Abstract: The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols.

Abstract: A system that incorporates the subject disclosure may perform, for example, a method for receiving interference information from each of the plurality of communication devices detecting interference information in a plurality of segments of a radio frequency spectrum, correlating the interference information of the plurality of communication devices to generate correlated information, and identifying a plurality of interferers according to the correlated information. Other embodiments are disclosed.

Abstract: An in-band full-duplex transceiver includes a self-interference mixer for up-converting an adjusted digital baseband signal into an up-converted self-interference cancellation signal. The adjusted digital baseband signal has a phase opposite to a phase for a leakage signal from a leakage path for the transceiver. Similarly, the adjusted digital baseband signal has a magnitude matching a magnitude for the leakage signal. Given this phasing and magnitude for the up-converted self-interference signal, it substantially cancels the leakage signal when added with a received signal contaminated by the leakage signal.

Abstract: A radio receiver device is arranged to receive a radio signal modulated with a data packet including an address portion. The radio receiver comprises: a synchronisation circuit portion arranged to produce synchronization information corresponding to the data packet; a demodulation circuit portion comprising a correlator, wherein said demodulation circuit portion is arranged to receive the radio signal and to produce an estimate of the address portion comprising a plurality of demodulated bits using said correlator and the synchronisation information; an address checking circuit portion arranged to receive the plurality of demodulated bits, to check said plurality of demodulated bits for a predetermined bit pattern, and to produce a match flag if it determines that the plurality of demodulated bits corresponds to the predetermined bit pattern.

Abstract: Disclosed is a harmonic compensation device capable of effectively reducing the harmonic distortion of an analog output signal. The harmonic compensation device includes a harmonic compensator, a mixer, a digital-to-analog converter, and an analog output circuit. The harmonic compensator is configured to generate a digital compensation signal according to a digital input signal, in which the digital compensation signal includes the harmonic components of the digital input signal. The mixer is configured to generate a digital output signal according to the digital input signal and the digital compensation signal. The digital-to-analog converter is configured to generate an analog input signal according to the digital output signal. The analog output circuit is configured to generate an analog output signal according to the analog input signal.

Abstract: Select, from transmit paths within the transmitter chip, a first transmit path for a first transmit signal and a second transmit path for a second transmit signal. The transmit paths are associated with a plurality of antenna elements of an antenna array. Determine of an added signal and/or a subtracted signal associated with the first transmit signal and the second transmit signal. Determine at least one of a first signal strength value of the added signal or a second signal strength value of the subtracted signal. Adjust a first signal parameter of the second transmit signal relative to a corresponding first signal parameter of the first transmit signal until the first signal strength value is a first value or the second signal strength value is a second value. Calibrate an offset of the corresponding first signal parameter based on the adjusted first signal parameter in the second transmit path.

Abstract: A method for processing wireless signals and a wireless device are disclosed. The method for processing wireless signals is applied to the wireless device that includes an amplifier circuit amplifying wireless signals according to a base gain. The method for processing wireless signals includes steps of: setting the base gain as a first gain value in a first operation period; performing multiple packet detections in the first operation period and counting a total number of false alarms; determining a second gain value according to the total number of false alarms; and setting the base gain as a second gain value in a second operation period that is later than the first operation period.

Abstract: Examples provide a device, an apparatus, a method, a computer program, a receiver, a mobile terminal and a base station. An interference detection device (10) is configured to generate an auxiliary interference signal for a multi-carrier receive signal. The device (10) comprises a generator (12) configured to generate a plurality of oscillator signals. The plurality of oscillator signals comprises at least a first oscillator signal with a first local oscillator frequency. The plurality of oscillator signals further comprises a second oscillator signal with a second local oscillator frequency. The device (10) further comprises a plurality of subsequent mixers. A first mixer (14) is configured to mix the multi-carrier receive signal with the first oscillator signal to output a first mixed signal. A second mixer (16) is configured to mix a second mixed signal with the second oscillator signal to output the auxiliary interference signal.

