Abstract: The application discloses a transceiver, including a calibration signal generation unit, a transmission unit, a receiving unit and a control unit. The calibration signal generation unit generates test signal to the transmission unit in a phase calibration mode. The receiving unit generates a digital receiving signal. The control unit calculates a phase difference between the digital receiving signal and a given reference phase and selectively adjust the transmission unit or the receiving unit accordingly. The application discloses a transceiver calibration method as well.

Abstract: An example method includes detecting an event in an electronic system. The electronic system includes an electronic component and a switched mode power supply. The electronic component draws an amount of power from the switched mode power supply during operation. In response to detecting the event, the electronic component is operated to cause the electronic component to change the amount of power that the electronic component draws from the switched mode power supply. The change in the amount of power that the electronic component draws causes the switched mode power supply to output a signal that is evidence of the event.

Abstract: A direct current (DC) offset protection circuit includes: a DC offset detection circuit and a control circuit. The DC offset detection circuit is arranged to detect whether a DC component exists in pulse-width-modulation (PWM) signals and accordingly generate a DC offset detection result. The control circuit is arranged to control an audio system according to the DC offset detection result. The DC offset detection circuit comprises a PWM polarity judgment circuit, a cascaded integrator-comb (CIC) filter and a DC offset judgment circuit. The PWM polarity judgment circuit is arranged to judge a polarity of complementary PWM signals and accordingly generate a polarity indication value. The CIC filter is arranged to generate a filter output signal by averaging a plurality of polarity indication values. The DC offset judgment circuit is arranged to generate the DC offset detection result by comparing the filter output signal with a predetermined DC threshold.

Abstract: The application discloses a transceiver and a transceiver calibration method. The transceiver includes: a calibration signal generation unit for generating a first test signal and a second test signal to a transmission unit in a gain calibration mode; the transmission unit for generating a combined signal according to the first test signal, the second test signal and a transmission gain; a mixer for performing self-mixing upon the combined signal to generate a self-mixed signal; a receiving unit for generating a receiving signal according to the self-mixed signal; a Fourier transformer for computing a power of the receiving signal at a specific frequency; and a gain calibration unit for adjusting the transmission gain according to the power at the specific frequency in the gain calibration mode.

Abstract: A ramp signal generating method and a generator thereof, and a pulse width modulation signal generator are provided. The ramp signal generating method includes following steps: receiving an error signal, wherein the error signal relates to an output voltage of a power converter; generating an error delayed signal according to the error signal; and providing a ramp signal according to the error signal and the error delayed signal. The ramp signal is phase leading and inverting compared to the error signal. The ramp signal serves to improve a response speed of the power converter.

Abstract: A single tone RF signal generator and a method of generating a single tone RF signal. The single tone RF signal generator includes an output and a power amplifier that has an input. The power amplifier is operable to receive an RF signal including a first harmonic corresponding to a single tone signal to be produced by the signal generator. The power amplifier is also operable to amplify the RF signal. The power amplifier is further operable to provide the amplified RF signal to the output of the signal generator. The single tone RF signal generator further includes a feedback circuit connected between the output of the signal generator and the input of the power amplifier. The feedback circuit is configured to add one or more predistortion harmonics to the RF signal received by the power amplifier for cancelling harmonics in the amplified RF signal provided by the power amplifier.

Abstract: Various embodiments of communication systems and methods in which the communication system is operative to find, record, and use sets of pre-distortion parameters in conjunction with a pre-distortion procedure, in which each set of pre-distortion parameters is operative to specifically counter distortions produced in a power amplifier by a specific combination of level of input signal power and level of analog gain associated with a transmission path of the communication system. In some embodiments, there is a modulator, a transmission chain, a distortion analysis mechanism, and a pre-distortion mechanism, operative to analyze and modify signals so as to counter signal distortion.

Abstract: A modulation circuit includes a digital quantizer and a compensation circuit. The digital quantizer is utilized to receive and truncate a digital quantizing input signal for generating a digital quantizing output signal. The compensation circuit compensates for a time delay of the modulation circuit and generates a compensation output signal. The digital quantizing input signal is generated by subtracting the compensation output signal from a digital integration output signal to compensate for the time delay before truncating the digital quantizing input signal.

