Abstract: A method and apparatus for efficiently deriving modulo arithmetic solutions for frequency selection in transceivers. A frequency for communication between a wireless user interface device and a wirelessly enabled host is generated by calculating a modulo solution for an input variable. In some embodiments of the invention, the communication between the user input device and the wirelessly enabled host complies with the Bluetooth wireless communication standard. For the embodiments of the present invention relating to communications systems implementing the Bluetooth standard, a method and apparatus is disclosed for generating communication frequencies based on modulo 23 and modulo 79 solutions input variables. The method and apparatus of the present invention can generate the communication frequency with a minimum number of calculations using simple binary addition, as opposed to prior art methods that generally require numerous iterations and complex calculations.

Abstract: A Radio Frequency (RF) structure services an antenna having a characteristic impedance and includes a differential Power Amplifier (PA), a differential Low Noise Amplifier (LNA), and a balun transformer. The differential PA has a differential PA output with a PA differential output impedance. The differential LNA has a differential LNA input with an LNA differential input impedance. The balun transformer has a singled ended winding coupled to the antenna, a differential winding having a first pair of tap connections coupled to the differential PA output and a second pair of tap connections coupled to the differential LNA input, and a turns ratio of the single ended winding and the differential winding. The turns ratio and the first pair of tap connections impedance match the PA differential output impedance to the characteristic impedance of the antenna. The turns ratio and the second pair of tap connections impedance match the LNA differential input impedance to the characteristic impedance of the antenna.

Abstract: Implementation of LDPC (Low Density Parity Check) decoder by sweeping through sub-matrices. A novel approach is presented by which an LDPC coded signal is decoded processing the columns and rows of the individual sub-matrices of the low density parity check matrix corresponding to the LDPC code. The low density parity check matrix can partitioned into rows and columns according to each of the sub-matrices of it, and each of those sub-matrices also includes corresponding rows and columns. For example, when performing bit node processing, the same columns of at 1 or more sub-matrices can be processed together (e.g., all 1st columns in 1 or more sub-matrices, all 2nd columns in 1 or more sub-matrices, etc.). Analogously, when performing check node processing, the same rows of 1 or more sub-matrices can be processed together (e.g., all 1st rows in 1 or more sub-matrices, all 2nd rows in 1 or more sub-matrices, etc.).

Abstract: Sub-matrix-based implementation of LDPC (Low Density Parity Check) decoder. A novel approach is presented by which an LDPC coded signal is decoded by processing 1 sub-matrix at a time. A low density parity check matrix corresponding to the LDPC code includes rows and columns of sub-matrices. For example, when performing bit node processing, 1 or more sub-matrices in a column are processed; when performing check node processing, 1 or more sub-matrices in a row are processed. If desired, when performing bit node processing, the sub-matrices in each column are successively processed together (e.g., all column 1 sub-matrices, all column 2 sub-matrices, etc.). Analogously, when performing check node processing, the sub-matrices in each row can be successively processed together (e.g., all row 1 sub-matrices, all row 2 sub-matrices in row 2, etc.).

Abstract: A printed circuit board includes two differential signal traces, a layer of core material, a layer of filler material, and a ground plane. The filler material is replaced by an air core under the differential signal traces.

Abstract: A method and apparatus to counter effects of an offset voltage by calibrating an analog-to-digital converter (ADC). A digital calibration loop minimizes the effects of offset voltage to improve ADC accuracy as well as provide a low-power, submicron-scale ADC. A calibration circuit senses an ADC output and adjusts a variable calibration voltage to counter the effects of the offset voltage. Reduction of the offset voltage effects increases the ADC accuracy.

Abstract: A system and method for determining whether to process a signal using three-dimensional comb filtering. Various aspects of the present invention may comprise method steps and system components that generate an inter-frame chroma signal. Various aspects may generate a filtered inter-frame chroma signal by removing a band of frequency components from the inter-frame chroma signal that generally corresponds to chroma signal components. Various aspects may analyze the filtered inter-frame chroma signal to determine whether three-dimensional comb filtering may be appropriate. Various aspects may comprise method steps and components that generate inter-frame and intra-frame luma signals. Various aspects may generate filtered inter-frame and intra-frame luma signals by removing frequency components from the inter-frame and intra-frame luma signals, respectively, that fall outside a frequency band near the chroma sub-carrier frequency.

