Abstract: In a wireless system including a wireless communication channel, a method for estimating a signal quality of a received signal includes the steps of receiving a signal from the wireless communication channel, the received signal including at least one field that is modulated and encoded in a substantially fixed manner, and generating at least one reference field based, at least in part, on the at least one field and on a channel estimation signal. The channel estimation signal is representative of at least one characteristic of the wireless communication channel. The method further includes the step of generating a signal quality estimate as a function of the at least one field in the received signal and the generated at least one reference field.

Abstract: Various embodiments of the present invention provide systems and methods for determining fly height.

Abstract: In a system comprising a plurality of processors and a memory shared by at least a subset of the processors, a method for processing video data includes the steps of: (a) a first one of the processors receiving a first video frame and storing the first video frame in the memory; (b) the first one of the processors receiving at least a second video frame, receipt of the second video frame initiating a release of the first video frame from the memory; (c) the first one of the processors sending the first and second video frames to a second one of the processors together for processing by the second one of the processors; (d) the second one of the processors generating an output video frame based at least on the first and second video frames; (e) storing the output video frame in the memory by overwriting an available memory location therein, the output video frame becoming a new first video frame; and (f) repeating steps (b) through (e) until all video frames to be processed have been received.

Abstract: Executed when a channel input (e.g., LDPC) codeword is written to a storage medium, a write-verification method (i) compares the channel input codeword to the written codeword, (ii) identifies any erroneous bits, and (iii) stores the erroneous-bit indices to a record in a table. At some later time, the written codeword is read and sent to a decoder. If the decoder fails with a near codeword, a write-error recovery process searches the table and retrieves the erroneous-bit information. The codeword bits at those indices are adjusted, and the modified codeword is submitted to further processing.

Abstract: In one embodiment, a mobile station including a chassis having a display, a power reducer, a proximity sensor, and a microprocessor. The power reducer controls power consumption of the display. The proximity sensor is coupled to the chassis and causes the power consumption to be reduced when the display is within a predetermined range of an external object. The microprocessor is coupled to the proximity sensor and to the display and automatically activates the proximity sensor based on the mobile station receiving an incoming wireless telephone call.

Abstract: Most recently accessed frames are locked in a cache memory. The most recently accessed frames are likely to be accessed by a task again in the near future and may be locked at the beginning of a task switch or interrupt to improve cache performance. The list of most recently used frames is updated as a task executes and may be embodied as a list of frame addresses or a flag associated with each frame. The list of most recently used frames may be separately maintained for each task if multiple tasks may interrupt each other. An adaptive frame unlocking mechanism is also disclosed that automatically unlocks frames that may cause a significant performance degradation for a task. The adaptive frame unlocking mechanism monitors a number of times a task experiences a frame miss and unlocks a given frame if the number of frame misses exceeds a predefined threshold.

Abstract: In accordance with the principles of the present invention utilizing the BLUETOOTH specification Cordless Telephony profile, incoming calls to a cell phone including a Gateway role can be routed to another piconet device (e.g., another cell phone including a Terminal role. Two cell phones with BLUETOOTH capability each include the Cordless Telephony Profile. The cell phone receiving the call acts as a PSTN cordless telephone Gateway cell phone via the cellular network, while the other cell phone acts as a cordless telephone Terminal cell phone. The cordless telephone Terminal cell phone then acts as an extension to the Gateway cell phone allowing both calls to the Gateway cell phone to be answered at the Terminal cell phone, and even allowing calls by the Gateway cell phone to be originated by the Terminal cell phone.

Abstract: Methods and apparatus are provided for detecting and decoding adaptive equalization training frames (having a frame marker comprised of a string of binary ones and binary zeroes). Training frames are detected by shifting the received data; inserting at least one binary value at one end of the shifted received data to generate a modified version of the received data; applying a logic function to the received data and the modified version of the received data that identifies when corresponding bit positions have different values; and detecting the frame marker when an output of the logic function has a first binary value in an approximate middle of a string of a second binary value. The training frames are decoded using a distance between the approximate center of the frame marker and a predefined binary value in an output of the logic function.

Abstract: A buffer circuit includes an input stage including at least one MOS device having a first threshold voltage associated therewith, the input stage being adapted to receive an input signal referenced to a first voltage supply. The buffer circuit further includes an output stage including at least one MOS transistor having the first threshold voltage associated therewith, an input of the output stage being connected to an output of the input stage, the output stage being operative to generate an output signal which is indicative of a logic state of the input signal. The buffer circuit includes a delay control circuit adapted for connection between at least one of the first voltage supply and a voltage return of the buffer circuit, and at least one of the input stage and the output stage. The delay control circuit includes at least one MOS device having a second threshold voltage associated therewith.

Abstract: Various embodiments of the present invention provide systems, methods and media formats for efficiently determining a position error of a head in relation to a storage medium. In one case, a system is disclosed that includes a storage medium with a series of data. The series of data includes a first defined marker and a second defined marker located a distance from the first defined marker, and position location data. The systems further include a first detector circuit that is operable to detect the first defined marker and to establish a location of the first defined marker, and a second detector circuit that is operable to detect the second defined marker and to establish a location of the second defined marker. The systems further include an error calculation circuit and an interpolation circuit. The error calculation circuit is operable to calculate an interpolation offset based at least in part on the location of the first defined marker and the location of the second defined marker.