Abstract: An annular time-to-digital converter includes a pulse shaper that shapes an input start pulse and an input stop pulse to form fixed-width pulses for output. The annular time-to-digital converter also includes at least two differential comparing units that enable, during matching enabling, triggers of the differential comparing units to set setting ends to 1. A circle counter counts the number of times a pulse is propagated in a loop. A matching enabling logical device generates a matching enabling signal, and sends the generated matching enabling signal to comparing enabling ports of the differential comparing units. At least two in-loop position encoders find a position of a first matched unit according to matching signals sent by the differential comparing units. Result recording registers record the number of circles and in-loop positions when matching occurs. High resolution is realized using a differential chain, and wafer area is saved by the annular design.

Abstract: The present invention relates to a switched-mode power supply apparatus and a corresponding method. For an effective compensation of non-linearities caused by dead-time and voltage drops in the switching power amplifier of the apparatus, an apparatus is proposed comprising a switching power amplifier (14) for amplifying a signal supplied by an external signal source (11) and for supplying a load voltage and/or load current to a load (15), and a control unit (12; 12b) for controlling the switching of said switching power amplifier based on a timing setting, said control unit being adapted for simulating the behavior of the switching power amplifier by predicting the average load voltage and/or load current for at least two, in particular a plurality of, timing settings for a desired load voltage and/or load current based on state information about the present state of the switching power amplifier.

Abstract: A method for modifying a characteristic of a representation of a complex-valued signal which comprises at least a representation of a first and a second complex-valued symbol comprising deriving a relative phase angle between the representation of the first and the second complex-valued symbols. The method further comprises combining a representation of a complex-valued enhancement pulse and the representation of the complex-valued signal to obtain a representation of a first and a second corrected complex-valued symbol, wherein the enhancement pulse is chosen such that the relative phase angle between the first and second corrected symbols is smaller than a predetermined threshold.

Abstract: A multi-band signal is generated by combining two or more input signals separated in frequency. The input signals are combined either before or after predistortion depending on the bandwidth of the multi-band signal. If the bandwidth of the multi-band signal is less than a predetermined bandwidth threshold, the input signals are combined and predistortion is applied to the combined signal to generate the multi-band signal. If the bandwidth of the multi-band signal is greater than the bandwidth threshold, the individual input signals are predistorted and subsequently combined to generate the multi-band signal.

Abstract: A method and apparatus for encoding feedback signal is provided. The method includes: encoding feedback signals of three carriers to output a bit sequence; and transmitting the bit sequence on a High Speed-Dedicated Physical Control Channel (HS-DPCCH). The encoding the feedback signals of the three carriers may specifically include: mapping the feedback signals of the three carriers into a codeword, in which the codeword can be selected from a codebook, and codewords in the codebook satisfy a particular code distance relationship. The method for jointly encoding feedback signals of three carriers in a Ternary Cell (TC) mode is provided. Feedback signals are transmitted over a single code channel. Therefore, power overhead is reduced, and system performance is improved.

Abstract: A communications device includes a modulator and a filter downstream therefrom and operable to generate an output wideband complex signal with a frequency notch therein. The filter includes a finite impulse response (FIR) filter with L taps to generate N output values, with L>N. A Fast Fourier Transform (FFT) block is downstream from the FIR filter and has a length N so that filter transition regions occur between frequency bins of the FFT block. A notching block is downstream from the FFT block to generate the frequency notch. An Inverse Fast Fourier Transform (IFFT) block is downstream from the notching block and has the length N.

Abstract: An apparatus and method for amplifying a Transmit (Tx) signal according to an Envelope Tacking (ET) scheme in a wireless communication system are provided. A transmitting end apparatus includes an envelope gain controller for controlling a gain of a digital baseband Tx signal in accordance with power control, a detector for detecting an envelope signal from the digital baseband Tx signal whose gain is controlled, and for shaping on the envelope signal, a first Digital to Analog Converter (DAC) for converting the shaped envelope signal into an analog signal, and an envelope modulator for generating a drain bias of a power amplifier that amplifies a Radio Frequency (RF) Tx signal by using the analog envelope signal. Accordingly, a digital-based ET scheme is implemented, and by using a plurality of shaping tables, efficiency of the ET scheme can be maximized in a transmitting end that uses power control.

