Abstract: A broad power band transmitter utilizing a duty cycle modulator achieves 80dB of power range for 3G signals. The present invention greatly improves the efficiency of transmitters used in mobile phones, for example, by using the duty cycle modulator during medium and low power levels of the transmitting power amplifier. The power amplifier operates in three different modes based upon the amplifier power level selected. The power amplifier operates in an EER mode during high power levels, in a DCM ERR mode during medium power levels, and in a DCM mode during low power levels.

Abstract: A transmitter circuit of the present invention includes: a signal generator 101 that generates an amplitude signal and a phase signal based on an input signal; a signal processor 103 that divides the phase signal into a real component and an imaginary component, and performs a signal process on each of the real component and the imaginary component; BEFs 104, 105 that attenuate unnecessary frequency bands of a real component signal and an imaginary component signal, respectively, which are obtained as a result of the signal process performed by the signal processor; a coordinate system converter 106 that converts an orthogonal coordinate system, which is represented by the real component signal and the imaginary component signal of which the unnecessary frequency bands have been attenuated by the BEFs, to a polar coordinate system, which is represented by an amplitude component signal and a phase component signal; an adder 102 that adds the amplitude component signal provided by the coordinate system converte

Abstract: Disclosed are an angle modulator, a transmission apparatus, and a radio communication apparatus that can compensate phase discontinuity when an operational mode of a voltage controlled oscillator is switched. Angle modulator (100) includes phase difference detection section (150) that detects a difference of phases between an input signal of subtractor (141) and an angle modulated signal, using the result of subtraction by subtractor (141) of frequency locked loop circuit (140); correction control section (160) that generates a control signal for compensating that difference of phases based on that difference of phases; correction section (120) that corrects the phase of the angle modulated signal by adding the control signal to an input signal of angle modulator (100), an input signal of loop filter (142), or an input signal of VCO (143) during a predetermined period after VCO (143) switches the operational mode (from time t3 to time t4).

Abstract: Disclosed is a transmission apparatus, a radio communication apparatus, and a transmission method for making it possible to obtain stable characteristics by controlling the difference of time between an amplitude signal and a phase signal to an optimal point, without depending on a modulated signal nor making the circuit size larger. A multiplier (170) generates, in a pseudo manner, a digital modulated signal corresponding to a signal that is obtained by performing analog to digital conversion on a modulated signal that is generated by an amplitude modulator (140), by multiplying a digital amplitude signal that is obtained by performing analog to digital conversion on an amplitude signal by a digital angle modulated signal corresponding to a signal that is obtained by performing analog to digital conversion on an angle modulated signal.

Abstract: A transmission circuit that performs modulation based on a phase difference signal and an amplitude signal includes an asymmetrical phase rotation device. The asymmetrical phase rotation device performs an operation of subtracting 2? from a value of the phase difference signal when the value of the phase difference signal is greater than a predetermined positive threshold value, or an operation of adding 2? to the value of the phase difference signal when the value of the phase difference signal is less than a predetermined negative threshold value. Accordingly, the transmission circuit has distortion reduction characteristics improved uniformly over a range of frequencies higher or lower than a carrier wave band.

Abstract: A nonlinear filter includes: a determination unit that determines, based on I and Q signals inputted into the determination unit, whether or not to perform pulse insertion; a rotation detector that detects a rotation direction of the I and Q signals on an IQ plane with respect to the origin of the IQ plane; a pulse generator that generates, when the determination unit determines to perform the pulse insertion, a pulse of which at least one of the direction and the magnitude is determined in accordance with at least the detected rotation direction; and an adder that inserts the pulse into the I and Q signals and outputs resultant I and Q signals.

Abstract: Provided is a transmission circuit capable of operating with high linearity and with low noise. An AM variable fc filter uses an AM cutoff frequency to remove a high frequency component from an amplitude signal. An amplifier supplies a power amplifier with a voltage which is a result of amplifying the amplitude signal outputted from the AM variable fc filter. A PM variable fc filter uses a PM cutoff frequency to remove a high frequency component from a phase signal. A phase modulator phase-modulates the phase signal outputted from the PM variable fc filter to output a high-frequency phase-modulated signal. The power amplifier amplifies the high-frequency phase-modulated signal by using the voltage supplied from the amplifier, and outputs a resultant signal as a transmission signal.