Abstract: The present invention employs a pilot scheme for frequency division multiple access (FDM) communication systems, such as single carrier FDM communication systems. A given transmit time interval will include numerous traffic symbols and two or more short pilot symbols, which are spaced apart from one another by at least one traffic symbol and will have a Fourier transform length that is less than the Fourier transform length of any given traffic symbol. Multiple transmitters will generate pilot information and modulate the pilot information onto sub-carriers of the short pilot symbols in an orthogonal manner. Each transmitter may use different sub-carriers within the time and frequency domain, which is encompassed by the short pilot symbols within the transmit time interval. Alternatively, each transmitter may uniquely encode the pilot information using a unique code division multiplexed code and modulate the encoded pilot information onto common sub-carriers of the short pilot symbols.

Abstract: A first receiver of a victim communication device may detect a first signal from an aggressor transmitter that potentially may interfere with a second signal intended to be received at a second receiver of the victim communication device. It may be determined whether the first signal interferes with the second signal based, at least in part, on the characteristics of the first signal and the second receiver. If the first signal may interfere with the second signal, the second receiver may implement reconstruction and cancelation of the interference attributable to the first signal.

Abstract: Systems, methods, apparatuses, and computer readable media are disclosed for providing interference rejection in ultra-wideband real time locating systems. In one embodiment, an ultra-wideband (UWB) receiver is configured to: receive an interference signal from a source positioned outside a monitored region; receive a composite signal transmitted from a tagged object moving about a playing field within the monitored region, wherein the composite signal comprises a location signal and a component of the interference signal; detect whether the component of the interference signal exceeds a threshold value; and adjust, via a processor, filtering of the composite signal to attenuate the component of the interference signal based on whether the component of the interference signal exceeds the threshold value. Some embodiments provide for filtering of the composite signal using a combiner while others employ a tunable notch filter.

Abstract: According to one exemplary embodiment, a communication apparatus includes: a measurement module which measures reception power of each field; a determination module which determines whether the reception power is within a range; a calculator which calculates a gain using the reception power if the reception power is not within the range; an adjuster which adjusts a field according to one of an initial gain and the calculated gain; a selector which selects a field length according to the number of field adjustments by the adjuster; and a transmitter which transmits information regarding the field length. When the number of the adjustments is lower than a first threshold value, the selector selects a first value, and when the number of the adjustments is equal to or higher than the first threshold value, the selector selects a second value that is higher than the first value, as the field length.

Abstract: An automatic gain control (AGC) method and system for a radio receiver are proposed in which the ACG comprises two AGC loops; a first loop controlling signal gain in the analog portion of the radio receiver, a second loop controlling gain in the digital domain after digitization of the received signal. The analog AGC loop has a slower response time than the digital AGC loop. When applied to a multi-branch diversity receiver, each branch has its own digital AGC loop, but the analog gain can be common to all branches, based on measurement of the analog signal in each branch.

Abstract: An adaptive stepped gain amplifier, for example for use in broadband receivers, has a step size which is dynamically compensated (for each received frequency) to cope with step error caused by frequency dependence of the amplifier performance.

Abstract: In a signal-based gain control scheme, one or more gain levels used for processing signals are selected based on characteristics of previously received signals. For example, different gain levels may be used to receive sets of signals whereupon certain characteristics of the received sets of signals are determined. One or more gain levels are then selected based on these characteristics whereby another signal is processed based on the selected gain level(s). In some aspects, the signal-based gain control scheme may be employed to facilitate two-way ranging operations between two devices. For example, leading edge detection may involve determining a characteristic of a received signal, determining a threshold based on the characteristic, and identifying a leading edge associated with the received signal based on the threshold. In some aspects, the signal-based gain control scheme may be employed in an ultra-low power pulse-based communication system (e.g., in ultra-wideband communication devices).