Abstract: A triangular wave generator in a pulse width modulation signal generator to generate a triangular wave signal and a pair of pulse signals. The first pulse signal is pulsed for a given duration of time when the triangular wave signal reaches a minimum limit thereof. The second pulse signal is pulsed for a given duration of time when the triangular wave signal reaches a maximum limit thereof. The voltage comparator generates a first pulse width modulation signal by comparing the triangular wave signal with an externally supplied direct current signal. The wave shaping circuit generates a second pulse width modulation signal by removing chattering components occurring immediately after rising and falling edges of the first pulse width modulation signal with a masking signal generated based on the first and second pulse signals and the first pulse width modulation signal.

Abstract: A pulse width modulation method for controlling the output power of a pulsed gas discharge laser powered by a pulsed RF power supply comprises delivering a train of digital pulses to the RF power supply. Each pulse in the train has an incrementally variable duration. The power supply is arranged to deliver a train of RF pulses corresponding in number and duration to the train of digital pulses received. The average power in the RF-pulse train can be varied by incrementally varying the duration of one or more of the digital pulses in the digital pulse train. The train of RF pulses is used to power a gas discharge laser. The gas discharge laser outputs a pulse train corresponding to the RF pulse train.

Abstract: A wireless network (20) with at least a first radio communication unit (24) and a second radio communication unit (26) transmits and receives signals with minimal interference from the surrounding environment of the first unit (24) and second unit (26). The first radio communication unit (24) determines frequencies (54) having power level above a threshold (52), and creates a list of these frequencies (50) to be transmitted to the second radio communication unit (26). The second radio communication unit (26) places notches (140) in its transmission band (88) based on frequencies (54) in the list (50), reserved frequencies (132), and local frequencies (92) having signal energy above a threshold (90). When transmitting a signal (42), the second radio communication unit (26) avoids transmitting in frequencies that have notches (140).

Abstract: In a particular embodiment, a circuit device is disclosed that includes a data generator adapted to output a random pulse sequence having a particular spectral shape. The circuit device further includes a pulse edge control circuit to selectively apply a carrier suppression operation to at least one pulse-width modulated (PWM) signal in response to the random pulse sequence to produce at least one modulated PWM output signal. The spectral energy associated with a PWM carrier of the modulated PWM output signal at a carrier frequency and associated harmonics is changed such that the modulated PWM output signal has a spectral shape defined by the particular spectral shape.

Abstract: A signal modulator that can control transmission power if level adjustment of a continuous signal from an oscillator is executed is provided. A pulse generator of one example of a signal modulator includes an oscillator, a control signal generator, a multiplier, a filter, and a control section. The oscillator and the multiplier are active circuits formed of active elements. A continuous signal is output from the oscillator and is input to the multiplier and the multiplier intermittently operates by a control signal output from the control signal generator, whereby a pulse signal is generated and the power level is easily adjusted by a signal from the control section.

Abstract: In a particular embodiment, a circuit device includes a pulse edge control circuit to receive at least one pulse-width modulated (PWM) signal from a PWM source. The pulse edge control circuit is adapted to selectively invert and swap the at least one PWM signal with a logic-inverted duty-cycle complement of the at least one PWM signal at discrete time intervals to produce at least one modulated PWM signal having a changed power spectrum. The pulse edge control circuit provides the at least one modulated PWM signal to at least one output of the pulse edge control circuit.

Abstract: A peak suppressing apparatus includes an amplitude limiter that limits amplitude of the transmission signal with a predetermined threshold; a peak-suppressing-signal extracting unit that extracts a peak suppressing signal by subtracting the transmission signal before the amplitude limiting from the transmission signal amplitude-limited by the amplitude limiter; a filtering unit that performs filtering so that a frequency characteristic of the peak suppressing signal extracted by the peak-suppressing-signal extracting unit becomes flat; and an adder that adds the peak suppressing signal filtered by the filtering unit to the transmission signal.

