Patents Assigned to Conexant System, Inc.
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Patent number: 6181218Abstract: The invention provides a unique apparatus and method which varies the capacitance coupled to a circuit. In one embodiment, the variable capacitance comprises a unique variable capacitance array with multiple capacitance modules which can be selectively enabled. Each capacitance module has a capacitive value and a corresponding parasitic capacitance. The invention provides high linearity, low spread, improves the response to power fluctuations by maintaining a consistent relationship between the capacitive value and the parasitic capacitance in each capacitance module. For example, the invention can be used with devices to provide a linear variation of capacitance. In addition, the invention can be used to calibrate a wide range of devices.Type: GrantFiled: May 19, 1998Date of Patent: January 30, 2001Assignee: Conexant Systems, Inc.Inventors: Ricke W. Clark, Jorge A. Grilo, Bo Zhang
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Patent number: 6181350Abstract: An image has a portion formulated partially from graphics pixels and partially from video pixels. This image portion is interpolated to provide an enlargement of such image portion. The interpolation or enlargement may be provided sequentially in two (2) coordinate directions (e.g. horizontal and vertical) or alternatively in only one of such directions. The enlargement may be alternatively provided simultaneously in both coordinate directions. The enlargement of the image portion in each of the coordinate directions may be obtained by interpolating video pixel(s) in such coordinate direction between each pair of adjacent video pixels in such coordinate direction and by otherwise interpolating graphics pixel(s) between such pair of adjacent pixels in such coordinate direction. In other words, graphics pixel(s) may be provided between each pair of adjacent pixels in each of the coordinate directions when one or both of the adjacent pixels in such pair are graphics.Type: GrantFiled: May 20, 1996Date of Patent: January 30, 2001Assignee: Conexant Systems, Inc.Inventor: James Corona
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Patent number: 6175389Abstract: An adaptive signal separation system and method for quadrature amplitude modulated signals that is particularly well-suited for YC separation of a composite television signal. An adaptive approach for separating overlapping signals wherein the adaptive approach selects between notch or equivalent filtering and a comb filtering system, wherein the chrominance is first demodulated to the IQ domain prior to comb filtering. The demodulated comb filtered IQ data streams are then re-modulated to reconstruct the luminance portion of the signal.Type: GrantFiled: February 4, 1999Date of Patent: January 16, 2001Assignee: Conexant Systems, Inc.Inventors: Benjamin E. Felts, III, John E. Welch
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Patent number: 6173257Abstract: A multi-rate speech codec supports a number of encoding bit rate modes by adaptively selecting encoding bit rate modes to match communication channel restrictions. In higher bit rate encoding modes, an accurate representation of speech through CELP (code-excited linear prediction) and other associated modeling parameters are generated for higher quality decoding and reproduction. To achieve high quality in high lower bit rate encoding modes, the speech encoder departs from the strict waveform matching criteria of regular CELP coders and strives to identify significant perceptual features of the input signal. To support lower bit rate encoding modes, a variety of techniques are applied, many of which involve the classification of the input signal. For each of the bit rate modes selected, a number of fixed or innovation sub-codebooks are selected in use in generating innovation vectors.Type: GrantFiled: September 18, 1998Date of Patent: January 9, 2001Assignee: Conexant Systems, IncInventor: Yang Gao
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Patent number: 6166585Abstract: A charge pump circuit includes MOS capacitors configured to operate in the accumulation region, resulting in a substantially constant capacitance over the operational range. In a particularly preferred embodiment, a char ge pump uses multiple stages of p-channel MOS capacitors. In accordance with a further aspect of the present invention, oxide thicknesses of the p-channel MOS capacitors are optimized in accordance with the requirements of each stage.Type: GrantFiled: August 31, 1998Date of Patent: December 26, 2000Assignee: Conexant Systems, Inc.Inventor: Cristiano Bazzani
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Patent number: 6163570Abstract: A pulse code modulation modem system utilizes the same total average transmit power formula for designing signal point constellations and for verifying that the transmit power of the signal point constellations are within a designated maximum power limit. The transmit power of the signal point constellations designed by the client modem is also calculated by the server modem to verify that the transmit power limit imposed upon the server modem is not exceeded. In addition, the modem system is capable of designating a transmit power limit associated with one or more training signal points or a training sequence for use during a training mode.Type: GrantFiled: May 11, 1998Date of Patent: December 19, 2000Assignee: Conexant Systems, Inc.Inventor: Sverrir Olafsson