Abstract: RF communications received by a wireless terminal from a servicing base station are used to determine the channel quality such as reported bit error probability (BEP). The RF communications may be in the form of RF bursts that are part of a data frame. An estimated BEP may be determined from the signal to noise ratio (SNR) of the RF bursts and or a sequence of soft decisions extracted from the RF bursts, and their historical performance. The SNR maps to an estimated BEP based upon the modulation format of the RF bursts. The soft decisions decode to produce a data block. When the soft decisions decoded favorably, the re-encoded data block produces a sequence of re-encoded decisions. Comparing the re-encoded decisions to the soft decisions yields a re-encoded bit error (RBER). The reported BEP may be based upon the estimated BEP, RBER, and/or RBER threshold. The RBER threshold may be adaptively incremented or decremented depending upon whether or not the RF communications were properly decoded.

Abstract: The present invention relates to a system and method for improving the waveform at a receiver. More specifically, the present invention relates to a system adapted to modify at least one signal in anticipation of channel attenuation and delay. The present invention comprises a memory adapted to store at least one coefficient that is pre-determined based on at least one expected degradation characteristic of a channel; and a pre-emphasizer communicating with at least the memory and the channel, and adapted to modify the at least one signal using the at least one coefficient prior to transmission of the at least one signal over the channel, compensating for the at least one expected degradation characteristic.

Abstract: An n-level look-ahead network converts input values to intermediate values that are provided to a plurality of multiplexers arranged to form a pipelined multiplexer loop. The first stage of the multiplexer loop consists of a single multiplexer. The second stage consists of at least two multiplexers. Communication links couple the output ports of the second stage multiplexers to the input ports of the first stage multiplexer. A first feedback loop electrically couples the output port of the first stage multiplexer to the control port of the first stage multiplexer. This first feedback loop has a first delay device having a first delay time. A second feedback loop couples the output port of the first stage multiplexer to the control ports of the second stage multiplexers. This second feedback loop includes the first delay device and a second delay device having a second delay time.

Abstract: A method is used to determine information about a communication channel using an adaptive filter coupled to the channel. The adaptive filter includes adaptive filter coefficients. The filter coefficients are compared to filter coefficient thresholds. A determination is made whether one of a communication link and a channel fault exists. If a channel fault exists, a determination is made whether, i) a cable open condition exists in the channel, and ii) a cable short condition exists in the channel. An indication is made whether the channel is one of linked, open, and shorted.

Abstract: A method for establishing a virtual channel between network devices is disclosed. In the case of a local network device establishing a virtual channel with a remote network device, a virtual channel request message is sent from the local network device to the remote network device. A virtual channel acknowledgement message and a remote capability list are received and a virtual channel resume message and a local capability list are sent. The virtual channel is then enabled. In the case of a remote network device establishing a virtual channel with a local network device, a virtual channel request message is received from a local network device by a remote network device. A virtual channel acknowledgement message and a remote capability list are sent and a virtual channel resume message and a local capability list are received. The virtual channel is then enabled.

Abstract: A gain compensator compensates for the gain variation of a varactor-tuned voltage tuned oscillator (VCO) in a phase lock loop (PLL). The VCO includes a parallel LC circuit having multiple fixed capacitors that can be switched-in or switched-out of the LC circuit according to a capacitor control signal to perform band-select tuning of the VCO. The gain compensator compensates for the variable VCO gain by generating a charge pump reference current that is based on the same capacitor control signal that controls the fixed capacitors in the LC circuit. The gain compensator generates the charge pump reference current by replicating a reference scale current using unit current sources. The number of times the reference scale current is replicated is based on the fixed capacitance that is switched-in to the LC circuit and therefore the frequency band of the PLL.

Abstract: A method and apparatus for programming instruction issuing rules for instructions residing among various virtual channels, as well as the same virtual channel of an I/O bus interface for a system-on-a-chip processor. In the method and apparatus of the present invention both intra-virtual channel dependencies and inter-virtual channel dependencies are fully programmable, thereby offering significant advantages over prior art I/O interfaces. The method and apparatus of the present invention is broadly comprised of a system for managing data transactions between a first bus and a second bus. A first transaction conversion module is operably connected to the first bus and is operable to receive transactions from the first bus and a first format and to convert those transactions into an internal format.