Abstract: A low cost high-efficiency all-digital transmitter using all-digital power amplifiers (“DPA”) and various mapping techniques to generate an output signal, which substantially reproduces a baseband signal at a carrier frequency. A baseband signal generator generates a baseband signal which is quantized by a signal processor using a quantization map. A DPA control mapper outputs control signals to phase selectors using the quantized signal and a quantization table. Each phase selector receives one of the control signals and outputs a waveform at a carrier frequency with a phase corresponding to the control signals, or an inactive signal. Each DPA in a DPA array has an assigned weight, receives one of the waveforms from the phase selectors, and outputs a power signal according to the weight of the DPA and the phase of the received waveform. The combined power signal substantially reproduces the baseband signal at the carrier frequency.

Abstract: A bandpass type delta sigma modulation section performs delta sigma modulation on an inputted modulation signal such that quantization noise is reduced in a frequency band which requires low noise. A low pass filter removes a noise component in a high frequency region from the signal on which the delta sigma modulation has been performed. A frequency modulation circuit reduces noise in the frequency band which requires low noise with the bandpass type delta sigma modulation section and the low pass filter, and reduces noise in the vicinity of a direct current component DC with a feedback comparison section and a loop filter.

Abstract: A frequency modulator capable of performing frequency modulation without increasing quantization noise; and a method for adjusting the gain thereof are provided. An input signal is gain-adjusted by a gain adjustment section and outputted to a frequency modulation section. The frequency modulation section is gain-controlled based on a first signal. For setting a digital gain coefficient and an analog gain coefficient of the gain adjustment section, a test signal is inputted. In this state, in a generation section, first control information for setting the digital gain coefficient and second control information for setting the analog gain coefficient are generated based on information regarding a state of the frequency modulation section.

Abstract: A communications transmitter configured to reduce the average-to-minimum magnitude ratio (AMR) of a communications signal includes a symbol mapper, a pulse-shaping filter, an AMR reduction circuit, and a modulator. The symbol mapper operates to generate a sequence of symbols from a binary-source data stream containing a message to be transmitted, and the pulse-shaping filter generates a baseband signal based on the sequence of symbols. The AMR reduction circuit is configured to compare a magnitude of a local minimum of samples of the baseband signal to various magnitude threshold levels, and to modify the baseband signal in one of two manners depending on the relationship of the magnitude of the local minimum and the various threshold levels. Finally, the modulator operates to modulate a carrier signal based on the modulation information contained in the modified baseband signal.

Abstract: A bandpass type delta sigma modulation section 15 performs delta sigma modulation on an inputted modulation signal such that quantization noise is reduced in a frequency band which requires low noise. An LPF 16 removes a noise component in a high frequency region from the signal on which the delta sigma modulation has been performed. A frequency modulation circuit 1 reduces noise in the frequency band which requires low noise with the bandpass type delta sigma modulation section 15 and the LPF 16, and reduces noise in the vicinity of a direct current component DC with a feedback comparison section 11 and a loop filter 12.

Abstract: A data converter that converts an input signal to a signal to be inputted to an amplifier. Specifically, the data converter includes: an amplitude detection section that detects an amplitude level of the input signal; a region determination section that determines whether or not an input power to the amplifier is in a non-linear region of the amplifier based on the amplitude level of the input signal detected by the amplitude detection section; and a signal processing section that converts the input signal to a signal having a lower resolution than that of the input signal if the region determination section determines that the input power to the amplifier is in the non-linear region of the amplifier.