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Patent number: 6163709Abstract: A transmitter for a cellular phone comprising an antenna and being operable at a first radio frequency band and a second radio frequency band is disclosed. In one embodiment, the transmitter includes a first power amplifier and a second power amplifier. The first power amplifier has a first input for a first signal at the first radio frequency band and a first output for an amplified first signal, the first output being connected to the antenna. The second power amplifier has a second input for a second signal at the second radio frequency band and a second output for an amplified second signal, the second output being connected to the antenna. The transmitter further comprises a single control module which is associated with the first and second outputs of the power amplifiers and comprises a logarithmic detector. The control module generates a control signal which is a function of an amplified signal and a reference signal in order to control the two power amplifiers.Type: GrantFiled: June 24, 1998Date of Patent: December 19, 2000Assignee: Conexant Systems, Inc.Inventors: Christopher M. Chorey, Iconomos A. Koullias, Luke T. Steigerwald
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Patent number: 6163706Abstract: A system and method for minimizing power dissipation in a battery-operated mobile unit by adaptively controlling a voltage converter to provide a variable power supply voltage to a transmitter. In the preferred embodiment, the voltage converter is coupled to receive a source voltage from a battery, and is coupled to provide operating power to the transmitter or the power amplifier. The voltage converter is also coupled to receive a control signal from a controller, which adaptively activates the voltage converter to transform the source voltage to a converted voltage, or deactivates the voltage converter so as to directly apply the source voltage to the transmitter. Power dissipation is therefore minimized when conversion functions of the voltage converter are deactivated when voltage conversion is unnecessary.Type: GrantFiled: November 18, 1997Date of Patent: December 19, 2000Assignee: Conexant Systems, Inc.Inventors: Dmitriy Rozenblit, Mark Oskowsky, William J. Domino
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Patent number: 6163845Abstract: An apparatus and method for power management of embedded electronic subsystems. A power management control circuit for managing power to an embedded subsystem includes a subsystem power node connected to a first section of the embedded electronic subsystem and a bias voltage node connected to a second section of the embedded electronic subsystem. A power switch is connected between a power supply and the subsystem power node. By separating the power subsystem node from the bias voltage node, power can be removed from the subsystem, while still providing the necessary bias voltage to the electronic static discharge (ESD) diodes. This prevents the voltages applied to the system bus by the subsystem from causing bus contention or system bus lock-ups. A power removal and restoration procedure is also disclosed.Type: GrantFiled: October 2, 1998Date of Patent: December 19, 2000Assignee: Conexant Systems, Inc.Inventors: Dongfeng Zhao, F. Matthew Rhodes
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Patent number: 6161203Abstract: A digital subscriber line communication system does not require the use of a plain old telephone service (POTS) splitter in the resident's home. Digital signal processing is utilized to adapt to varying subscriber line conditions coming from POTS telephone equipment. The digital subscriber line modem includes a control circuit that utilizes a Reed-Solomon decoder and a synchronization error generator. The Reed-Solomon decoder provides a frame error signal, and the synchronization error generator responds to the frame error signal to generate a synchronization error signal. The synchronization error generator is configured as a leaking integrator to provide the synchronization error signal in response to a relatively large number of frame error signals occurring in a period of time. A resynchronization operation is performed in the modem in response to the synchronization error signal.Type: GrantFiled: February 23, 1998Date of Patent: December 12, 2000Assignee: Conexant Systems, Inc.Inventors: Edward S. Zuranski, Kenneth D. Ko, Jamal Haque, Shrenik P. Patravali, Manuel I. Rodriguez, Keith A. Souders, Anthony A. Tzouris
