Having Plural Band Pass Filters Patents (Class 380/40)
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Patent number: 9288045Abstract: A method for providing spectral and temporal stealthy information transmitted over an optical communication channel, according to which, at the transmitting side, the power spectral density of a pulse sequence bearing the information is reduced by encrypting the temporal phase of the pulse sequence. The power of the pulse sequence is spread in the frequency domain, to be below the noise level, by sampling the pulse sequence. Spectral phase encoding is used to temporally spread the pulse sequence and to prevent coherent addition of its spectral replicas in frequency domain. The resulting signal, encrypted both in time and frequency domains, is then transmitted. Spectral phase decoding is performed at the receiving side by performing coherent detection and folding all the spectral replicas of the transmitted signal to the baseband by means of sampling. The temporal phase of the signal is decrypted and the information which is delivered by the pulse sequence is decoded.Type: GrantFiled: July 17, 2012Date of Patent: March 15, 2016Assignees: Ben-Gurion University of the Negev Research and Development Authority, Bar-Ilan UniversityInventors: Dan Sadot, Zeev Zalevsky, Tomer Yeminy
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Patent number: 9036820Abstract: A system that incorporates the subject disclosure may include, for example, instructions which when executed cause a device processor to perform operations comprising sending a service request to a remote management server; receiving from the management server an authentication management function and an encryption key generator for execution by a secure element and an encryption engine for execution by a secure device processor, sending a request to establish a communication session with a remote device; and communicating with the remote device via a channel established using an application server. The secure element and the secure device processor authenticate each other using a mutual authentication keyset. The secure element, the secure device processor and the device processor each have a security level associated therewith; the security level associated with the secure device processor is intermediate between that of the secure element and that of the device processor. Other embodiments are disclosed.Type: GrantFiled: September 11, 2013Date of Patent: May 19, 2015Assignee: AT&T INTELLECTUAL PROPERTY I, LPInventors: Walter Cooper Chastain, Stephen Emille Chin
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Patent number: 8948379Abstract: The invention relates to a system for data exchange between at least two communication networks using the IP Internet protocol, a first network having a security level N1 higher than the security network N2 of a second network, and several terminals being connected to the first and second networks, characterised in that it comprises at least the following members: means for marking the flows based on their security level, a gateway between the first network (1) and the network (2) for carrying out a protocol interruption, and means for filtering the data flows suitable for checking the marking and to give authorisation for the broadcasting of the flow based on the relevancy between the marker and the sensitivity level of the communication, and visual means on the terminal for indicating to the user whether or not he communicates on a secured media.Type: GrantFiled: April 3, 2008Date of Patent: February 3, 2015Assignee: ThalesInventors: Francoise Maire, Michel Renaux, Frederika Baskaradasse, Michel Oustric
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Patent number: 8903091Abstract: A secure optical communication system and method are disclosed. Short optical pulses are first modulated with data, then dispersed in time so that they spread out over multiple bit periods, then the desired code is applied to the dispersed pulses. The encoding may include frequency shifts or phase shifts or other. The dispersed optical symbols overlap in time so an applied code chip thus acts on multiple symbols simultaneously. There are generally multiple code chips per dispersed symbol. The coding device does not need to be synchronized to the data rate. Multiple wavelength division multiplexed channels may be encoded simultaneously. The signal propagates to a decoder that is synchronized with encoder to apply a complementary code thereby canceling out the effect of the encoder. The encoder and decoder can be realized by varying the wavelength of an optical pump to a parametric amplifier, allowing for a wide-band frequency shift.Type: GrantFiled: September 22, 2011Date of Patent: December 2, 2014Assignee: Nucript LLCInventor: Gregory S. Kanter
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Patent number: 8886942Abstract: A method, non-transitory computer readable medium and apparatus for decrypting a document are disclosed. For example, the method captures a tag on an encrypted document, transmits the tag to an application server of a communication network to request a per-document decryption key, receives the per-document decryption key if the tag is authenticated, and decrypts a portion of the encrypted document using a temporary decryption key contained in the tag, the tag decrypted with the per-document decryption key.Type: GrantFiled: December 7, 2012Date of Patent: November 11, 2014Assignee: AT&T Intellectual Property I, L.P.Inventors: Andrea Forte, Evgene Vahlis
