Patents Assigned to Broadcom Corporation
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Publication number: 20070046334Abstract: A high speed data communication system uses a single-ended bus architecture with a reference signal extracted from a differential periodic signal that is transmitted along with single-ended data. By using a periodic signal such a clock signal with approximately 50% duty cycle, a much more stable and accurate reference signal is established for receiving single-ended data.Type: ApplicationFiled: November 1, 2006Publication date: March 1, 2007Applicant: Broadcom CorporationInventor: Armond Hairapetian
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Publication number: 20070045824Abstract: An electrically and thermally enhanced die-up tape substrate ball grid array (BGA) package and die-up plastic substrate BGA package are described. A substrate that has a first surface and a second surface is provided. The stiffener has a first surface and a second surface. The second stiffener surface is attached to the first substrate surface. An IC die has a first surface and a second surface. The first IC die surface is mounted to the first stiffener surface. A plurality of solder balls is attached to the second substrate surface. In one aspect, a heat spreader is mounted to the second IC die surface. In another aspect, the stiffener is coupled to ground to act as a ground plane. In another aspect, the substrate has a window opening that exposes a portion of the second stiffener surface. The exposed portion of the second stiffener surface is configured to be coupled to a printed circuit board (PCB). In another aspect, a metal ring is attached to the first stiffener surface.Type: ApplicationFiled: August 25, 2006Publication date: March 1, 2007Applicant: Broadcom CorporationInventors: Sam Zhao, Rezaur Khan
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Publication number: 20070050617Abstract: A method for processing wireless data packets allows for processing packets allows consolidation of security processing. Security processing is performed in accordance with multiple security policies. This processing is done in a single front end processing block. Different security processes can be performed in parallel. Processing overhead is reduced by eliminating the need to redundantly check packet characteristics to assess the different security requirements imposed by security policies. Further, the present invention also substantially reduces the CPU cycles required to transport data back and forth from memory to a cryptographic coprocessor.Type: ApplicationFiled: October 31, 2006Publication date: March 1, 2007Applicant: Broadcom CorporationInventor: Jeffrey Carr
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Publication number: 20070049220Abstract: A transmitter includes a first mixer to generate a first output signal by up-converting a first baseband signal having a first DC offset component. A second mixer generates a second output signal by up-converting a second baseband signal having a second DC offset component. The second output signal is subtracted from the first output signal to generate a transmitter output signal. The transmitter output signal includes a local oscillator (LO) leakage signal caused by the first and/or second DC offset components. A third mixer produces a third output signal by up-converting the first DC offset component. A fourth mixer produces a fourth output signal by up-converting the second DC offset component. The fourth output signal is subtracted from the third output signal to generate a LO leakage cancellation signal. The LO leakage cancellation signal is subtracted from the transmitter output signal, thereby reducing a power of the LO leakage signal.Type: ApplicationFiled: August 26, 2005Publication date: March 1, 2007Applicant: Broadcom CorporationInventor: Meng-An Pan
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Publication number: 20070046271Abstract: A low-power programmable low-drop-out voltage regulator system and methods are presented. The regulator includes a local reference generator circuit that receives a voltage input signal and outputs a reference voltage signal, a buffer circuit that receives the reference voltage signal and outputs an output voltage signal, and a comparison device. The comparison device receives and compares the output voltage signal and an accurate reference voltage signal and outputs an adjustment signal to adjust the output voltage signal in the direction of a value of the accurate reference voltage signal. The regulator can include an attenuator circuit to attenuate the reference voltage signal. The output voltage signal can be regulated or programmed by adjusting the gain of the buffer circuit and/or the attenuator circuit. Current consumption can also be programmed by turning on or off one or more amplifier tiers located in the buffer circuit.Type: ApplicationFiled: August 31, 2005Publication date: March 1, 2007Applicant: Broadcom CorporationInventor: Alireza Zolfaghari
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Patent number: 7184468Abstract: Provided is a system and method for a modem including one or more processing paths. Also included is a number of interconnected modules sequentially arrayed along the one or more paths. Each module is configured to (i) process signals passed along the paths in accordance with the sequence and (ii) implement predetermined functions to perform the processing. Further, each of the modules has a particular degree of functional programmability and the degrees of functional programmability monotonically vary in accordance with the sequence.Type: GrantFiled: January 24, 2003Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventor: Gregory H. Efland
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Patent number: 7185270Abstract: LDPC (Low Density Parity Check) coded modulation hybrid decoding. A novel approach is presented wherein a combination of bit decoding and symbol level decoding (e.g., hybrid decoding) is performed for LDPC coded signals. Check node updating and symbol node updating are successively and alternatively performed on bit edge messages for a predetermined number of decoding iterations or until a sufficient degree of precision is achieved. The symbol node updating of the bit edge messages involves using symbol metrics corresponding to the symbol being decoded as well as the bit edge messages most recently updated by check node updating. The check node updating of the bit edge messages involves using the bit edge messages most recently updated by symbol node updating. The symbol node updating also involves computing possible soft symbol estimates for the symbol during each decoding iteration.Type: GrantFiled: November 26, 2003Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventors: Ba-Zhong Shen, Hau Thien Tran, Kelly Brian Cameron