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Patent number: 6160432Abstract: A source-switched or gate-switched charge pump having a cascoded output. A first current-mirror comprised of p-channel CMOS transistors is coupled on one side of an output node and a second current mirror comprised of n-channel CMOS transistors is coupled on the opposite side of the output node. A reference current source is coupled between the current mirrors. A p-channel CMOS cascode transistor is coupled between the first current mirror and the output node, and an n-channel CMOS cascode transistor is coupled between the second current mirror and the output node. A p-channel CMOS transistor switch is coupled to either the source or the gate of the output transistor of the first current mirror and receives a first control signal at its gate. An n-channel CMOS transistor switch is coupled to either the source or the gate of the output transistor of the second current mirror and receives a second control signal at its gate.Type: GrantFiled: April 30, 1999Date of Patent: December 12, 2000Assignee: Conexant Systems, Inc.Inventors: Woogeun Rhee, Matteo Conta
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Patent number: 6160427Abstract: A transfer function generator which generates an output that is a cubic function of the input for use in low voltage, high frequency applications. The cubic function generator creates a signal path through high speed npn devices, thereby allowing the use of high frequencies. Further, the topography of the cubic function generator requires a voltage drop across only two semiconductor devices, thereby allowing use of the circuit in low voltage applications.Type: GrantFiled: September 4, 1998Date of Patent: December 12, 2000Assignee: Conexant Systems, Inc.Inventors: Stefano Cipriani, Anthony A. Takeshian
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Patent number: 6157693Abstract: A prescaler circuit for a frequency synthesizer includes two circuit blocks, each having an OR gate coupled with a master-slave flip-flop. An input clock signal having a frequency FN is supplied to the flip-flop of each circuit block, and an output clock signal having a frequency FN/2 or FN/3 is generated in response. A control signal supplied to the OR gate of the second circuit block determines whether the frequency will be divided by 2 or by 3. The circuit blocks generate differential output signals, and common-mode signals are generated for supply to the OR gate inputs by summing and dividing the differential output signals with high value resistors.Type: GrantFiled: September 30, 1998Date of Patent: December 5, 2000Assignee: Conexant Systems, Inc.Inventor: Arun Jayaraman
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Patent number: 6157257Abstract: A folding amplifier in which a single tail current is used to service all differentially coupled transistor pairs in the amplifier. The input signal applied to each differential pair of transistors is used to drive a switch which controls the tail current to that specific differential pair. When a differential pair is fully switched in either direction, the associated tail current switch is open. As the input signal applied to the differential pair causes the pair to pass through its active region, the switch associated with that pair closes to allow current to be conducted through that pair. Therefore, the tail current has a path which is primarily through a single differential pair at any given time.Type: GrantFiled: June 30, 1999Date of Patent: December 5, 2000Assignee: Conexant Systems, Inc.Inventor: Anna Murphy
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Patent number: 6154664Abstract: A transmitter for a cellular phone comprising an antenna and being operable at a first radio frequency band and a second radio frequency band is disclosed. The transmitter comprises a first power amplifier and a second power amplifier, one of which is active at a time. The first power amplifier has an input for a first signal at the first radio frequency band, an input for a first control signal and a first output for an amplified first signal. The first output is connectable to the antenna. The second power amplifier has an input for a second signal at the second radio frequency band, an input for a second control signal and a second output for an amplified second signal. The second output is connectable to the antenna. The transmitter further comprises a single control module associated with the first and second outputs of the power amplifiers. The control module generates a control signal for the active power amplifier.Type: GrantFiled: June 24, 1998Date of Patent: November 28, 2000Assignee: Conexant System, Inc.Inventors: Christopher M. Chorey, Iconomos A. Koullias, Luke T. Steigerwald
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Patent number: 6153955Abstract: A digital image printer that performs certain digital image processing functions using parallel integrated circuitry and other functions using serial integrated circuitry in an effort to minimize integrated circuit real estate. The serial integrated circuitry is allocated to certain functions within digital image printing system that perform various mechanical operations. The inherent mechanical time constant of these mechanical operations, when compared to electrical digital image processing operations performed using modern integrated circuitry, is relatively long. In other words, the mechanical operations are performed in a relatively longer time than is made possible using modern integrated circuitry and processors employed within digital image printing systems. The present invention dedicates certain of the functions used to perform digital image processing to be performed using slower, serial integrated circuitry.Type: GrantFiled: April 1, 1999Date of Patent: November 28, 2000Assignee: Conexant Systems, Inc.Inventors: Chong-Hing Cheung, Hua Peng