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Patent number: 8787569Abstract: Method to secure the communication of components within self-service automats that are linked to each other by a bus system, having a transmitter and a receiver, characterized in that data are exchanged as tuples (C, A, R, N, Z) on the transport layer of the bus system where C are the message data M encrypted with an encryption key, A are the message data M authenticated with an authentication key, R represents the role of a component on the bus system of active or passive participants, N represents a message counter, Z represents a session counter.Type: GrantFiled: October 22, 2009Date of Patent: July 22, 2014Assignee: Wincor Nixdorf International GmbHInventors: Volker Krummel, Michael Nolte, Matthias Runowski, Johannes Bloemer
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Publication number: 20140050316Abstract: The invention concerns the contact-less technology MIFARE, and describes a method to update a state by injecting an IV using a non-linear feedback shift register that makes use of only look-up tables and basic operations on 8-bit words.Type: ApplicationFiled: April 12, 2012Publication date: February 20, 2014Applicant: GEMALTO SAInventors: Aline Gouget, Pascal Paillier
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Patent number: 8601259Abstract: A sentinel value is combined with a data segment, and encrypted. A digest of the encrypted combined data segment is calculated, and used in conjunction with an encryption key to generate a masked key. This masked key is then appended to the encrypted combined data segment and transmitted to an encoder. When the data segment is retrieved, the original encryption key can be recovered and used to decrypt the data segment. The sentinel value can then be extracted from the data segment and checked for integrity. The data segment can then be delivered, discarded, flagged, or otherwise handled based on the integrity of the sentinel value.Type: GrantFiled: April 14, 2010Date of Patent: December 3, 2013Assignee: Cleversafe, Inc.Inventor: Jason K. Resch
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Patent number: 8582759Abstract: There is provided a method and apparatus for providing a content service. A method of providing a content service includes generating a plurality of pieces of decryption information according to a continuous period of using a broadcasting service with respect to predetermined contents, encrypting the contents, and decrypting the encrypted contents using the decryption information.Type: GrantFiled: July 13, 2011Date of Patent: November 12, 2013Assignee: Samsung Electronics Co., Ltd.Inventors: Hyoung-shick Kim, Myung-soo Chang
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Patent number: 8520843Abstract: In an inventive method for encrypting a discrete signal consisting of successive samples the successive samples are subdivided into successive time blocks, and the successive time blocks are then encoded into encoded data blocks having a predetermined order. Subsequently, the predetermined order of the encoded data blocks is altered in accordance with a predetermined interchange specification. The underlying findings are that a very high level of security of the encryption may be achieved by introducing temporal discontinuity, and that the occurrence of errors in unauthorized processing of signals encoded in such a manner maybe prevented, and the compatibility with standard codings may be ensured by performing the alteration of the chronological order in accordance with a coding of the discrete signal, i.e. with regard to encoded data blocks into which an encoder encodes the discrete signal.Type: GrantFiled: August 2, 2002Date of Patent: August 27, 2013Assignee: Fraunhofer-Gesellscaft zur Foerderung der Angewandten Forschung E.V.Inventors: Sascha Disch, Johannes Hilpert, Manfred Lutzky, Marc Gayer, Reinfried Bartholomaeus
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Patent number: 8503674Abstract: Cryptographic keys and, subsequently, the data they are intended to protect, are safeguarded from unwarranted attacks utilizing various systems and methodologies designed to minimize the time period in which meaningful versions of cryptographic keys exist in accessible memory, and therefore, are vulnerable. Cryptographic keys, and consequently the data they are intended to protect, can alternatively, or also, be protected from attackers utilizing systems and a methodology that employs a removable storage device for providing authentication factors used in the encryption and decryption processing. Cryptographic keys and protected data can alternatively, or also, be protected with a system and methodology that supports data separation on the storage device(s) of a computing device. Cryptographic keys and the data they are intended to protect can alternatively, or also, be protected employing a system and methodology of virtual compartmentalization that effectively segregates key management from protected data.Type: GrantFiled: April 28, 2011Date of Patent: August 6, 2013Assignee: Microsoft CorporationInventors: Octavian T. Ureche, Innokentiy Basmov, Grigory B. Lyakhovitskiy, Stefen Thom