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Patent number: 7184058Abstract: A graphics integrated circuit chip is used in a set-top box for controlling a television display. The graphics chip processes analog video input, digital video input, a graphics input and an audio input simultaneously. The system may use anti-aliased text and graphics to provide high quality display of graphical elements, or glyphs, which represent an image of a character of text or graphics, on television and other displays. The graphical elements may be superimposed over live video or arbitrary graphics imagery.Type: GrantFiled: April 14, 2005Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventors: Alexander G. MacInnis, Chengfuh Jeffrey Tang, Xiaodong Xie, James T. Patterson, Greg A. Kranawetter
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Patent number: 7184404Abstract: A process of generating an inter-packet gap in a network device is disclosed. First, it is determined whether a next packet is available to forward from a packet buffer. The number of tokens contained in a token bucket is checked and bytes are added to the inter-packet gap and tokens are added to the token bucket, when the number of tokens contained in a token bucket is less than a predetermined number of tokens. Otherwise, the size of the inter-packet gap is reduced and tokens are taken out of the token bucket, when the number of tokens contained in a token bucket is greater than or equal to the predetermined number of tokens. Thereafter, the inter-packet gap is supplied and sent with the next packet over an interface between the network device and a network.Type: GrantFiled: October 15, 2002Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventors: Johnson Yen, Michael Veng-Chong Lau
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Patent number: 7183845Abstract: A Variable Gain Amplifier (VGA) amplifies an input signal according to a gain, to produce an amplified signal. A detector module detects a power indicative of a power of the amplified signal. A comparator module compares the detected power to a high threshold, a low threshold and a target threshold intermediate the high and low thresholds. A controller module changes the gain of the VGA so as to drive the detected power in a direction toward the middle threshold when the comparator module indicates the detected power is not between the high and low thresholds.Type: GrantFiled: May 2, 2005Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventors: Leonard Dauphinee, Lawrence M. Burns
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Patent number: 7183858Abstract: A method and apparatus are provided for enabling a transmitter to have a substantially linear magnitude response and a substantially linear phase response. The transmitter includes first and second programmable gain amplifiers (PGAs). The first PGA is tuned to have a resonant frequency that is less than an operating frequency of the first PGA. The second PGA is tuned to have a resonant frequency that is greater than an operating frequency of the second PGA. A magnitude response at an output of the first PGA and a magnitude response at an output of the second PGA combine to provide a substantially linear magnitude response across a frequency range that includes the operating frequency of the first or second PGA. According to an embodiment, the first and second PGAs have the same operating frequency.Type: GrantFiled: March 31, 2005Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventor: Meng-An Pan
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Patent number: 7184471Abstract: A modem receiver 10 receives a multitone signal with a cyclic extension of M samples on a channel 20. The receiver includes a time domain equalizer 14 that includes a finite impulse response (FIR) filter. The FIR filter targets the combined response of the channel and filter to a target impulse response having N taps, where N is less than M+1.Type: GrantFiled: February 13, 2002Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventor: Miguel Peeters
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Patent number: 7184737Abstract: In a communications receiver for quadrature demodulation, a feedback technique for reducing the image response of the receiver. The communications receiver includes an I demodulator and a Q demodulator. A local oscillator (LO) signal is provided by a PLL to a quadrature LO generator that provides an LO_I signal to an I demodulator and an LO_Q signal to a Q demodulator. The LO_I and LO_Q signals are amplitude and phase-controlled versions of the LO signal. An image/signal ratio (I/S) detector detects the relative phase difference and the relative amplitude difference between the respective output terminals of the I demodulator and the Q demodulator and applies an amplitude control signal and a phase control signal to corresponding amplitude control and phase control inputs of the quadrature LO generator. The I/S detector calibrates the quadrature LO generator during the interstitial interval between the reception of data packets.Type: GrantFiled: March 21, 2003Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventor: Bin Liu
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Patent number: 7184441Abstract: A network switch stack configuration includes a first network switch having a plurality of data ports, a first stacking port, and a first CPU interface. A second network switch has a plurality of data ports, a second stacking port, and a second CPU interface. A common CPU is connected to the first CPU interface and the second CPU interface, such that the first stacking port and the second stacking port are communicatively connected. Therefore incoming packets on any of the plurality of data ports on the first and second switches can be effectively switched to any of the plurality of data ports on either of the first and second network switches.Type: GrantFiled: March 17, 2000Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventors: Shiri Kadambi, Shekhar Ambe
