Abstract: The present invention discloses a method for de-spreading quadrature pseudorandom noise, which including: inputting data sequences I? and Q?, and inputting pseudorandom noise sequences PNI and PNQ, on which quadrature pseudorandom noise de-spreading operation will be performed; in each timeslot, extracting continuously 2048 codeword from each pseudorandom noise sequence PNI and each pseudorandom noise sequence PNQ respectively, performing time-division de-multiplexing operation on the 2048 codeword respectively, and obtaining pseudorandom noise sequences PNI? and PNQ? both with a length of 1600 codeword; performing quadrature pseudorandom noise de-spreading operation on the pseudorandom noise sequences PNI? and PNQ? and the data sequences I? and Q? with a length of 1600 codeword input in the timeslot, and then outputting data sequences I and Q. The invention operates the input sequences to be performed with quadrature PN de-spreading.

Abstract: An apparatus includes a plurality of antennas, where each antenna is configured to receive wireless signals transmitted using adaptive beam forming. The apparatus also includes a plurality of wireless radios, where each wireless radio is configured to output signals representing the wireless signals received by one of the antennas. The apparatus further includes a plurality of first diversity combiner units, where each first diversity combiner unit is configured to perform spread spectrum diversity combining using the signals output by one of the wireless radios. In addition, the apparatus includes a second diversity combiner unit configured to perform antenna diversity combining using signals output by the first diversity combiner units, where the second diversity combiner unit is configured to output recovered wireless signals.

Abstract: A cable modem includes a subscriber line interface circuit (SLIC) that is connected to a telephone. The cable modem can send a signal to the telephone through the SLIC, and detect signal reflection of the telephone in the SLIC. The cable modem measures frequencies of the signal reflection and the output of the telephone. The cable modem also compares the measured frequencies with corresponding thresholds and self-determines to be qualified or unqualified, based upon the comparisons.

Abstract: A low offset input circuit and a signal transmission system which can accommodate a high-speed interface and achieve reduction of an offset voltage are provided. An offset voltage compensating circuit block 103 having an input circuit block 108 including an input circuit 104 and an adder-subtractor circuit block 105, switches 108, 109, a detecting circuit block 106, and an adjusting and holding circuit block 107 is provided. To compensate for an offset voltage of the input circuit block 102, an offset voltage of the input circuit block 102 is detected at the detecting circuit block 106 by turning on the switches 108, 109, and the detected offset voltage is held in the adjusting and holding circuit block 107, and negative feedback of the held offset voltage to the adder-subtractor circuit block 105 is performed. Thereby, signals Vop, Von having compensated offset voltages are outputted from the input circuit block 102.

Abstract: The present invention provides a technique for reducing power levels associated with two or more input signals using peak reduction distortion that is derived from a combined signal, which represents a combination of the input signals.

Abstract: Methods for code-division multiplex communications. The method involve generating orthogonal or statistically orthogonal chaotic spreading codes (CSC1, . . . , CSCK) having different static offsets using a set of polynomial equations (f0(x(nT)), . . . , fN-1(x(nT)) and/or f0[x((n+v)T+t)], . . . , fN-1[x((n+v)T+t)]). The methods also involve forming spread spectrum communications signals respectively using the orthogonal or statistically orthogonal chaotic spreading codes. The methods further involve concurrently transmitting the spread spectrum communications signals over a common RF frequency band. The spreading codes are generated using different initial values for a variable “x” of a polynomial equation f(x(nT)) and/or different acc-dec values for a variable “v” of a polynomial equation f[x((n+v)T+t)]. The static offsets are defined by the different initial values for a variable “x” and/or different acc-dec values for a variable “v”.

Abstract: An equalizer based receiver operation method and apparatus in a mobile communication system are provided. The method includes estimating a channel for a multi path receive signal, analyzing a delay profile of a multi path channel, and selecting a tap position from a plurality of tap positions of an equalizer depending on the analyzed delay profile.