Abstract: A system and method for mitigating Analog to Digital (A/D) clipping is disclosed. The mean and variance of analog input data are tracked and the bits of A/D are dynamically reassigned to keep the input signal within their range. The quantization levels of A/D are dynamically re-mapped to avoid changes in sensitivity of sensor system. The method is based on random walk statistic and keeps the sensitivity of the sensor system constant. Also the system and method provides a way to mitigate A/D clipping that avoids changing the sensitivity by dynamically re-mapping the quantization levels of the A/D, keeping the sensitivity of the system constant.

Abstract: Methods and apparatus for implementing a wireless communication transceiver having receive path performance diversity. The transceiver implements a plurality of signal paths that can be configured as diversity receive paths. Each of the plurality of signal paths includes a distinct RF filter. Each RF filter can be configured to provide a distinct jammer rejection profile. Each receive path also includes a jammer detector, that can be a multiple level jammer detector. Each jammer detector operates to control a level of processing gain applied to the signals in its receive path. The multiple gain scaled receive signals can be combined in a coherent combiner before being routed for further processing.

Abstract: An integrated circuit (IC) includes an RF receiver having an AGC module that generates an automatic gain control (AGC) signal based on a strength of a received signal, and a low noise amplifier that amplifies the received signal based on the AGC signal. A processing module generates a power mode signal based on the AGC signal, the power mode signal for adjusting a power consumption parameter of the IC based on the power mode signal.

Abstract: The present invention relates to the field of communication technologies and discloses a method and an apparatus for auto gain control (AGC) in a radio receiver, which can ensure that a radio frequency device, an analog device, and various nodes in a digital domain are non-saturated and that useful signal power is adjusted to a certain power level. According to the present invention, total signal power on an air interface is subtracted from a preset first target power to obtain an analog auto gain control (AAGC) gain, and then a second target power is subtracted from an interference signal power in a digital baseband to obtain a digital auto gain control (DAGC) gain.

Abstract: Provided are a receiving apparatus and method for a wireless communication system using multiple antennas. A receiving method for a wireless communication system using multiple paths, the receiving method comprising: receiving signals through a predetermined number of multiple paths; sensing a carrier according to saturation state degrees of the signals, and providing saturation state information; calculating automatic gain components of the received signals by using the received signals and the saturation state information of the received signals; and performing a noise matching process to amplify noises on the predetermined multiple paths according to the automatic gain components during a predetermined period.

Abstract: A system, such as a transceiver, for controlling an adjustable power level includes first and second power detectors, a network of attenuators, a compensator, a comparator, and a controller. The first power detector measures the power of a signal. The network of attenuators receives the signal and generates an attenuated signal. The compensator receives the attenuated signal and generates a compensated signal. The second power detector measures the power of the compensated signal. The comparator receives the respective outputs from the first and second power detectors and generates a first error signal. The controller enables the fixed attenuation, correspondingly adjusts the variable attenuation, receives a second error signal, and provides a control signal to the network of attenuators to nullify an attenuation mismatch introduced between the fixed attenuation and the variable attenuation. A corresponding method for controlling an adjustable power level is also disclosed.

Abstract: A gain control circuit adjusts the signal level of a received signal responsive to the bandwidth a received signal and/or the delay spread of the channel in which the signal has propagated. The bandwidth and delay spread are evaluated to estimate the amount of signal variation that is expected due to fast fading. Adjustments to the signal level are then made to avoid clipping while at the same time ensuring that the dynamic range of a receiver component is efficiently utilized.

Abstract: A radio transmitting apparatus that has a plurality of antennas and changes the number of modulated signals transmitted simultaneously according to the propagation environment and so forth. A transmission power changing section 12 of a radio transmitting apparatus of the present invention adjusts the pilot symbol signal level so as to match the data symbol composite signal level according to the number of transmit modulated signals set by a modulated signal number setting section 11. By this means, the operating range of received pilot symbols and the operating range of received data symbols become approximately the same on the receiving side, enabling pilot symbol quantization error to be reduced. As a result, the precision of radio wave propagation environment estimation, time synchronization, and frequency offset estimation using pilot symbols improves, and consequently data reception quality improves.

