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| Number | Title | Issue Date |
| 7728691 | Modulator for radio-frequency signals A modulator for radio-frequency signals designed an entirely digital modulator has two mixer stages connected in series. The first mixer stage implements with a relatively low first sample rate a frequency mixing with a first oscillator frequency that is adjustable ... | 06/01/2010 |
| 7336721 | Digital frequency modulator A digital frequency modulator is disclosed. In the digital frequency modulator, a first gain controller multiplies an input digital signal by a first gain determined according to a required modulation frequency, a phase accumulator accumulates the input digital sign... | 02/26/2008 |
| 7319763 | Power amplification for parametric loudspeakers A power amplifier for a parametric loudspeaker system which utilizes switch-mode power conversion to increase efficiency. The power amplifier is configured to coordinate the switching frequency of the amplifier with the carrier frequency of the parametric loudspeake... | 01/15/2008 |
| 7295628 | Stereo multiplex encoder (MPX) for FM transmission A stereo multiplex encoder (MPX) for FM transmission with a digital signal processor utilizes residual sideband modulation in stereo transmission instead of the conventional double sideband modulation. The adjustment of the sampling frequency to the modulation frequ... | 11/13/2007 |
| 7227482 | Complex band-pass filter for use in digital radio receiver and complex band-pass Δ-Σ AD modulator using the same In a first-order complex band-pass filter, multiplexers are alternately switched over between time intervals of phases A and B, where the multiplexers includes two multiplexers provided at input and output stages, and a multiplexer provided in a feedback circuit of ... | 06/05/2007 |
| 7218898 | Apparatus and method for frequency generation in mobile communication system An apparatus and method for generating an intermediate frequency (IF) to be transferred to a single sideband (SSB) generator which generates carriers using one local oscillator (LO) signal and at least two IF signals that are received. A group signal is generated wh... | 05/15/2007 |
| 7184724 | System and method for frequency translation using an image reject mixer Frequency translation, such as frequency up conversion of a video baseband or intermediate frequency to a desired frequency division broadcast channel, is provided utilizing a single sideband or image reject mixer and filtering having relaxed selectivity requirement... | 02/27/2007 |
| 7167698 | Balanced sub-harmonic mixer A wide band mixer is provided that mitigates local oscillator leakage. A LO signal is provided to a 180 degree splitter that provides a first intermediate LO signal and a second intermediate LO signal 180° out of phase from one another. Since both the first and sec... | 01/23/2007 |
| 7167528 | Modulation system for modulating data onto a carrier signal with offsets to compensate for doppler effect and allow a frequency synthesizing system to make steps equal to channel bandwidth A method and system for modulating data onto a carrier signal in a plurality of channels, each of the channels having a channel bandwidth, can be created for use in any two-way satellite communication system or other wireless communication application where frequenc... | 01/23/2007 |
| 7116963 | Simplified high frequency tuner and tuning method A disclosed method tunes a signal from a channelized spectrum having a predetermined channel spacing. A signal of interest having a predetermined maximum bandwidth is mixed with a local oscillator signal, which has a frequency that is an integer multiple of the chan... | 10/03/2006 |
| 7113557 | Noise canceling method and apparatus A canceling method and apparatus can achieve a fast communication by improving an S/N value by adaptively canceling a noise with respect to a frequency or band having a large noise by selecting noise canceling band in accordance with a condition of noise being gener... | 09/26/2006 |
| 7065154 | Baseband predistortion method for multicarrier transmitters A multicarrier transmitter is shown having an embodiment of the invention. Sampling of modulated and amplified signals is done to obtain energy values for four or more symbols. Combining the energy values with the baseband in-phase and quadrature signals of the mult... | 06/20/2006 |
| 7057426 | Frequency converter, orthogonal demodulator and orthogonal modulator A frequency converter comprising a variable gain amplifier which amplifies the local oscillation signal according to a gain control signal and outputs an amplified local signal, an even harmonic mixer which is supplied with an input signal and an amplified local osc... | 06/06/2006 |