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Patent number: 6150890Abstract: Disclosed is a dual band wireless phone, such as a cellular phone for a mobile communications system, with a dual band transmitter that includes a phase-locked loop (PLL). The dual band transmitter includes first and second power amplifiers and the PLL. The first power amplifier has a first input for a first signal at a first radio frequency band, and a first output for an amplified first signal. The second power amplifier has a second input for a second signal at a second radio frequency band and a second output for an amplified second signal. The outputs of the power amplifiers are connectable to an antenna. The PLL generates two output frequency ranges and includes a voltage-controlled oscillator (VCO) which has a first output connected to the first power amplifier and generates a first signal. A frequency multiplier has an input connected to the first output of the VCO and a second output connected to the second power amplifier.Type: GrantFiled: September 30, 1998Date of Patent: November 21, 2000Assignee: Conexant Systems, Inc.Inventors: Morten Damgaard, Leo L. Li
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Patent number: 6151509Abstract: A transmitter for a cellular phone comprising an antenna and being operable at a first radio frequency band and a second radio frequency band is disclosed. The transmitter comprises a first power amplifier and a second power amplifier. The first power amplifier has a first input for a first signal at the first radio frequency band, a second input for a first control signal and a first output for an amplified first signal. The first output is connectable to the antenna. The second power amplifier has a third input for a second signal at the second radio frequency band, a fourth input for a second control signal and a second output for an amplified second signal. The second output is connectable to the antenna. The transmitter further comprises a single control module which receives a signal indicative of a current an active power amplifier draws. The control module uses this signal indicating the drawn current to generate a control signal to control the active power amplifier.Type: GrantFiled: June 24, 1998Date of Patent: November 21, 2000Assignee: Conexant Systems, Inc.Inventor: Christopher M. Chorey
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Patent number: 6151335Abstract: A digital subscriber line (DSL) communication system that utilizes the high frequency band of a standard telephone line does not require the use of a plain old telephone service (POTS) splitter in the resident's home, which provided isolation between the POTS frequency band (0 to 4 kHz) and the DSL frequency band. A digital subscriber line modem utilizes either constant envelope modulation or quadrature amplitude modulation for outputting DSL signals upstream to a central office. When a telephone in the resident's home is detected as being off-hook, then the constant envelope modulation is used by the DSL modem in order to lessen the intermodulation product distortion that results in audible noise heard by a user of the telephone. When the telephone is on-hook, then another type of modulation, such as QAM, is used to maximize the upstream data rate capability in the DSL frequency band, since any noise generated by the QAM is not a problem due to the non-use of the POTS frequency band.Type: GrantFiled: December 2, 1997Date of Patent: November 21, 2000Assignee: Conexant Systems, Inc.Inventors: Kenneth D. Ko, David O. Anderton, Ismail I. Eldumiati, Steven A. Gronemeyer, Don L. Harmer, P. Michael Henderson, Joel D. Peshkin, Raphael Rahamim, Frederic M. Stubbe, John S. Walley, Kenneth S. Walley, Yongbing Wan, Edward S. Zuranski, Jamal Haque, Anthony A. Tzouris, Shrenik P. Patravali, Ganning Yang
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Patent number: 6147561Abstract: A phase locked loop (PLL) circuit with time-delayed phase/frequency detector (PFD) input signals and a method for generating high PFD gain in such a circuit is provided. One circuit embodiment includes a first divider, a phase/frequency detector having a plurality of input pairs, a plurality of input signal reference delay elements connected in a series between the first divider and the PFD, a charge pump, a loop filter, a voltage-controlled oscillator (VCO), a second divider, and a plurality of feedback signal delay elements connected in a series. The corresponding method embodiment includes steps for receiving digital input signals with reference frequency and period T in the first divider, dividing the reference frequency by a value R, providing a plurality of time-delayed PFD reference input signals in each period T, dividing the VCO frequency by a value M in the second divider, and providing a plurality of time-delayed PFD feedback input signals in each period T.Type: GrantFiled: July 29, 1999Date of Patent: November 14, 2000Assignee: Conexant Systems, Inc.Inventors: Woogeun Rhee, Akbar Ali