Abstract: A transmitter circuit of the present invention includes: a signal generator 101 that generates an amplitude signal and a phase signal based on an input signal; a signal processor 103 that divides the phase signal into a real component and an imaginary component, and performs a signal process on each of the real component and the imaginary component; BEFs 104, 105 that attenuate unnecessary frequency bands of a real component signal and an imaginary component signal, respectively, which are obtained as a result of the signal process performed by the signal processor; a coordinate system converter 106 that converts an orthogonal coordinate system, which is represented by the real component signal and the imaginary component signal of which the unnecessary frequency bands have been attenuated by the BEFs, to a polar coordinate system, which is represented by an amplitude component signal and a phase component signal; an adder 102 that adds the amplitude component signal provided by the coordinate system converte

Abstract: A transmission circuit capable of transmitting a modulated wave signal using polar modulation in a broad band and with low power consumption is provided. The transmission circuit generates an amplitude signal and a phase signal based on data to be transmitted, and separates the amplitude signal into a low-frequency amplitude signal and a high-frequency amplitude signal. The transmission circuit amplitude-modulates the phase signal in a broad band using the high-frequency amplitude signal in a high-frequency voltage control section 104 and an amplitude modulation section 105 and amplitude-modulates the phase signal into low power consumption using the low-frequency amplitude signal in a low-frequency voltage control section 106 and amplitude modulation section 107.

Abstract: A transmission circuit precisely compensates for an offset characteristic of an amplitude modulation section and operates with low distortion and high efficiency over a wide output power range. A signal generation section outputs an amplitude signal and an angle-modulated signal. An amplitude amplifying section supplies, to the amplitude modulation section, a voltage corresponding to a magnitude of an inputted amplitude signal. The amplitude modulation section amplitude-modulates the angle-modulated signal by the voltage supplied from the amplitude amplifying section, thereby outputting a resultant signal as a modulation signal. A temperature measuring section measures a temperature of the amplitude modulation section.

Abstract: The disclosure relates to a method and apparatus for providing efficient signal transmission. Conventional linear amplifiers are most efficient when operated in compressed mode. In the compressed mode, the digital power amplifier switches between the on and off modes. A digital power amplifier operates in compressed mode only if the incoming signal is an on-off constant envelop signal. In one embodiment, the disclosure provides a method and apparatus for converting a digital baseband signal to on-off constant envelop signals for processing through binary-weighted or thermometer-weighted amplifier which are operated in compressed mode.

Abstract: Provided is a transmission circuit which is small in size, operates with high efficiency, and outputs a transmission signal having high linearity. A signal generation section 11 generates an amplitude signal m(t) and a phase signal. An angle modulation section 17 angle-modulates the phase signal to output an angle-modulated signal. An amplitude calculation section 12 outputs a discrete value signal V(t) having a plurality of discrete values corresponding to a magnitude of the amplitude signal m(t). A dividing section 13 divides the amplitude signal m(t) by the discrete value signal V(t) to output an amplitude signal M(t). A delta-sigma modulation section 14 delta-sigma modulates the amplitude signal M(t) to output a delta-sigma modulated signal. A variable gain amplifier section 15 amplifies the delta-sigma modulated signal by a gain corresponding to the discrete value signal V(t).

Abstract: A broad power band transmitter utilizing a duty cycle modulator achieves 80dB of power range for 3G signals. The present invention greatly improves the efficiency of transmitters used in mobile phones, for example, by using the duty cycle modulator during medium and low power levels of the transmitting power amplifier. The power amplifier operates in three different modes based upon the amplifier power level selected. The power amplifier operates in an EER mode during high power levels, in a DCM ERR mode during medium power levels, and in a DCM mode during low power levels.

Abstract: A frequency modulator capable of performing frequency modulation without increasing quantization noise; and a method for adjusting the gain thereof are provided. An input signal is gain-adjusted by a gain adjustment section and outputted to a frequency modulation section. The frequency modulation section is gain-controlled based on a first signal. For setting a digital gain coefficient and an analog gain coefficient of the gain adjustment section, a test signal is inputted. In this state, in a generation section, first control information for setting the digital gain coefficient and second control information for setting the analog gain coefficient are generated based on information regarding a state of the frequency modulation section.