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Patent number: 8478764Abstract: Content filtering of data containers of multiple content types is performed using multiple filtering modules operating concurrently. An apparatus for content filtering has a set of content-specific filtering modules and a network interface for parsing a received data container into components and directing each component to a respective filtering module. A filtering module edits a component of a specific content type according to respective rules. A multiplexer combines edited components produced by the set of filtering modules to form an edited data container. A root module applies a set of basic rules to a data container and any attachments. In an alternative configuration, the apparatus employs multiple filtering modules each applying rules for all content types. Received data containers are distributed among the filtering modules and an output module arranges edited data containers of a data stream in proper sequential order.Type: GrantFiled: August 26, 2010Date of Patent: July 2, 2013Assignee: Vantrix CorporationInventors: Richard Elliott Norton, Louis-Rene Poirier-Beuchemin, Robert Héroux, Mario Joseph Leo Claude Lavalliere
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Patent number: 8352374Abstract: Methods and systems for controlling the distribution of digital content are provided. A license holder acquires protected content and an original digital license to the protected content from a content provider system. The license holder in turn delegates all or part of the grants in that original license to other qualified devices or clients. The content remains in its original, protected or encrypted form while it is delivered from the license holder to the client along with a digital sublicense that the client receives from the original license holder, whereupon the content can then be rendered. The original digital license defines or governs the conditions under which such delegation occurs, and includes terms under which such delegation is permitted to continue in order to enforce the intent of the content provider.Type: GrantFiled: August 30, 2010Date of Patent: January 8, 2013Assignees: Sony Corporation, Sony Electronics Inc.Inventors: Eric John Swenson, Ryuji Ishiguro, Motohiko Nagano, Pierre Chavanne
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Patent number: 8280044Abstract: A stream encryption method encodes plaintext of N number of 1-bit input signal sequences into L (L is N or more) bits of encrypted text using N number of pseudo random sequences and uses only one pseudo random sequence used for the encryption to decode the single corresponding plaintext. This stream encryption method comprises using the N number of pseudo random sequences to divide a L-bit encryption symbol set averagely into two equal parts; selecting either of the two partial sets by a corresponding 1-bit plaintext sequence; and when there are one or more elements of the selected N number of partial sets forming common parts in the sets, using one of those as an encryption symbol.Type: GrantFiled: June 26, 2009Date of Patent: October 2, 2012Assignee: Fujitsu LimitedInventor: Motomu Takatsu
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Patent number: 8219821Abstract: A system and method for signature based data container recognition is provided. When a new data container, such as a lun, is created, a security appliance generates a signature of the data container, by, e.g., examining the contents of one or more data blocks of the data container. The generated signature is then associated with the appropriate encryption key for the data container and is stored either within a configuration database of the security appliance or on a key management system operating within a security appliance environment. To identify the encryption key associated with a data container, the security appliance generates a signature of the data container and compares the generated signature with the stored signatures. Should there be a matching signature, the security appliance utilizes the encryption key associated with the matching signature to process data access requests to/from the data container.Type: GrantFiled: March 27, 2007Date of Patent: July 10, 2012Assignee: NetApp, Inc.Inventors: Ori Zimmels, Yuval Frandzel