Abstract: The present invention discloses a method for implementing automatic frequency control, and an apparatus thereof. The method discloses: calculating a correlation value of common pilot symbols in a reception signal of each path and a frequency offset value, calculating a combined frequency offset value according to the frequency offset value of each path, and determining, according to the combined frequency offset value, a frequency offset adjustment value for a voltage controlled oscillator, a frequency offset adjustment value for overall reception signals and a frequency offset adjustment value for the reception signal of each path. The present invention selects a method of small-scope frequency offset estimation, which makes frequency offset estimation more accurate.

Abstract: An FM receiver includes a receiving unit that receives a signal from a broadcasting station and outputs a receiving signal, an equalizer that equalizes the receiving signal by using a calculated weight, and obtains an equalized output signal, a demodulator that demodulates the equalized output signal to reproduce the signal from the broadcasting station, a detection unit that observes size of the calculated weight to detect a capture state with respect to an undesired broadcasting station and generates a capture detection signal, and a weight setting unit that sets the calculated weight with respect to the equalizer at a steady state, and sets a specific weight for temporarily setting the equalizer in a through state when the capture detection signal is generated.

Abstract: Aspects of a method and system for channel estimation in a MIMO communication system with multiple RF chains for WCDMA/HSDPA may comprise receiving a plurality of communication signals from a plurality of transmit antennas. A plurality of vectors of baseband combined channel estimates may be generated based on phase rotation of the received plurality of communication signals. A matrix of processed baseband combined channel estimates may be generated based on the generated plurality of vectors of baseband combined channel estimates. A plurality of amplitude and phase correction signals may be generated based on the generated plurality of vectors of baseband combined channel estimates. An amplitude and a phase of at least a portion of the received plurality of communication signals may be adjusted based on the generated plurality of amplitude and phase correction signals, respectively.

Abstract: According to one embodiment, a receiving apparatus includes a variable gain amplifier, comparator, and signal processor. The comparator compares a signal level of the second signal with a first threshold to generate a third signal, a signal level of the third signal being set to a high signal if the signal level of the second signal is greater than the first threshold. The signal processor determines presence of a signal if a rate of high signals in third signals for a period is greater than a second threshold. The second threshold is set to a first value when the control of the gain is performed and set to a second value when the demodulation processing is performed. The first value is greater than the second value.

Abstract: A transconductance comparator includes a comparator having an output of a detector configured to sense an amplitude of an output of a Variable Gain Amplifier (VGA) of a receiver as a first input and a reference amplitude level as a second input. The comparator generates an error signal based on the first input and the second input. The transconductance comparator also includes a transconductance amplifier having a differential voltage input based on the error signal generated through the comparator and generating an output current. The transconductance amplifier includes current sources associated with programmable current limits thereof and differential pairs associated with the current sources, one or more of which is implemented with a size mismatch between transistors thereof to eliminate an offset error due to a mismatch between the current limits, thereby enabling programmability of an attack time and a decay time during automatic gain control of the VGA.

Abstract: Systems and methods for distributed antenna system reverse path summation using signal-to-noise ratio optimization are provided. In one embodiment, a method for reverse path summation for a distributed antenna system comprises: normalizing an uplink noise floor for a plurality of remote antenna units of a distributed antenna system, wherein the uplink noise floor is normalized based on a first remote antenna unit having a lowest noise floor of the plurality of remote antenna units; and scaling an uplink output gain of each of the plurality of remote antenna units by a scaling factor, wherein the scaling factor attenuates the uplink output gain based on a composite maximum host peak power for a host unit coupled to the plurality of remote antenna units.