Abstract: Low noise phase quadrature signals are generated after receiving a clock signal and adjusting the clock signal in response to a feedback signal to generate a phase adjusted clock signal. The clock signal and the phase adjusted clock signal are exclusive-ored to generate a frequency doubled signal. An in-phase local oscillator signal and a quadrature local oscillator signal are generated from the frequency doubled signal such that the in-phase local oscillator and the quadrature local oscillator signal are out-of-phase with each other. In addition, a phase relationship between the in-phase local oscillator signal and the quadrature local oscillator signal are detected, and the feedback signal is generated based upon the phase relationship between the in-phase local oscillator signal and the quadrature local oscillator signal.

Abstract: A pulse width modulating (PWM) circuit includes an activating module and a pulse generating module connected to the activating module. The activating module includes a current resource and a compensation unit. The current source generates an activating current, and the compensating unit detects the activating current and compensates the activating current if the activating current changes. The activating current is input to the pulse generating module to generate pulse voltages output by the pulse generating module.

Abstract: A semiconductor integrated circuit includes a first input terminal configured to input a baseband signal, a second input terminal configured to input a local oscillation signal, an output terminal configured to output a modulating signal, a first amplifier circuit configured to receive the baseband signal through the first input terminal and to output a first amplified signal of the baseband signal, a 2-multiplying circuit configured to receive the local oscillation signal through the second input terminal and to output a 2-multiplied signal of the local oscillation signal, an adder configured to add the 2-multiplied signal and the first amplified signal and to output an addition signal, a second amplifier circuit configured to receive the addition signal and to output a second amplified signal of the addition signal, and a mixer configured to multiply the second amplified signal and the local oscillation signal and to output the modulating signal to the output terminal.

Abstract: A device and method for eliminating narrow-band interference by windowing in a spread spectrum system are disclosed. The method comprises extracting N sampling points of data to perform frequency spectrum transform each time and obtaining N points of data; updating control information, comparing the energy values of the N points with the threshold within the set time period to determine the number of narrow-band interference as well as the width and location of the interference; determining the corresponding frequency domain adjusting window based on the width and location of the narrow band interference, obtaining the points within the window and the adjusted values of those points; with regard to the transformed N points during interference elimination process, setting the energy values of the points within the window during the current time period and the last period as the corresponding adjusted values, outputting the points after frequency spectrum inverse transform.

Abstract: A wireless communication device corrects data transmission errors caused by the simultaneous transmission of multiple streams of data in a Multiple-Input Multiple-Output (MIMO) network. The wireless communication device corrects data transmission errors by removing the signal contribution associated with one or more received signal components from a corresponding received composite signal, thus allowing the remaining components to be decoded relatively free from the signal contribution of the removed components. In one embodiment, the wireless communication device comprises a plurality of antennas and a baseband processor. The antennas are configured to receive a composite signal having a plurality of received signal components.

Abstract: A driver supplies an output voltage to an inductive load. The driver includes an input to receive a pulse width modulated control signal having a controllable duty cycle within a predetermined range. A first switch circuit receives a first switch signal to supply a first voltage, a second switch circuit receives a second switch signal to supply a second voltage, and the output voltage is the difference between the first voltage and the second voltage. An inverter and delay circuit receives the control signal to supply the first switch signal and the second switch signal being inverted and delayed with respect to each other. The delay of the delay circuit is selected to obtain an output voltage having a single polarity for each one of the controllable duty cycles within the predetermined range.

Abstract: A distortion compensation apparatus includes a distortion compensation unit that performs distortion compensation processing on a transmission signal by a series operation, a coefficient update unit that updates a group of series operation coefficients used for the series operation based on a feedback signal of transmission signal output that is output after power amplification processing is performed on output of the distortion compensation unit and the transmission signal, an initial coefficient memory that stores the groups of series operation coefficients that become initial values for coefficient update processing by the coefficient update unit, and a power fluctuation detection unit that detects a power fluctuation of the transmission signal and, when the power fluctuation is detected, reads the groups of series operation coefficients from the initial coefficient memory and provides the groups of series operation coefficients to the coefficient update unit.