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Patent number: 8000472Abstract: The present invention stores and manages only one piece of key information even if contents information includes a plurality of partial contents arranged in a sequence, and the partial contents are encrypted with different keys. When a piece of contents information includes four partial contents or divided into four partial contents, a key for each of four node positions is generated through four steps of operations from a key for the top root. Node keys P (i, 1) and P (i, i) at both sides are generated by a one-way function from node keys P (i?1, 1) and P (i?1, i?1) at the upper i?1th layer, and a node key P (i, m) (m=2, 3, . . . , i?1) are generated by a one-way function which can generate the keys from any of node keys P (i?1, m?1) and P (i?1, m) at the upper i?1th layer, where jth node key at the ith layer is represented as P (i, j) (j=1, 2, . . . , i?1). Then, each of partial contents is encrypted with key information generated at a terminal layer.Type: GrantFiled: December 21, 2006Date of Patent: August 16, 2011Assignee: Canon Kabushiki KaishaInventor: Yuji Suga
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Patent number: 7949131Abstract: A system and method for processing a digital audio signal is disclosed. The system includes an input to receive a digital audio signal and a first output to provide a first digital output signal. The digital audio signal has a first fidelity characteristic and the first digital output signal has a second fidelity characteristic. The second fidelity characteristic is determined in response to security information extracted from the digital audio signal. The first digital output signal is provided to a digital to analog converter.Type: GrantFiled: December 19, 2005Date of Patent: May 24, 2011Assignee: Sigmatel, Inc.Inventors: Antonio Torrini, Konstantin Shkolnyy
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Patent number: 7760915Abstract: The invention provides a method, system, and program product for encrypting information. In one embodiment, the invention includes prompting a user for a password associated with a digital signature certificate stored in a digital pen, capturing a handwritten password made using the digital pen, displaying to the user the captured password, and encrypting information entered using the digital pen using the captured password. In some embodiments, the password may be captured from a predefined field on a digital page.Type: GrantFiled: October 9, 2006Date of Patent: July 20, 2010Assignee: International Business Machines CorporationInventors: Kulvir S. Bhogal, Gregory J. Boss, Rick A. Hamilton, II, Alexandre Polozoff
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Patent number: 7545929Abstract: The ability to securely transmit information between two locations is of paramount importance in today's communication systems. Before the invention of digital transmission methods, analog transmission was commonplace. However, today's communication systems rely almost exclusively on transmitting information digitally. Digital transmission has become commonplace because it provides optimal accuracy and security. However, digital transmission also has drawbacks, for example, increased bandwidth requirements and the loss of information when converting information between the analog and digital domains. The present invention relates to a method and apparatus for encrypting analog data while minimizing data loss and conserving bandwidth.Type: GrantFiled: October 25, 2002Date of Patent: June 9, 2009Assignee: Lockheed Martin CorporationInventors: Harold D. Babb, Michael J. Brooks
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Patent number: 7310421Abstract: An object is to enhance the difficulty in decrypting ciphertext. In order to do input into an encryption algorithm that receives plaintext to output ciphertext, a particular plaintext detector for detecting that the plaintext satisfying a predetermined condition is inputted, the particular plaintext detector includes: a receiving part for receiving the plaintext; a counter part for separating a predetermined part from a bit string forming the plaintext into a fixed part and a remaining part into a variable part, counting the inputted plaintext having a value of the fixed part included in a set of values of the fixed parts at every set of the values of the fixed parts formed of 1 or a plurality of the values of the fixed parts, and storing it as a separate count; and a detecting part for outputting a detection signal when at least one of the separate counts exceeds a predetermined number.Type: GrantFiled: October 6, 2003Date of Patent: December 18, 2007Assignee: National Institute of Information and Communications TechnologyInventors: Hidema Tanaka, Toshinobu Kaneko, Nobuyuki Sugio
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Patent number: 7277546Abstract: Methods and apparatus for converting original data into a plurality of sub-bands using wavelet decomposition; encrypting at least one of the sub-bands using a key to produce encrypted sub-band data; and transmitting the encrypted sub-band data to a recipient separately from the other sub-bands.Type: GrantFiled: April 9, 2004Date of Patent: October 2, 2007Assignee: New Jersey Institute of TechnologyInventor: Atam P. Dhawan