Abstract: Disclosed are methods and systems for filtering an intermediate frequency (IF) band when digitizing a radio frequency (RF) signal using a higher Nyquist zone several times above the sampling rate. Undersampling may be employed along with an undersampled Nyquist filtering technique to implement an integrated receiver for base station applications such as wireless base station beacon monitoring. Such a receiver may be integrated into a smaller package and consume less power at a reduced cost. In one embodiment, the receiver may operate at a high RF sampled frequency that is microsampled in the 10th Nyquist zone at less than 20% undersampling. In another embodiment, the receiver may operate in the 5th Nyquist zone at ½ the sampling rate with 40% undersampling. In various embodiments, sampling and processing functions may be implemented using software on a computer or other embedded computing device.

Abstract: What is disclosed is a method of operating a communication system. The method includes receiving a request to initiate a communication session with a wireless communication device, wherein the request indicates an application type. The method also includes determining a spreading code based on the application type, and transferring the spreading code to the wireless communication device. The method also includes receiving communications for the communication session encoded with the spreading code and decoding the encoded communications based on the spreading code.

Abstract: A DMB-T receiver supports a single carrier (SC) form of modulation and a multi-carrier form of modulation such as orthogonal frequency division multiplexing (OFDM). Upon receiving a broadcast signal, the DMB-T receiver downconverts the received broadcast signal to a received base-band signal and determines a frame number for each frame by correlating groups of the received symbols in adjacent signal frames. In particular, the receiver determines a maximum right-shift correlation value and a maximum left-shift correlation value. If the magnitude of the maximum right-shift correlation value is greater than, or equal to, the magnitude of the maximum left-shift correlation value, then the maximum right shift correlation value is used to retrieve a frame number from a look-up table. Otherwise, the negative value of the maximum left-shift correlation value is used to retrieve a frame number from the look-up table.

Abstract: According to some embodiments, a digital switching distortion canceller may receive Ethernet data along with an Ethernet class AB transceiver switching signal. A combiner may combine the output of the digital switching distortion canceller with a digital high switching distortion signal to generate a corrected output signal. According to other embodiments, a switching-signal-to-voltage-converter receives an Ethernet class AB transceiver switching signal and generates a common-mode compensation voltage adjustment. An analog combiner may combine the common-mode compensation voltage adjustment with a noisy common-mode signal to generate a stabilized common-mode voltage. Note that reduction of switching-related distortion might be achieved in the digital domain, in the analog domain, or in both domains according to the embodiments described herein.

Abstract: A micro-controller to perform the FSK (HART) modem functions as well as communications and control functions in an isolated channel implementation is described. In one embodiment, the micro-controller comprises: a processor, an analog-to-digital converter configured to transform received analog signals into digital values at a predetermined digital sample rate; and a memory unit containing a set of computer-executable instructions that, when executed on the processor, provide a built-in FSK bi-directional modem function that converts the received digital values into binary signals. The FSK (HART) demodulation function is performed by the micro-controller with the built-in FSK modem function in three sequential phases implemented in computer code: (1) zero crossing and amplitude detection; (2) bit stream and timing generation, and (3) character generation and bit synchronization.

Abstract: The present invention relates to a transmission method and device suitable for a system using Nt transmit antennas TXi and Nr receive antennas RXj. The symbols transmitted are inserted in a time-frequency frame that contains a training sequence. Each training sequence is constructed from replicas of a basic training sequence. At least one of the training sequences includes at least two replicas at least one of which is phase offset.

Abstract: Disclosed herein is a phase noise limiting apparatus including a detection section configured to detect a phase noise quantity from an input signal; a determination section configured such that furnished with a plurality of correspondence tables indicating parameters used for phase synchronization with the input signal, the determination section determines one of the parameters in keeping with the phase noise quantity detected by the detection section on the basis of one of the plurality of correspondence tables; and a phase noise limitation section configured to limit the phase noise in the input signal based on the parameter determined by the determination section.