Abstract: An audio output controlling apparatus and method, and a mobile terminal system using the same control settings of an audio out port according to whether an audio frame includes an audio signal. The audio output controlling method includes receiving an audio frame, determining whether an audio signal is included in the audio frame, and setting, depending on whether the audio signal is included in the audio frame, a power voltage provided to an audio out port. The mobile terminal includes a wireless transceiver; an audio unit, through an audio out port, an audio frame among the wireless data; and an audio output controlling unit to control a power voltage of the audio out port. The apparatus includes a section determining unit; and a power controlling unit to set a power voltage provided to an audio out port according to whether the audio signal is included in the audio frame.

Abstract: A distributed architecture system for receiving radio frequency (RF) signals includes a receiving unit receiving a plurality of RF signals. The receiving unit includes means for combining the plurality of RF signals into a multiplexed signal. A head unit receives and separates the multiplexed signal into a plurality of information signals. The head unit prepares the information signals for presentation to a user. The head unit is disposed remotely from the receiving unit. A multiplexed link carries the multiplexed signal from the receiving unit to the head unit.

Abstract: A system for distinguishing between any one of a plurality of antennas in a multiple-input-multiple-output (MIMO) system having an augmented number of antennas is provided herein. The system includes a MIMO receiving system having N branches and configured to operate in accordance with a channel estimation MIMO receiving scheme; a radio distribution network (RDN) connected to the MIMO receiving system, the RDN comprising at least one beamformer, being fed by two or more antennas, so that a total number of antennas in the system is M, wherein M is greater than N, wherein each one of the beamformers include a combiner configured to combine signals coming from the antennas into a single signal; and at least one antenna distinguishing circuitry, each associated with a respective beamformer, wherein the antenna distinguishing circuitry is configured to distinguish between the signals coming from the antennas which feed the respective beamformer.

Abstract: A transmitter, a base station device, and a method for aligning a signal output from a transmitter are provided. The transmitter is connected to a first antenna, and the first antenna detects a second test signal transmitted by a second antenna that is connected to another transmitter. The transmitter includes: a signal generating unit, which generates a first test signal; a directional coupler, which receives the first test signal and the second test signal; and a signal processing unit, which measures a timing difference between the first test signal and the second test signal, and uses the measured timing difference to control signal generation, so as to align a signal transmission delay between the two transmitters. Thus, closed-loop detection and an adaptive rectification mechanism for transmission signals of multiple transmitters can be implemented, and accuracy of aligning a signal at each transmitting antenna is improved.

Abstract: A radio receiver includes a plurality of receiver signal strength indicator (RSSI) circuits coupled to respective output taps of various gain stages along the receiver chain. Each of the RSSI circuits generates a respective 1-bit clip information signal. A processor accumulates the clip information signals to estimate the signal strength of an inbound RF signal and sets a gain of the radio receiver based on the estimated signal strength.

Abstract: A receiver includes a first mixer configured to provide an in-phase (I) component of a radio frequency (RF) signal to an I channel by down-converting the RF signal, a second mixer configured to provide a quadrature (Q) component of the RF signal to a Q channel by down-converting the RF signal, amplification means, arranged on the I and Q channels, configured to amplify the I and Q components, a mismatch estimator configured to convert the amplified I and Q components into a frequency domain, and estimate a gain mismatch value and a phase mismatch value on the basis of the converted components, and a mismatch compensator configured to compensate for mismatch of the received signal on the basis of the estimated gain and phase mismatch values.

Abstract: A transmission apparatus in a Multiple Input Multiple Output (MIMO)-based wireless communication system. The transmission apparatus includes at least two antenna groups each having at least two antennas, wherein the antenna groups are spaced apart by a first distance and transmit antennas in each antenna group are spaced apart by a second distance which is shorter than the first distance. A channel coding and modulation unit channel-codes and modulates a desired transmission data stream. A precoding unit precodes the channel-coded and modulated signal separately for each antenna group and each antenna in the same antenna group. Thereafter, a transmission processing unit transmission-processes the output signal from the precoding unit.

