| 6993153 |
Self-orienting watermarks |
| Jan-31-2006 |
A watermarking method converts a watermark message into a Frequency Shift Keying (FSK) signal and embeds the FSK signal in a host signal. The spectral properties of the FSK watermark signal facilitate... |
| 6973190 |
Method for protecting an electronic system with modular exponentiation-based cryptography against attacks by physical analysis |
| Dec-6-2005 |
The invention concerns a method for protecting an electronic system implementing a cryptographic calculation process involving a modular exponentiation of a quantity (x), said modular exponentiation using... |
| 6973188 |
Analog scrambler |
| Dec-6-2005 |
A method for scrambling/descrambling an analog signal includes receiving an analog signal and converting the signal into an intermediate frequency signal. A Gaussian pseudo-random noise signal is generated... |
| 6970843 |
Financial management system |
| Nov-29-2005 |
A financial transaction network includes a customer network serviced by a host processor. The financial transaction network provides customers with a plurality of diverse and interchangeable financial... |
| 6823455 |
Method for robust watermarking of content |
| Nov-23-2004 |
One inventive aspect pertains to a watermarking mechanism that allows a watermark to be determined from only a part of the video sequence without human intervention and without reference to the original... |
| 6731757 |
Multichannel digital signal generation method and apparatus |
| May-4-2004 |
A method of and apparatus for digitally generating a broadband signal comprising a plurality of CW or quadrature modulated signals having incrementally related frequencies wherein said plurality of signals... |
| 6625297 |
Self-orienting watermarks |
| Sep-23-2003 |
A watermarking method converts a watermark message into a Frequency Shift Keying (FSK) signal and embeds the FSK signal in a host signal. The spectral properties of the FSK watermark signal facilitate... |
| 6501841 |
Method for providing security for a transmission of information through a plurality of frequency orthogonal subchannels |
| Dec-31-2002 |
One embodiment of the present invention is a method for providing security for a transmission of information in an ADSL environment using a DMT modulation technique. The order of the frequency orthogonal... |
| 6389138 |
Method and apparatus for generating a complex scrambling code sequence |
| May-14-2002 |
A complex spreading and/or scrambling code sequence generation system uses a first complex code sequence having at least two components and a second complex code sequence having at least two components.... |
| 6345100 |
Robust watermark method and apparatus for digital signals |
| Feb-5-2002 |
Watermark data is encoded in a digitized signal by forming a noise threshold spectrum which represents a maximum amount of imperceptible noise, spread-spectrum chipping the noise threshold spectrum with... |
| 6229897 |
Apparatus and method of secured analog voice communication |
| May-8-2001 |
An apparatus and method for improved security in wire or wireless communication systems includes scrambling the audio signal, combining a masking signal with the scrambled audio signal, and then transmitting... |
| 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... |
| 5796838 |
Method and apparatus for performing frequency spectrum inversion |
| Aug-18-1998 |
An apparatus and method for creating voice privacy by performing frequency spectrum inversion in electronic voice transmission systems includes the steps of digitizing an analog signal and inverting the... |
| 5768374 |
Apparatus and method for continuous scrambling while transmitting or receiving synchronization data |
| Jun-16-1998 |
An apparatus and device for continuously scrambling audio while transmitting or receiving synchronization data. When transmitting, synchronization data will be substituted for scrambled audio but the audio... |
| 5757921 |
Radio communication apparatus having common oscillator applied for PLL, conversion and scramble/descramble circuits |
| May-26-1998 |
A superheterodyne receiving circuit and a superheterodyne transmitting circuit are provided. A PLL forms a local oscillation signal in the receiving circuit, and a PLL forms a carrier signal in the signal... |
| 5671284 |
Data encryptor having a scalable clock |
| Sep-23-1997 |
A method for encrypting and decrypting digital data. The digital data is initially latched by an input register. Sixteen separate cipher stages cascaded in series are used to encrypt the digital data.... |
| 5528692 |
Frequency inversion scrambler with integrated high-pass filter having autozero to remove internal DC offset |
| Jun-18-1996 |
A frequency inversion scrambler in a cordless telephone utilizes an integrated high-pass filter (14) between a first stage low-pass filter (12) and modulator (16) to reduce the filter order while maintaining... |
| 5471531 |
Method and apparatus for low cost audio scrambling and descrambling |
| Nov-28-1995 |
Audio signals are descrambled by double sideband modulating the scrambled audio signal with a modulation carrier having a carrier frequency slightly above the highest audio signal present in the scrambled... |
| 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... |
| 5392354 |
Cordless phone system capable of scrambling communication signals |
| Feb-21-1995 |
A cordless phone system includes a first cordless phone and a second cordless phone which are coupled to each other by a network, the first cordless phone being formed of a first personal station and a... |
| 5377223 |
Notch filtering a spread spectrum signal using fourier series coefficients |
| Dec-27-1994 |
A transmitter and receiver for spread spectrum communications using a Fourier series coefficients module, a notch gate, a fast Fourier transform module, and memory. The Fourier series coefficient module... |
| 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... |
| 5168522 |
Wireless telephone with frequency inversion scrambling |
| Dec-1-1992 |
The wireless telephone of the present invention is comprised of a base unit, coupled to a land-line telephone system, and a remote unit that communicates with the base unit over radio frequencies. The... |
| 5159631 |
Audio scrambling system using in-band carrier |
| Oct-27-1992 |