Abstract: A first situation indicating that the system is in a power-on situation or an un-mute situation, or a second situation indicating that the system is in a power-off situation or in a mute situation, is detected. When the first situation is detected, a differential PWM signal including a plurality of pulses each having a gradually increased or reduced width and the subsequent pulse train of 50% duty cycle pulses is generated and, if the output of an audio processor is in a stable situation, sent to the amplifier via a multiplexer. When the second situation is detected, the differential PWM signal including a plurality of pulses each having a gradually reduced width and the subsequent pulse train of no signal is generated and, at the same time, the generated pulses are sent to the amplifier via the multiplexer.

Abstract: An arrangement for pulse-width modulating an analog or digital input signal is provided. The non-linear distortion generated in the pulse-width modulator is precompensated by applying a signal with reversed error to the pulse-width modulator. The signal with reversed error is generated by a further pulse-width modulator that receives the input signal and whose output signal is subtracted from twice the input signal. The arrangement may e.g. be used to drive class D audio amplifiers.

Abstract: A system and method for providing a peak power reduced OFDM communications signal are disclosed. The system and method provide peak reduction processing in the time domain followed by inter-symbol interference (ISI) control processing in the frequency domain to maintain modulation errors introduced by the peak reduction processing to an acceptable level. The processing is preferably done on a parallel signal path and the peak corrections with ISI control are added into the main signal path to provide the peak reduced OFDM signal.

Abstract: In a particular embodiment, a circuit device is disclosed that includes a data generator adapted to output a random pulse sequence having a particular spectral shape. The circuit device further includes a pulse edge control circuit to selectively apply a carrier suppression operation to at least one pulse-width modulated (PWM) signal in response to the random pulse sequence to produce at least one modulated PWM output signal. The spectral energy associated with a PWM carrier of the modulated PWM output signal at a carrier frequency and associated harmonics is changed such that the modulated PWM output signal has a spectral shape defined by the particular spectral shape.

Abstract: A predistortion linearized amplifier system that uses analog polynomial based predistortion is disclosed. An analog polynomial function generator receives polynomial parameter updates from a polynomial parameter generator. The polynomial parameter generator uses a combination of analog and digital signal processing to create the parameter updates. This processing is performed on input signal amplitude, detected using analog circuits, and RF coupled samples of the input signal, and the output signal. By using a combination of analog and digital signal processing means, digital processing can be performed at sub-Nyquist rates, significantly reducing the cost of digital circuits. Also, since the predistortion modulation signal is created with an analog function generator, time correlating delay is minimized reducing circuit costs.

Abstract: Digital pulse width modulation with variable period and error distribution that improves the tradeoff between resolution and clock speed in pulse width modulation circuits so that a higher resolution can be achieved with a lower clock speed. A preferred method includes, for a signal sample S and each value of P in a range Pmin to Pmax of pulse periods P, determining a pulse width V=round(P*S), where round(P*S) is the closest integer value of P*S, and the magnitude of the error |E|=|S?V/P|, for the value of V (Vopt) and P (Popt) associated with the lowest value of the magnitude of the error |E|, providing an output pulse of a pulse width Vopt during the pulse period Popt, and successively repeating a) and b). Other aspects of the invention may include error distribution, error squelching to prevent idle-tone, idle-noise artifacts, 2-samples-per-pulse and non-uniform sampling and pulsing. Other features are disclosed.

Abstract: Systems and methods for performance improvements in digital switching amplifiers using low-pass filtering to reduce noise and distortion. In one embodiment, a digital pulse width modulation (PWM) amplifier includes a signal processing plant configured to receive and process an input audio signal. The amplifier also includes a low-pass filter configured to filter audio signals output by the plant. The filtered output of the plant is added to the input audio signal as feedback. The plant may consist of a modulator and power switch, a noise shaper, or any other type of plant. An analog-to-digital converter (ADC) may be provided to convert the output audio signal to a digital signal. Filtering may be implemented before or after the ADC, and a decimator may be placed after the ADC if it is an oversampling ADC.