| 7042959 | DSP-based variable aperture code generation technique Variable Aperture Coded (VAC) signals for VAC modulation are advantageously generated by a digital signal processor (12) that yields a VAC signal having a single narrow peak in the positive frequency region. A Discrete-Time Hilbert transformer (12) iso... | 05/09/2006 |
| 7039372 | Method and system for frequency up-conversion with modulation embodiments A method and system is described wherein an information signals is gated at a frequency that is a sub-harmonic of the frequency of the desired output signal. In the modulation embodiments, the information signal is modulated as part of the up-conversion process. In ... | 05/02/2006 |
| 7006162 | Tuner An analogue single conversion tuner comprises a plurality of channels (1, 2, 3) for covering the whole of a desired reception bandwidth. Each tuner comprises an image reject mixer (18) connected to the tuner input (4) by a single tracking filter... | 02/28/2006 |
| 7006814 | Direct conversion receiver and transceiver A receiver of the direct conversion system by which problems arising from interference between a reception signal and a local signal used by a quadrature demodulator on the reception side are moderated. Where the carrier frequency of a transmission signal is represe... | 02/28/2006 |
| 6993084 | Coarse frequency synchronisation in multicarrier systems A method for generating a signal having a frame structure, each frame of the frame structure comprising at least one useful symbol, a guard interval associated to the at least one useful symbol and a reference symbol, comprises the steps of performing an amplitude m... | 01/31/2006 |
| 6993086 | High performance short-wave broadcasting transmitter optimized for digital broadcasting A short wave high efficiency radio broadcasting transmitter for digital transmissions. The transmitter includes a power tube in which the grid is excited by a variable phase signal through an excitation device and in which the anode is amplitude modulated by the out... | 01/31/2006 |
| 6952572 | Image rejection mixer with switchable high or low side injection An image rejection mixer includes first and second mixers, a phase shift circuit and a summer. The first mixer receives an RF input signal and a first local oscillator (LO) signal and generates a first intermediate frequency (IF) output signal. The second mixer rece... | 10/04/2005 |
| 6930627 | Radio-frequency digital/analog converter system and method A radio frequency (RF) converter system and associated method are provided for generating and/or receiving RF signals. Included is a signal conversion circuit for digital signal processing (DSP) or converting between digital signals and analog signals. Further provi... | 08/16/2005 |
| 6850575 | Single side band modulator The present invention relates to a single side band modulator for splitting a signal into a first split signal and a second split signal 90 degrees out of phase with the first split signal. A first double balanced mixer modulates the first split signal and includes ... | 02/01/2005 |
| 6731757 | Multichannel digital signal generation method and apparatus 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 are centered about a center RF frequency is disclosed. The i... | 05/04/2004 |
| 6720839 | System of and method for reducing or eliminating the unwanted sideband in a signal derived from the output of a quadrature modulator A system of and method for reducing or eliminating any unwanted sideband component in a signal derived from the output of a quadrature modulator. An unwanted sideband detector detects the unwanted sideband in the output of the quadrature modulator, and responsive th... | 04/13/2004 |
| 6647074 | Removal of clock related artifacts from an offset QAM generated VSB signal Circuits for removing clock related artifacts in an offset QAM generated VSB signal includes a transmitter arrangement and a receiver arrangement. In the transmitter, a detector detects the artifacts and a correlator determines whether the artifacts repea... | 11/11/2003 |
| 6618096 | System and method for adaptively balancing quadrature modulators for vestigial-sideband generation A digital signal processing vestigial-sideband television modulator receives a television signal. The present invention digitizes the television signal to generate a video signal and a digital processor processes the video signal to generate a complex bas... | 09/09/2003 |