Audio signals are scrambled by single side band modulating with a modulation signal carrier having a frequency lying within the audio frequency band so that the signals are frequency translated upward.... |
| 5144666 |
Decoder to decode an encrypted sound |
| Sep-1-1992 |
Decoder for encrypted sound signals which are encrypted by modulating the sound signals on an alternating carrier signal having a frequency which is generally unknown to receiving parties. A modulator... |
| 5140635 |
Wireless telephone with frequency inversion scrambling |
| Aug-18-1992 |
The wireless telephone of the present invention is comprised of a base unit, coupled to a land-line telephone system, and a remote unit that communicates with the base unit over radio frequencies. The... |
| 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,... |
| 5058159 |
Method and system for scrambling and descrambling audio information signals |
| Oct-15-1991 |
Audio signals are scrambled by inverting the original; frequency spectrum so that frequency portions originally lying at the lower end of the audio frequency band are shifted to the upper end while those... |
| 5020104 |
Method of reducing the useful bandwidth of bandwidth-limited signals by coding and decoding the signals, and system to carry out the method |
| May-28-1991 |
The useful bandwidth of a bandwidth-limited input signal (s(t)) is reduced, to obtain a coded signal (q(t)) by forming a combined input and feedback signal, low-pass filtering the combined signal, and... |
| 5018198 |
Speech privacy processing method and apparatus therefor |
| May-21-1991 |
A speech privacy processing apparatus is disclosed including: a unit for obtaining the number of coefficients commonly included in a set of coefficients obtained by Fourier transformation and corresponding... |
| 4984219 |
Method and apparatus for decoding of frequency inversion based scramblers |
| Jan-8-1991 |
A method and apparatus for decoding of frequency inversion based scramblers is disclosed. A quadrature amplitude modulation detector determines the frequency of the tone used for inverting the scrambled... |
| 4969191 |
Fully digital phase-locked loop |
| Nov-6-1990 |
A fully digital phase-locked loop comprises a sampler (1), an analog-to-digital converter (2), two quadrature demodulators (3 and 4) and their associated filters (5 and 6), and a decision logic (7) effecting... |
| 4949378 |
Toy helmet for scrambled communications |
| Aug-14-1990 |
A toy helmet that permits the wearer to speak as to generate unintelligible noise so far as bystanders are concerned but which can be understood by another child wearing an identical helmet. Each helmet... |
| 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... |
| 4908860 |
System for the secret transmission of audio signals and television receiver for receiving such signals |
| Mar-13-1990 |
Encoding is realized by means of a first low-pass input filter (21), a first modulator (20), a second low-pass filter (19), a second modulator (18) whose modulating signal has a frequency which is pseudo-random... |
| 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... |
| 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... |
| 4817141 |
Confidential communication system |
| Mar-28-1989 |
The respective feature parameters extracted from a speech signal is converted into the corresponding line spectrum data in a first frequency band obtained by dividing the speech signal frequency band.... |
| 4802219 |
Method and apparatus for distorting a speech signal |
| Jan-31-1989 |
Method of distorting a speech signal by rearranging and/or reversing frequency bands in this signal. The speech signal is divided into a plurality of sub-bands by filtering, and the sub-bands are individually... |
| 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,... |
| 4773092 |
Speech scramblers |
| Sep-20-1988 |
A band scrambler which processes only time domain samples is described. The band scrambler has the effect of dividing the input signal spectrum into N sub-bands. The N sub-bands are permuted such that... |
| 4750205 |
Frequency or time domain speech scrambling technique and system which does not require any frame synchronization |
| Jun-7-1988 |
The present invention relates to speech scrambling techniques and systems and in particular to a frequency or time domain speech scrambling technique and system which does not require any frame synchronization.... |
| 4747137 |
Speech scrambler |
| May-24-1988 |
A speech scrambler is disclosed, in which a frequency spectrum obtained by an orthogonal transform of a time domain signal is divided into a plurality of blocks in the frequency domain. One of the blocks... |
| 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,... |
| 4659875 |
Electronic system for the secret transmission of audio signals |
| Apr-21-1987 |
System for the secret transmission of audio signals having at one end a coding arrangement comprising an input low-pass filter which selects the secret audio signals to be transmitted, two parallel signal... |
| 4612414 |
Secure voice transmission |
| Sep-16-1986 |
Voice signals are transmitted over a voiceband telephone channel with a high degree of security and good voice quality by applying to the transmission channel a first signal which includes digital information... |
| 4581765 |
Information security system |
| Apr-8-1986 |
A system is disclosed for encoding and decoding the audio signal portion of a television signal to prevent unauthorized reception of the audio signal. At the encoding stage, the audio signal is applied... |
| 4551580 |
Time-frequency scrambler |
| Nov-5-1985 |
Subband signals are formed each corresponding to a portion of an input signal frequency spectrum. The subband signals are partitioned into subband time segments. The subband time segment signals are permuted.... |
| 4525844 |
Method for interchanging n partial bands |
| Jun-25-1985 |
A method for interchanging the frequency positions of n partial bands, each having a bandwidth b, of a signal frequency band, by the steps of: sampling signals in the frequency band at an input sampling... |
| 4514852 |
Process for protected transmission of digital signals |
| Apr-30-1985 |
In order to achieve a higher resistance to interference with respect to alien sources of deliberate interference in the use of communication connections via short waves, certain cooperative measures are... |