Abstract: In a particular embodiment, a circuit device is disclosed that includes a data generator adapted to output a random pulse sequence having a particular spectral shape. The circuit device further includes a pulse edge control circuit to selectively apply a carrier suppression operation to at least one pulse-width modulated (PWM) signal in response to the random pulse sequence to produce at least one modulated PWM output signal. The spectral energy associated with a PWM carrier of the modulated PWM output signal at a carrier frequency and associated harmonics is changed such that the modulated PWM output signal has a spectral shape defined by the particular spectral shape.

Abstract: Distortion-compensation amplification apparatus that can obtain an appropriate error vector magnitude without increasing power consumption and can suppress the distortion of a transmission signal appropriately. A distortion compensation section applies distortion compensation to the transmission signal. An amplification section amplifies the transmission signal to which distortion compensation has been applied by the distortion compensation section. A frequency component calculation section calculates the power of frequency components of the transmission signal amplified by the amplification section. A peak suppression section suppresses the peak value of the transmission signal input to the distortion compensation section in accordance with the power of the frequency components calculated by the frequency component calculation section.

Abstract: A circuit for voltage limitation is provided in a transponder with a resonant circuit, which comprises at least one inductor, a capacitor, a depletion layer component with an input, output, and a control input, a first resonant circuit terminal, which is connected to the input of the depletion layer element, and a second resonant circuit terminal, which is connected to the output of the depletion layer element, whereby there is a connection between the control input of the depletion layer component and the first resonant circuit terminal and the second resonant circuit terminal. A method for voltage limitation in a transponder is provided, whereby for voltage limitation in the transmitting and receiving resonant circuit, the control terminal of the depletion layer element is driven by the voltage of the first and second resonant circuit terminal.

Abstract: A radio frequency modulator system having a radio frequency amplifier controlled by a pulse modulator. The pulse modulator includes: a first switching circuit response to an input pulse for coupling a dc voltage relative to a reference potential to the output electrode when the radio frequency signal is to be amplified by the radio frequency amplifier and for decoupling the dc voltage from the output electrode when the radio frequency signal is to be decoupled from the output electrode wherein charge is stored in the storage element when the dc voltage is coupled to the output electrode; and: a second switching circuit responsive to the input pulse for discharging the stored charge when the dc voltage is decoupled from the output electrode.

Abstract: In a particular embodiment, a circuit device includes a pulse edge control circuit to receive at least one pulse-width modulated (PWM) signal from a PWM source. The pulse edge control circuit is adapted to selectively invert and swap the at least one PWM signal with a logic-inverted duty-cycle complement of the at least one PWM signal at discrete time intervals to produce at least one modulated PWM signal having a changed power spectrum. The pulse edge control circuit provides the at least one modulated PWM signal to at least one output of the pulse edge control circuit.

Abstract: A quadrature modulator divides a first signal input as a local signal into an I channel signal and a Q channel signal orthogonal to each other and outputs a second signal having a desired phase delay corresponding to direct current voltages as for the first signal by giving the direct current voltages Vi and Vq to the I channel signal and the Q channel signal, respectively. A phase comparison unit detects a phase difference ? between the first signal and the second signal. A setting unit sets the desired phase delay. A controller section controls the direct current voltages supplied to the I channel signal and the Q channel signal respectively in the quadrature modulator so that an output value corresponding to the phase difference ? detected by the phase comparison unit is equal to a value corresponding to the desired phase delay set by the setting unit, and controls the direct current voltages to be the direct current voltages Vi and Vq satisfying the relation of Vi=cos ? and Vq=sin ?.

Abstract: A system is described for generating a discrete noise-shaped variable switching frequency signal that may be used to define a digital pulse width modulation (“PWM”) period. The system may define a switching frequency waveform that may be used to generate a current switching frequency signal as a function of a system clock. The system may quantize the current switching frequency signal to generate a discrete switching frequency signal that is realizable with the system clock. The system may detect quantization noise and input the noise into the current switching frequency signal to eliminate or reduce discrete tones at the switching frequencies of a PWM signal spectrum.