Abstract: In one embodiment, a receiver has a reference generator and a main equalizer. The reference generator equalizes a received signal using one or more pilot reference signals. Then, the reference generator decodes one or more predetermined data channels of the equalized signal, makes hard decisions on the data of each decoded channel, and regenerates the original coding sequence of each decoded channel. The main equalizer uses each re-encoded channel as an additional reference signal along with one or more pilot signals to equalize a time-delayed version of the received signal. In alternative embodiments, the receiver might also have a step-size generator which selects optimum step sizes from a look-up table based on the number of re-encoded channels and the power of those channels. The step size is then used by the main equalizer along with the re-encoded channels to equalize the time-delayed received signal.

Abstract: In one embodiment, a buffer-based method for generating codes (such as Orthogonal Variable Spreading Factor (OVSF) codes) for spreading and despreading data, without using a chip-rate counter. First, a buffer is populated with initial values based on a received spreading factor and desired code index. Next, a timing strobe is received, and the values in the buffer are changed upon receipt of the timing strobe based on an algorithm that is independent of any count value associated with the timing strobe. Finally, a code sequence value is generated based on the values in the buffer.

Abstract: A decoder, encoder and corresponding system are disclosed for providing fast Forward Error Correcting (FEC) decoding and encoding of syndrome-based error correcting codes. Three-parallel processing is performed by elements of the system. More particularly, in an illustrative embodiment, a decoder performs three-parallel syndrome generation and error determination and calculations, and an encoder performs three-parallel encoding. Low power and complexity techniques are used to save cost and power yet provide relatively high speed encoding and decoding.

Abstract: Various embodiments of the present invention provide systems and methods for media defect detection. For example, a data transfer system is disclosed that includes a data detector, a defect detector and a gating circuit. The data detector provides a soft output, and the defect detector is operable to receive the soft output and the data signal, and to assert a defect indication based at least in part on the soft output and the data signal. The gating circuit is operable to modify the soft output of the detector whenever the defect indication is asserted.

Abstract: Methods and apparatus are provided for high-speed, low-power, high-performance channel detection. A soft-output detector is provided for processing a received signal, comprising: a forward detector for calculating forward state metrics; a backward detector for calculating backward state metrics; and a current branch detector for calculating a current branch metric, wherein at least two of the forward detector, the backward detector and the current branch detector employ trellis structures with a different number of states. A method is provided for processing a received signal using a soft-output detector, comprising: calculating forward state metrics using a forward detector; calculating backward state metrics using a backward detector; and calculating a current branch metric using a current branch detector, wherein at least two of the forward detector, the backward detector and the current branch detector employ trellis structures with a different number of states.

Abstract: The present inventions are related to systems and methods for pre-equalizer noise suppression in a data processing system. As an example, a data processing system is discussed that includes: a sample averaging circuit, a selector circuit, an equalizer circuit, and a mark detector circuit. The sample averaging circuit is operable to average corresponding data samples from at least a first read of a codeword and a second read of the codeword to yield an averaged output based at least in part on a framing signal. The selector circuit is operable to select one of the averaged output and the first read of the codeword as a selected output. The equalizer circuit is operable to equalize the selected output to yield an equalized output, and the mark detector circuit is operable to identify a location mark in the equalized output to yield the framing signal.

Abstract: Methods and apparatus are disclosed for controlling a buffer in a communication system, such as a digital audio broadcasting (DAB) communication system. A more consistent perceptual quality over time provides for a more pleasing auditory experience to a listener. The disclosed bit allocation process determines, for each frame, a distortion d[k] at which the frame is to be encoded. The distortion d[k] is determined to minimize (i) the probability for a buffer overflow, and (ii) the variation of perceived distortion over time. A buffer level is controlled by partitioning a signal into a sequence of successive frames; estimating a distortion rate for a number of frames; and selecting a distortion such that the variance of the buffer level is bounded by a specified value.

Abstract: Various embodiments of the present invention provide systems and methods for reducing low frequency loss in a magnetic storage device. For example, a data processing circuit is disclosed that includes an amplifier, two filters and a summation element. The amplifier provides an amplified output that is filtered using a first of the two filters to create a first filtered output. The first filtered output is then filtered using the second of the two filters to create a second filtered output. The summation element sums the first filtered output with the second filtered output to provide a pole altered output.

Abstract: The invention provides a single digital communication link between system-side and line-side circuitry in a DAA, capable both of carrying data signals and of transferring a substantial amount of power to the line-side circuitry. The invention comprises a system-side interface circuit, a line-side interface circuit, and an isolation barrier including a transformer. Each interface circuit is capable of connection to an upstream communication circuit (either line-side or system-side), from which it may receive data signals to be transmitted across the isolation barrier to the other interface circuit, and to which it may pass data signals received across the isolation barrier from the other interface circuit. The line-side interface circuit may further include a rectifier and a storage device.

Abstract: In one embodiment, a low cost, simple circuit for detecting an off-hook condition of a telecommunication line comprising tip and ring signal lines is provided. The circuit comprises a voltage divider for coupling between the tip and ring lines without an intervening transistor and having a node at which is presented a scaled version of a voltage across the voltage divider. The circuit further comprises a transistor having a control terminal coupled to the node, a first current flow terminal coupled to a voltage source, and a second current flow terminal coupled to an output terminal, wherein the output terminal bears a value that is indicative of a voltage across the tip and ring lines and thus whether the telecommunication line is off-hook.