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Patent number: 7184506Abstract: Improved frequency drift and phase error compensation in a VOFDM receiver. The invention is operable to compensate for frequency drift and phase error within a window that may include a single frame, a sub-frame, or multiple frames. The compensation is performed after having performed estimation of the phase within the particular window; any phase error and frequency drift may be identified and an appropriate form of compensation may be identified to perform curve fitting of the phase within the compensation window. The curve fitting of the phase is performed using linear techniques in one embodiment; an average phase and appropriate slope/ramp are calculated to match the phase as accurately as possible. Other alternative compensation techniques may also be performed, including higher order curve matching techniques. The receiver is operable to perform any necessary compensation before passing the now-compensated data to a symbol processing functional block.Type: GrantFiled: March 30, 2002Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventor: Thomas J. Kolze
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Patent number: 7184735Abstract: A radio frequency circuit includes a first differential RF path and a second differential path. The first differential RF path includes at least one RF block that includes a first differential section and a second differential section, wherein the first differential section is symmetrical with the second differential section. The second differential RF path includes at least one RF block that includes a first differential section and a second differential section, wherein the first differential section is symmetrical with the second differential section. The first and second half differential sections of the at least one RF block of the first differential RF path are symmetrically placed on at least one layer around the first and second half differential sections of the at least one RF block of the second differential RF path, wherein the first and second half differential sections of the at least one RF block of the second differential RF path are fabricated on the at least one layer.Type: GrantFiled: August 21, 2003Date of Patent: February 27, 2007Assignee: Broadcom CorporationInventors: Iqbal S. Bhatti, Rozi (Razieh) Roufoogaran
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Publication number: 20070042728Abstract: A transmitter generates a transmitter output signal from first and second baseband signals. The transmitter includes a detector to detect a local oscillator (LO) leakage signal in the transmitter output signal. A controller coupled to the detector determines a direct LO coupling component and a baseband DC offset component of the LO leakage signal. First and second variable current sources are adjusted by the controller to provide first and second DC offsets to the first and second baseband signals, respectively. The first and second DC offsets reduce the direct LO coupling component. Third and fourth variable current sources are subsequently adjusted by the controller to provide third and fourth DC offsets to the first and second baseband signals, respectively. The third and fourth DC offsets reduce the baseband DC component. Overall, reducing the direct LO coupling component and the baseband DC component reduces a power of the LO leakage signal.Type: ApplicationFiled: August 16, 2005Publication date: February 22, 2007Applicant: Broadcom CorporationInventor: Meng-An Pan
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Publication number: 20070040537Abstract: A switching regulator automatically operates in pulse width modulation (“PWM”) mode for high load currents and in burst mode for low load currents. The switching regulator includes a pair of switches to provide a regulated current to a load. The switching regulator further includes a multi-input comparator. A first input of the comparator is coupled to an output of the pair of switches. A second input of the comparator is coupled to a filtered version of the output and a third input is coupled to a reference waveform. The first, second and third inputs of the comparator form a combined input signal to the comparator. An output signal of the comparator is generated by comparing the combined input signal to a threshold of the comparator. The output signal determines a switching frequency of the pair of switches such that the switching frequency is automatically reduced when the load is decreased.Type: ApplicationFiled: July 28, 2006Publication date: February 22, 2007Applicant: Broadcom CorporationInventors: Khim Low, David Ho, Chi-Ming Hsiao, Hua Chan
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Publication number: 20070041478Abstract: Modified branch metrics for processing bit-soft decisions to account for phase noise impact on cluster variance (CV). The present invention is able to partition a modulation scheme's constellation into two or more regions, so that the bit-soft decision branch metrics may be adjusted based on the CV of the various constellation points. A confidence level may be attached to the various constellation points based on their particular CVs. There are a number of methods to ascertain the CV of the constellation's points, including finding characteristics of various components in a communication system (transmitter, communication channel and receiver), and any method may be used within various embodiments. The modification of the branch metrics/confidence level may be performed in a communication receiver; the communication receiver may be implemented in a communication system employing the vector orthogonal frequency division multiplexing (VOFDM) portion of the broadband wireless internet forum (BWIF).Type: ApplicationFiled: October 31, 2006Publication date: February 22, 2007Applicant: Broadcom Corporation, a California CorporationInventor: Thomas Kolze
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Characterizing channel response in a single upstream burst using redundant information from training
Publication number: 20070041477Abstract: Characterizing channel response in a single upstream burst using redundant information from training tones (TTs). The invention is operable to utilize inserted TTs, contained within a transmitted data frame, to provide for an improved estimate of a communication channel's actual response and an improved estimate of the noise of the communication channel. The invention determines a maximum allowable delay spread of the many communication paths within a multi-path communication channel. Using the redundant TTs information then a portion of the finite impulse response of the communication channel, within the time domain, may be zeroed, thereby providing a much improved channel estimate and noise estimate. Using the redundant TTs, less noise is introduced onto the data tones (DTs) within a data frame. The present invention is also able to identify those portions of the TTs that are attributable to the actual channel and those that are attributable to the channel's noise.Type: ApplicationFiled: October 31, 2006Publication date: February 22, 2007Applicant: Broadcom Corporation, a California CorporationInventor: Thomas Kolze