Abstract: The present invention discloses an apparatus and method for power-saving switch on a pair of configurable analog-to-digital converters. The apparatus mainly comprises an antenna, an antenna switch, a zero-IF RF receiver, and a baseband demodulator. By using a first and a second control signal to control the ON/OFF states of a plurality of switches and a plurality of stage units in the configurable analog-to-digital converters, and the third control signal to control the ON/OFF states of a plurality of LNA stages and the gain of a plurality VGAs, the power saving of the analog-to-digital converter is easily achieved.

Abstract: A signal processing device includes a device package, processing circuitry and biasing circuitry. The processing circuitry is packaged in the device package and is operative to receive one or more Radio Frequency (RF) input signals from one or more antenna elements via one or more pre-amplifiers that are separate from the device, and to process the RF input signals so as to produce an RF output signal. The biasing circuitry is packaged in the device package and is operative to produce one or more biasing signals for biasing the pre-amplifiers.

Abstract: A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine.

Abstract: Disclosed is a radio frequency (RF) receiver for receiving a communication channel modulated on one or more carrier frequencies. The receiver may include a gain adjustable RF amplifier, a wideband signal power measurement circuit, and control logic. The control logic may be adapted to use outputs of one or more measurement circuits to classify interfering signals based on measured signal power and spectral proximity to the one or more channel carrier frequencies, and to adjust the gain of the radio frequency amplifier based on the classification.

Abstract: Systems and methods for distributed antenna system reverse path summation using signal-to-noise ratio optimization are provided. In one embodiment, a method for reverse path summation for a distributed antenna system comprises: normalizing an uplink noise floor for a plurality of remote antenna units of a distributed antenna system, wherein the uplink noise floor is normalized based on a first remote antenna unit having a lowest noise floor of the plurality of remote antenna units; and scaling an uplink output gain of each of the plurality of remote antenna units by a scaling factor, wherein the scaling factor attenuates the uplink output gain based on a composite maximum host peak power for a host unit coupled to the plurality of remote antenna units.

Abstract: The invention teaches a solution, for example, for Long Term Evolution (LTE) networks. The solution comprises determining a measurement pattern for at least one automatic gain control tracking loop when resource restrictions have been configured for a user equipment, the resource restrictions comprising at least one measurement restriction pattern, wherein each automatic gain control tracking loop is associated with at least one measurement restriction pattern; and performing automatic gain control measurements according to the measurement patterns of the at least one automatic gain control tracking loop.

Abstract: An automatic gain control circuit is described including a state machine controller for adjusting intermediate frequency gain and radio frequency gain and a baseband demodulator, wherein the baseband demodulator receives information from the state machine controller regarding status of the state machine controller and further wherein the state machine controller receives correlation information from the baseband demodulator. Also described is a method including detecting a signal, providing state machine controller information to a baseband demodulator, reducing a radio frequency gain, reducing an intermediate frequency gain and receiving correlation information from the baseband demodulator.

Abstract: A method for transmitting symbols in a communication system, includes dividing N symbols to be transmitted at one time into 2 groups. A first processing is performed on each of a plurality of symbols in a first group in order to obtain a first group of superimposed symbols. A second processing is performed on each of a plurality of symbols in a second group to obtain a second group of superimposed symbols. Each of the first group of superimposed symbols is transmitted one by one by a first antenna, and corresponding symbols in the second group of superimposed symbols are transmitted by a second antenna. The first processing and the second processing respectively include a conjugate cancellation operation.