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Patent number: 7236595Abstract: The present invention relates generally to an integrated optics encryption device. The preferred embodiment of the invention is an integrated optics encryption device comprising a coherent light source connected to a multi-functional integrated optics chip (MIOC). The MIOC comprises two divergent paths with mirrored ends. The MIOC also has an encrypted message output. One path is connected to a message signal input that can alter the refractive index of the path. The other path is connected to a key signal input that can alter the refractive index of the other path.Type: GrantFiled: April 18, 2000Date of Patent: June 26, 2007Assignee: Litton Systems, Inc.Inventors: Michael L. Bean, Lawrence E. Bean, George A. Pavlath, Eric Lee Goldner
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Patent number: 7006634Abstract: A system for the encryption and decryption of data employing dual ported RAM for key storage to accelerate data processing operations. The on-chip key storage includes a dual-ported memory device which allows keys to be loaded into memory simultaneous with keys being read out of memory. Thus, an encryption or decryption algorithm can proceed while keys are being loaded into memory.Type: GrantFiled: September 28, 2000Date of Patent: February 28, 2006Assignee: Cisco Technology, Inc.Inventor: Kenneth W. Batcher
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Patent number: 6898288Abstract: A method for secure transmission of a data message locks, at the sender, the data message using a first lock. The locked data message is transmitted to the receiver. Next, the locked data message is double-locked, at the receiver, using a second lock. Then, this double-locked data message is transmitted back to the sender. The first lock of the double-locked data message is then unlocked, at the sender, using a first key, leaving the data message single-locked by the second lock. The single-locked data message is transmitted back to the receiver, where the second lock of the single-locked data message is unlocked, using a second key, to generate the data message, completing the secure transmission.Type: GrantFiled: May 23, 2002Date of Patent: May 24, 2005Assignee: Telesecura CorporationInventor: Charles K. Chui
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Publication number: 20030023986Abstract: In a recording system for digital broadcasting are provided a log data generation unit for generating log data (a log) based on information about TS packets outputted from a packet separation unit, a data filter unit and a data search unit. The log is comprised of, for example, the first to fourth 4-byte words. The log is generated with respect to each TS packet that has passed through the packet separation unit and temporarily stored in a register within the log data generation unit. Thereafter, when the content of the stored log satisfies previously determined conditions, the log data generation unit outputs the log to a memory access unit (control unit).Type: ApplicationFiled: June 28, 2002Publication date: January 30, 2003Applicant: NEC CORPORATIONInventor: Hiroshi Honmura
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Publication number: 20020080957Abstract: A method of concealing errors in a single bit bitstream comprises low pass filtering the bitstream, replacing the low pass filtered signal during an error by a low frequency approximation of the signal and subsequently converting the signal by a &Sgr;&Dgr;-modulator into a regenerated single bit bitstream. During the absence of an error the original bitstream may be outputted and during an error the regenerated bitstream, which is obtained from a &Sgr;&Dgr;-modulator, which is bit-synchronized to the original bitstream.Type: ApplicationFiled: August 9, 2001Publication date: June 27, 2002Inventors: Derk Reefman, Alphons Antonius Maria Lambertus Bruekers
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Patent number: 6175639Abstract: A digital data encode system for inserting water mark data into digital data signals having a series of field data by use of a water mark data inserting device, the digital data encode system has a field judging unit dividing the digital data signals by a predetermined reference, a water mark data selection output unit for selecting proper one of a plurality of different water mark data prepared correspondingly to the division according to the judgment result of the field judging unit, and a water mark data inserting device for inserting the water mark data supplied from the water mark data selection output unit into the digital data signals.Type: GrantFiled: February 24, 1998Date of Patent: January 16, 2001Assignee: NEC CorporationInventors: Shinobu Satoh, Yutaka Wakasu
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Patent number: 5995629Abstract: An encoding device includes an encoding unit and an output register downstream of the encoding unit. During a second time period, encoded output data are formed from input data fed to the encoding unit and are written into the output register. After the second time period elapses, no further data are fed to the output register, but power consumption of the output register must not alter. The encoding unit continues to generate output data until a first time period elapses. The encoding device prevents an external observer from drawing any conclusions from the power consumption of the encoding device as to the actual generating period of the encoded output data in the output register.Type: GrantFiled: August 15, 1997Date of Patent: November 30, 1999Assignee: Siemens AktiengesellschaftInventor: Robert Reiner