Abstract: A system, device and method are described for suppressing certain sub-carrier frequencies within a multi-path transmission system and efficiently notifying a receiver (400) of the suppressed sub-carriers. In various embodiments of the invention, an OFDM system uses the preamble (210) of an OFDM burst for indicating which sub-carrier frequencies are being suppressed by a transmitter (300).

Abstract: In a method for estimating a signal-to-noise ratio (SNR) of an orthogonal frequency division multiplexing (OFDM) wireless mobile communication system, noise is estimated from adjacent received signals of at least two adjacent subcarriers and received signals of subcarriers, noise power is calculated by calculating a mean square value of the estimated noise by summing squares of the estimated noise, a mean square value of the received signals is calculated by summing squares of the received signals, signal power is calculated by subtracting the noise power from the mean square value of the received signals, and the SNR is calculated using the signal power and the noise power. Thus, the method of the present invention having low complexity can estimate an SNR efficiently regardless of channel changes on a frequency axis when one OFDM symbol includes preamble data.

Abstract: A method of implementing a low jitter and high bandwidth clock and data recovery (CDR) apparatus includes acquiring early, optimal, and late votes; determining which votes are allowed and weighted; disallowing votes not determined to as allowed; weighing votes, wherein votes that would make the CDR move to an extreme of a zero crossing are weighted less; and accumulating votes and adjusting a recovered clock phase based on the accumulated votes. A computer readable medium storing instructions to implement a low jitter and high bandwidth CDR apparatus, the instructions includes functionality to: acquiring early, optimal, and late votes; determining which votes are allowed and weighted; disallowing votes not determined to as allowed; weighing votes, wherein votes that would make the CDR move to an extreme of a zero crossing are weighted less; and accumulating votes and adjust recovered clock phase.

Abstract: This invention provides a transmission architecture of transmitter which includes a forestage module, a pilot insertion, a scramble selector, and a backstage module. A frequency domain data symbol is transmitted by the forestage module. A pilot signal is inserted in the frequency domain data symbol by the pilot insertion, and a frequency domain pilot symbol is produced. The frequency domain pilot symbol performed a scramble operation and a select operation with certain scramble patterns by the scramble selector, and a requirement symbol is produced. The requirement symbol is converted into the transmitted signal by the backstage module. Because the use of the scramble operation and the select operation from the scramble selector, the transmission architecture of transmitter provided by this invention can both reduce the PAPR and increase the multi-cell diversity gain in an OFDM single frequency network system.

Abstract: A communication system includes first and second independently clocked devices, comprising, for each device, a transmitter and a receiver connected to each other in a crossed way in correspondence of an inter-chip communication channel. The communication system further comprises a synchronizer in turn including at least a first and a second synchronization block, having respective input terminals connected to the receivers and respective output terminals connected to the transmitters and comprising at least: a test pattern generator that generates a programmable test pattern signal; a pattern detector to check a matching between stored and received test pattern signals and thus lock corresponding clock phases of the synchronization blocks in case of positive result of this check; and a delay block able to change the clock phases until a synchronized condition of the synchronization blocks is verified, this synchronized condition corresponding to a matching between stored and received test pattern signals.

Abstract: A system and method are provided for zeroing pre and post-tap settings in a link partner using a plurality of voltage gain taps. The method provides a link partner (LP) transmitter. A network-connected local device (LD) selects an LP pre-tap or post-tap. The LD also chooses a zero gain setting for the selected LP tap. In a first iteration, the LD directs the LP to decrease the difference between the selected tap gain setting and the zero setting by 1 step. If a limit signal is not received by the LD, the LP is directed to maximally increase the center tap gain setting until a limit signal is received. The iterations are continued until a limit signal is returned in response to the LD directing the LP to decrease the difference between the selected tap gain setting and the zero setting.