Abstract: A Wireless Local Area Network (WLAN) supports multiple slot times. A Basic Service Set (BSS)/Independent Basic Service Set (IBSS) of the WLAN services a plurality of WLAN devices (STAs) and at least one STA of the plurality of STAs supports multiple slot times. Operation is initiated using a short slot time. Then, the a determination is made that operation of the BSS/IBSS requires use of a long slot time, wherein the long slot time is longer than the short slot time. Operation of at least one of the plurality of STAs is modified to be consistent with the long slot time. In altering the operation the STA sets a local Long Slot Termination Time (LSTT). When a Target Beacon Transition Time (TBTT) is before the local LSTT, a beacon is transmitted that indicates that the long slot time is to be used and that includes the local LSTT. When the TBTT is after the local LSTT, a beacon is transmitted that indicates that the short slot time is to be used.

Abstract: 8 PSK (Phase Shift Keying) rotationally invariant turbo trellis coded modulation without parallel transitions. A novel approach of coding 8 PSK symbols such that they are rotationally invariant employs precoding and encoding according to Turbo Trellis Coded Modulation (TTCM). Together, the preceding and TTCM encoding operate cooperatively to provide rotational invariance of the 8 PSK symbols. These 8 PSK symbols are mapped to constellation points within an 8 PSK constellation. A permutated mapping of the 8 PSK constellation is also employed that describes an approximate 90 degree rotation of the 8 PSK constellation mapping. In addition, the precoding employs an induced precoder mapping that corresponds to the approximate 90 degree rotation of the mapping of the 8 PSK constellation. Moreover, the branches of the trellis employed within the TTCM encoding may undergo an appropriately modified mapping to accommodate the 90 degree rotation of the 8 PSK constellation mapping as well.

Abstract: A digital IF demodulator receives and demodulates an analog IF input signal to produce a digital audio signal and a digital video signal. The digital IF demodulator includes an A/D converter, a first digital complex mixer, a second digital complex mixer, and various digital filters. The first digital complex mixer receives the output of the A/D converter and down-converts the output of the A/D converter to baseband. Additionally, the picture carrier is recovered from the output of the first digital complex mixer, and fed back to a direct digital synthesizer to control the tuning accuracy of the first digital complex mixer. More specifically, a feedback loop is formed to so that the picture carrier is down-converted to DC so as to control the tuning accuracy of the first digital complex mixer. The complex output of the first complex mixer is further processed using Nyquist filtering and other filtering to recover the digital video signal.

Abstract: A system and method for generating a graphical image on a display is disclosed. The graphical image is generated from data describing at least one object. The display includes a plurality of positions. Each of the plurality of positions has an area. The system and method include determining if a portion of the at least one object intersects a current position of the plurality of positions and providing an output if the portion intersects the current position. The method and system further include providing a mask for the portion if it is determined that the portion intersects the current position. The mask indicates an extent to which the at least one portion occupies the area of current position. The method and system further include utilizing the mask to provide antialiasing. The method and system also include repeating the determining, one mask providing, and utilizing steps for each of the plurality of positions.

Abstract: A host-side wireless interface services communications between a wireless user input device and a serviced host. The host-side wireless interface includes a wireless network interface, a host interface, and may include additional components. The wireless network interface wirelessly communicates with the wireless user input device. The host interface communicatively couples to the wireless interface and to the serviced host. When the serviced host initiates bootstrap operations via a Basic Input/Output System (BIOS), the host interface operates in a BIOS host interface mode to allow input from the wireless user input device to the BIOS during the bootstrap operations. Further, when the serviced host initiates Operating System (OS) operations, the host interface operates in an OS host interface mode, wherein the OS host interface mode differs from the BIOS host interface mode.

Abstract: Satellite communications are carried out using the Data Over Cable Interface Specification (DOCSIS). Satellite modems are notified of upstream channel congestion by inserting a congestion notification message in a medium access protocol (MAP) message for the upstream channel. Specifically, the congestion notification message is inserted in an unused field of the MAP message, such as the explicit congestion notification (ECN) field. The MAP message can also carry other characteristics of the upstream channel, including priority threshold, multicast access burst availability, and available bandwidth.