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Patent number: 5991416Abstract: A scrambling and a descrambling circuit for cordless telephone provides a higher security level than current phone scrambling circuitry. The higher security level is accomplished by separating an audio signal into low and high frequency bands. The frequency bands are selectively inverted or non-inverted during scrambling and descrambling according to common selection conditions. The processed signals are mixed into an overall mixed signal. The overall mixed signal is selectively inverted or non-inverted during scrambling and descrambling according to a common selection condition to increase the phone's transmission security level.Type: GrantFiled: October 21, 1996Date of Patent: November 23, 1999Assignee: Samsung Electronics, Co. Ltd.Inventor: Yl-Sung Bae
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Patent number: 5778073Abstract: A digitized real voice signal is converted via complex filtering into a complex signal that is subjected to sampling rate reduction, the bandwidth of the respective complex filter corresponding to the sampling rate. The complex signal is phase-modulated by means of a code signal generated by a random-number generator and additively combined with a pilot signal (likewise phase-modulated in a random distribution) to form an encrypted useful signal for transmission. The useful signal is sequentially transmitted together with a preamble for synchronization and signal equalization at the receiver end. At the receiver end, clock synchronization is forced for a phase-modulated pilot signal produced at the receiver end and equalizer coefficients for an equalizer at the receiver end are calculated from the digitized received signal after complex filtering and corresponding sampling rate reduction, during a preamble recognition phase, at which point the phase of the useful signal decryption is initialized.Type: GrantFiled: May 14, 1996Date of Patent: July 7, 1998Assignee: Litef, GmbHInventors: Wolfram Busching, Erhard Schlenker, Gunter Spahlinger
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Patent number: 5528692Abstract: 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 low group delay in the audio signal. The first stage low-pass filter and high-pass filter remove high frequency components and any DC offset from the filtered audio signal. The modulator translates the spectrum of the filtered signal to sum and difference frequencies. A second stage low-pass filter (18) removes the upper portion of the spectrum such that the resulting frequency spectrum is inverted with respect to the original audio signal to prevent eavesdropping of transmissions between the handset and base unit of the cordless telephone. Another frequency inversion circuit (30, 32, 34, 36) in the base unit inverts the frequency spectrum again back to its original state for transmission along telephone lines.Type: GrantFiled: May 3, 1994Date of Patent: June 18, 1996Assignee: Motorola, Inc.Inventors: Richard E. Hester, Scott K. Bader
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Patent number: 5471531Abstract: 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 audio. This produces a double sideband signal that is passed through a low pass filter which in turn is modulated by a second carrier frequency lower than the first carrier signal by an amount equal to the offset spectrum of the original scrambled signal. The first low pass filter nulls out any residual carrier from the first modulator that results from the of intermodulation of the two modulation frequencies that would be audible at its descrambler output. The modulators used are low noise switch type modulators that improve the signal to noise ratio in the descrambled signal over the previously used linear modulators. The use of switch type modulators provides a lower cost device with improved performance.Type: GrantFiled: December 14, 1993Date of Patent: November 28, 1995Assignee: Macrovision CorporationInventor: Ronald Quan
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Patent number: 5446795Abstract: A universal decoder for scrambled television signals in which the signals are processed in a circuit by converting them to other frequencies and then removing the scrambling signal. One method uses one or more narrow filters at a fixed frequency with the television signal being heterodyned down to the frequency of the filters to place the scrambling signals in the rejection band of one of the filters. A second method eliminates scrambling signals by filters at video frequencies. In this method, the frequency in phase with the television signal carrier of a television channel is regenerated by filtering it with a narrow crystal filter and by means of an automatic phase comparison (APC) loop. The regenerated carrier is then used to synchronously demodulate the television signal. A third method for removing the scrambling signals is by use of one or more comb filters.Type: GrantFiled: March 25, 1993Date of Patent: August 29, 1995Assignee: International Telesystems, Inc.Inventors: Adrian J. Devries, Bruno A. Rist