Abstract: Aspects of a method and system for channel estimation in a MIMO communication system with multiple RF chains for WCDMA/HSDPA may comprise receiving a plurality of communication signals from a plurality of transmit antennas. A plurality of vectors of baseband combined channel estimates may be generated based on phase rotation of the received plurality of communication signals. A matrix of processed baseband combined channel estimates may be generated based on the generated plurality of vectors of baseband combined channel estimates. A plurality of amplitude and phase correction signals may be generated based on the generated plurality of vectors of baseband combined channel estimates. An amplitude and a phase of at least a portion of the received plurality of communication signals may be adjusted based on the generated plurality of amplitude and phase correction signals, respectively.

Abstract: Circuits, architectures, a system and methods for providing on-chip gain calibration. The circuit generally includes a receiver comprising (i) a resistor on a semiconductor substrate, the resistor configured to provide a signal having a noise component that varies with temperature, and (ii) an amplifier circuit on the semiconductor substrate coupled to the resistor, the amplifier circuit configured to receive the signal and provide a second signal having an amplitude greater than the first signal. The architectures and/or systems generally include those that embody one or more of the inventive concepts disclosed herein. The method generally includes (i) providing a noise signal from a resistor to an amplifier, the resistor being on a common semiconductor substrate with the amplifier, (ii) determining a resistance value of the resistor, (iii) determining an impedance at an input of the amplifier, and (iv) determining a gain of the amplifier.

Abstract: An antenna system for receiving an RF signal from a first antenna and a second antenna includes a phase shift circuit. The phase shift circuit shifts a phase of the RF signal from the second antenna by one of a plurality of possible phase shifts to produce a phase shifted signal. A combiner combines the RF signal from the first antenna and the phase shifted signal to produce a combined signal. A comparator circuit compares a signal quality of the combined signal with a minimum threshold value to determine if the signal quality of the combined signal is equal to or greater than the threshold value. The comparator circuit is in communicative control of the phase shift circuit and maintains the phase shift of the RF signal received by the second antenna in response to the signal quality of the combined signal being equal to or greater than the threshold value.

Abstract: According to an embodiment, a DC offset canceller includes a first DA converter, a first adder, an amplifier, a comparator, an averaging circuit, and a successive approximation register. The first DA converter is configured to DA-convert first correction data into a first correction voltage. The first adder is configured to add an input signal and the first correction voltage to output a first added signal. The amplifier is configured to amplify the first added signal to output an amplified signal. The comparator is configured to compare the amplified signal and a reference voltage to output a comparison result. The averaging circuit is configured to receive the comparison results of the comparator to obtain a majority decision result by performing majority decision on logical values of the comparison results in a predetermined time period.

Abstract: A radio transmitting apparatus that has a plurality of antennas and changes the number of modulated signals transmitted simultaneously according to the propagation environment and so forth. A transmission power changing section 12 of a radio transmitting apparatus of the present invention adjusts the pilot symbol signal level so as to match the data symbol composite signal level according to the number of transmit modulated signals set by a modulated signal number setting section 11. By this means, the operating range of received pilot symbols and the operating range of received data symbols become approximately the same on the receiving side, enabling pilot symbol quantization error to be reduced. As a result, the precision of radio wave propagation environment estimation, time synchronization, and frequency offset estimation using pilot symbols improves, and consequently data reception quality improves.

Abstract: An apparatus and method for receiving and processing multiple independent, uncorrelated RF signals is presented. The apparatus includes a Hybrid-Direct Conversion Receiver incorporating front end branches, protocol-specific digital processing branches, an interference detector, a correlator, and an offset control for controlling oscillator sources. The front end branches each contain a preselector that filters received signals and a mixer that down converts the received signal to an IF offset from a reference frequency by a unique offset. The bandwidth of an IF processor is partitioned into sub-channels corresponding to the different offsets and is wider than the combination of the sub-channels. The interference detector and correlator determine whether a particular desired signal is degraded by interference signals and select a new sub-channel. This information is provided to the offset control, which adjusts a LO source coupled to the corresponding down mixer accordingly.