Abstract: A pulse amplitude modulation (PAM) signal generator that injects a copy of a pulse into the PAM baseband signal prior to frequency upconversion and power amplification. The pulse comprises a function of, or an extra copy of, a pulse in the PAM baseband signal. The pulse injector analyzes the PAM baseband signal for times when a predetermined threshold is exceeded and forms a pulse that is constructed and arranged to reduce the amplitude of the PAM baseband signal to a desired peak amplitude when the pulse is added to the PAM baseband signal.

Abstract: A fixed wireless access communications system comprises an access point and a plurality of subscriber units. Each subscriber unit (502) contends for access to a communications channel to the access point by transmitting a contention word to the access point during a contention time slot. The contention word is predistorted to compensate for the channel impulse response of the transmission channel so that the access point can decode the contention words without using equalisation. A control unit (512), which may comprise a microprocessor, loads the predistorted contention word (a) into a memory (520) and causes the stored predistorted contention word (a) to be applied to a transmitter (508) during a contention time slot when the subscriber unit (502) wishes to request a transmission channel to transmit data to the access point.

Abstract: A method of limiting at least one peak of a composite signal having multiple carriers signals involves placing energy in at least one bandwidth gap located between respective frequency bandwidths of carrier signals.

Abstract: An IQ modulator's performance is optimized through determination of suitable control parameters by the application of known DC biases as the I and Q inputs. Also known are the relative amplitude and actual phase of the sine and cosine carriers to be modulated before they are summed. It is shown that by measuring an RMS voltage Atotal an appropriate number of times for a related combination of the applied DC biases in conjunction with the other known input parameters, a number of behavior parameters that are indicative of mixer performance can be discovered through analysis, such as the solution of a system of linear equations. The combination of behavior parameters may be assigned a Figure Of Merit (FOM) that can be taken as an indication of the degree to which mixer operation approaches ideal behavior. The control parameters may be perturbed over a selected range, and the extraction of the behavior parameters repeated.

Abstract: A device for predistorting a digital symbol for modulating an RF signal includes a multi-bit buffer connected to an input serial bit stream and providing a parallel bit stream from the input serial bit stream; and a processing module connected to the input parallel bit stream. The processing module converts data bits of the input parallel bit stream into an input digital symbol and inputs a set of gain adjustments and phase adjustments that compensate for a channel distortion. The processing module decides which of the set of gain and phase adjustments to apply depending on a magnitude of the input digital symbol, applies a gain adjustment and a phase adjustment, from the set of gain and phase adjustments, to the input digital symbol to produce a predistorted symbol, and outputs quadrature components of the predistorted symbol to a quadrature modulator.

Abstract: A nonlinear distortion compensating circuit for compensating for a nonlinear distortion caused by a power amplifier for amplifying an input signal has a power calculator for calculating a power value of the input signal, an operating point setting unit for calculating an apparent power value from temperature information, supplied from an external source, representative of the measured temperature of the power amplifier and the power value calculated by the power calculator, based on a relationship, given beforehand to the operating point setting unit, between input vs. output characteristics of the power amplifier and the temperature of the power amplifier, an inverse characteristics calculator for calculating an inversion of the nonlinear distortion from inverse characteristics data, given beforehand to the inverse characteristics calculator, and a complex multiplier for adding the inversion calculated by the inverse characteristics calculator to the input signal.

Abstract: A linear system and an EER system are used in combination such that the EER system can also be used in a cellular phone with a wide output dynamic range. In the EER system, linear control of an amplifier becomes difficult in a low output range. Thus, use of the EER system is limited to a high output range, and the linear system is used in the low output range as in the past. A power efficiency is improved while requirements of linearity are satisfied by this structure. An effective circuit structure is proposed for a switching control system for two systems. In addition, an up-converter is constituted in combination with a step-down element with high responsiveness, whereby a power supply voltage control circuit for the EER system with a wide control range and high responsiveness is provided.