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Patent number: 5235640Abstract: A master decoder for scrambled television signals in which the signals are processed in a circuit by converting them to other frequencies and then removing the scrambling signal. One method uses one or more narrow filters at a fixed frequency with the television signal being heterodyned down to the frequency of the filters to place the scrambling signals in the rejection band of one of the filters. A second method eliminates scrambling signals by filters at video frequencies. In this method, the frequency in phase with the television signal carrier of a television channel is regenerated by filtering it with a narrow crystal filter and by means of an automatic phase comparison (APC) loop. The regenerated carrier is then used to synchronously demodulate the television signal. A third method for removing the scrambling signals is by use of one or more comb filters.Type: GrantFiled: December 21, 1989Date of Patent: August 10, 1993Assignee: International Telesystems, Inc.Inventors: Adrian J. Devries, Bruno A. Rist
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Patent number: 5018198Abstract: 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 to high-frequency spectrum components of an input original speech signal and the set of coefficients corresponding to the high-frequency spectrum components after scrambling processing;scrambler for repetitively performing scrambling processing until the number of the common coefficients becomes smaller than a predetermined threshold value;a counter for counting the number of repetitions of the scrambling processing and transmitting the count to a receiver side;a unit for extracting a repetition count of scrambling processing from a reception signal;descrambler for performing descrambling processing in accordance with the extracted repetition count; anda unit for reproducing a speech signal.Type: GrantFiled: January 18, 1990Date of Patent: May 21, 1991Assignee: Canon Kabushiki KaishaInventor: Futoshi Takahashi
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Patent number: 5008937Abstract: In a scrambled-communication system, a transmitting station generates a scrambling noise having a periodically-recurrent series of noise patterns and scrambles an information signal by simply summing the scrambling noise to the information signal, whereby the information signal is totally unintelligible by an interceptor. At a receiving station, a noise-cancelling signal is generated by an adaptive transversal filter and supplied to a subtractor where it is combined with the scrambled signal to recover the information signal. For generating the noise-cancelling signal, a descrambling noise identical to the scrambling noise is generated. The filter has a tapped-delay line for receiving the descrambling noise and a plurality of variable tap weights connected respectively to taps of the tapped-delay line.Type: GrantFiled: June 26, 1989Date of Patent: April 16, 1991Assignee: NEC CorporationInventors: Yoshihiro Yamamura, Takashi Ogihara, Yoshinobu Nakanishi, Tomohiro Nishizono
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Patent number: 4949378Abstract: 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 is equipped with internal and external microphones and an external speaker and internal earphones. Scrambler/descrambler circuitry is selectively connectable by means of a push-to-talk switch that delivers speech from the internal microphone to the external loudspeaker of the first helmet. The external microphone and the corresponding scambler/descrambler circuitry and push-to-talk switch of the second helmet delivers unscrambled speech to its internal earphone to permit the two helmet wearers to communicate intelligibly with one another. The scrambler/descrambler circuitry samples the low-pass filtered signals applied to its microphones at a sampling rate equal to the cut-off frequency of the low-pass filter.Type: GrantFiled: February 21, 1990Date of Patent: August 14, 1990Inventor: Richard J. Mammone
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Patent number: 4852166Abstract: 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) into N sub-band signals sampled at f.sub.e /N and transferred in a permuted order to a synthesis filter bank (13) accomplishing the calculations of the scrambled signal sampled at the rate f.sub.e. A set of permutations is protected in a memory (8) and a scrambling with dynamic permutation in time is obtained by changing the read addresses of the memory. The scrambled signal reconverted into an analogue signal (14, 15) is transmitted through an analogue channel to an unscrambler where it is preprocessed so that the synchronizing and equalizing functions are accomplished and where the accomplished processes are identical with those accomplished in the scrambler, the difference being that the permuted order of the N sub-band signals is restored.Type: GrantFiled: October 30, 1987Date of Patent: July 25, 1989Assignee: Telecommunications Radioelectriques et Telephoniques T.R.T.Inventor: Jacques L. R. Masson