is disclosed. Essentially, variable length time samples of digitized speech are stored and time inversion scrambled. The... |
| 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... |
| 4888799 |
Scrambling of signals by inversion |
| Dec-19-1989 |
The present invention is directed to an inversion scrambler and unscrambler having pseudo-randomly controlled polarity-reversing switches to invert and re-invert, respectively, an audio signal so as to... |
| 4873721 |
Device for starting charging in a pay phone |
| Oct-10-1989 |
The present invention relates to a device for starting telephone charging in a pay phone. The starting device essentially comprises a scrambler circuit (42) which is inserted in the line (26) when the... |
| 4852166 |
Analogue scrambling system with dynamic band permutation |
| Jul-25-1989 |
An analogue scrambling system with dynamic band permutation in which the speech signal is filtered (1), sampled (2) at the rate f.sub.e, digitized (3), transformed by means of an analysis filter bank (4)... |
| 4827507 |
Duplex analog scrambler |
| May-2-1989 |
An analog frequency inversion scrambler employing an exchange of random number seeds between an originating scrambler and an answering scrambler to create two pseudo-random frequency hopping rolling codes... |
| 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,... |
| 4790009 |
Scrambler system |
| Dec-6-1988 |
A scrambler system comprises in a transmitter part thereof as oscillator circuit for generating a local oscillation signal, a frequency dividing circuit for obtaining a frequency divided signal by frequency-dividing... |
| 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,... |
| 4683586 |
Scrambling system for an audio frequency signal |
| Jul-28-1987 |
A scrambling system for an audio frequency signal is disclosed which employs a timebase-compressing and/or expanding system to measure the compressed and/or expanded amount of a segment time length caused... |
| 4623980 |
Method of processing electrical signals by means of Fourier transformations |
| Nov-18-1986 |
In order to upgrade input signals for further processing, one or more of the input signals is split up by a decimating technique into spectral component signals which are processed according to the desired... |
| 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... |
| 4600941 |
Scrambling system for audio frequency signals |
| Jul-15-1986 |
A scrambling system for an audio frequency signal in which an audio signal is divided into blocks, each block being formed of a plurality of frames, the plurality of frames are rearranged on a timebase... |
| 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... |
| 4393276 |
Fourier masking analog signal secure communication system |
| Jul-12-1983 |
The present invention relates to a secure communication system for analog signals which preserves the bandwidth of the original message signal by employing scrambling, or masking, techniques in the frequency... |