| 6606010 | Quadrature vestigial sideband digital communications method A quadrature vestigial sideband (QVSB) communication system provide bandwidth efficient data transmission using cross coupled data signaling during both transmit and receive having controlled intersymbol interference. The QVSB modem includes cross coupled... | 08/12/2003 |
| 6567394 | Non-contact IC card and system for performing data communication An IC card, an IC card processor, and an IC card system are simply arranged to perform full-duplex data exchange efficiently using a frequency band in such a manner that a transmission signal sent from the IC card processor is received by an antenna, the ... | 05/20/2003 |
| 6531935 | Vector modulator An analogue phase shifter with vector modulator is envisioned. The analogue phase shifter has an input stage that provides the generation of a pseudo-basis of four vectors. The analogue phase shifter has a multiphase filter. The analogue phase shifter has... | 03/11/2003 |
| 6532270 | Apparatus and method for broadcast band noise reduction in a transmitter with a low IF frequency In the broadcast band having a plurality of channels allocated therein, by using high-side injection and low-side injection as described herein, the noise introduced into the channel by the local oscillator signal can be minimized. The local oscillator si... | 03/11/2003 |
| 6522213 | SSB transmitter In an SSB transmitter, a problem such that the central frequency of a BPF for extracting one of sideband signals from the modulated signals obtained by modulating a carrier frequency signal by an input sound signal is changed by temperatures, causing a dr... | 02/18/2003 |
| 6496545 | Single side-band mixer In accordance with the invention, a single sideband mixer includes first and second all-pass 90° phase shifters. Each phase shifter produces two outputs of substantially equal amplitude but subject to a phase angle error (θ) indicative of a deviation fr... | 12/17/2002 |
| 6351500 | AM- compatible digital broadcasting method and system A method and system are provided for the transmission and reception of a composite radio-frequency (RF) signal including a supplemental signal, preferably representing encoded digital information, together with an analog signal which represents monophonic... | 02/26/2002 |
| 6148320 | Multichannel digital signal generation method and apparatus A multichannel television access control system is disclosed wherein processing of the broadband signal is performed by gated coherent RF injection on a plurality of channels, thereby effecting selective descrambling of an arbitrary subset of channels in ... | 11/14/2000 |
| 6091303 | Method and apparatus for reducing oscillator noise by noise-feedforward A circuit for reducing phase noise in a transmitted radio signal includes a first phase-locked loop circuit including a first controlled oscillator generating a first output signal at a first desired frequency, and a first phase comparator developing a fi... | 07/18/2000 |
| 6005894 | AM-compatible digital broadcasting method and system A method and system are provided for the transmission and reception of a composite radio-frequency (RF) signal including a supplemental signal, preferably representing encoded digital information, together with an analog signal which represents monophonic... | 12/21/1999 |
| 5861781 | Single sideband double quadrature modulator A method of and apparatus for effecting single sideband modulation which mixes and sums the quadrature and in-phase components of a baseband signal with the in-phase and quadrature components of an intermediate frequency (IF) signal to form in-phase and q... | 01/19/1999 |
| 5822685 | Modulating reflector circuit A modulating reflector circuit arrangement comprising a transistor configured by means of a feedback arrangement upon operation within a linear region of the transistor's current/voltage characteristic to reflect an incoming amplitude modulated signal wit... | 10/13/1998 |
| 5815532 | Method and apparatus for peak-to-average ratio control in an amplitude modulation paging transmitter A method and apparatus for reducing peak-to-average power ratio in a paging transmitter broadcasting an independent sideband amplitude modulation protocol is disclosed. A digital signal, for example a digital voice signal, is provided to a control gain ge... | 09/29/1998 |
| 5801595 | Device and method for digital vestigial sideband modulation A digital signal processing device and method for vestigial sideband (VSB) modulation of a digital signal. A 2n -ary digital signal di is provided to a baseband shaping filter which samples the signal to provide a baseband signal whi... | 09/01/1998 |
