Abstract: Provided is a frequency modulation circuit for outputting a frequency-modulated signal with a high precision. A VCO 13 includes a first variable capacitor 132 having a predetermined capacitance change rate, and a second variable capacitor 133 having a greater capacitance change rate than that of the first variable capacitor 132. When the frequency modulation circuit is applied in a narrowband modulation method, a switch 15 switches a connection path of an open loop such that an input terminal and the first variable capacitor 132 are connected. On the other hand, when the frequency modulation circuit is applied in a wideband modulation method, the switch 15 switches the connection path of the open loop such that the input terminal and the second variable capacitor 133 are connected.

Abstract: The present invention aims to provide a transmitter circuit that is capable of suppressing quantization noise and operating with a high efficiency, a data converter section 13 and a data conversion method for use therein, and a communications device using the same. The data converter section 13 of the present invention performs a predetermined data conversion operation on an input signal. The data converter section 13 includes: a signal processing section 133 for discretizing the input signal to produce a signal having a lower resolution magnitude-wise than that of the input signal; a subtractor section 134 for subtracting the input signal from the signal having a lower resolution to extract quantization noise; a filter 135 for extracting quantization noise near an intended wave frequency; and a subtractor section 136 for removing the quantization noise near the intended wave frequency from the signal having a lower resolution.

Abstract: Provided is a transmitter circuit capable of operating with low distortion and high efficiency even in a modulation method using wide modulation bandwidth. In the transmitter circuit, a signal generation section (11) generates an amplitude signal and an angle-modulated signal. Based on a predetermined characteristic, a compensating filter (12) wave-shaping-processes the amplitude signal. A regulator (14) outputs a signal in accordance with a magnitude of the signal which has been wave-shaping-processed by the compensating filter (12). An amplitude modulator section (15) amplitude-modulates the angle-modulated signal by using the signal outputted from the regulator (14). A characteristic of the compensating filter (12) is an inverse of a transfer characteristic between an input at the regulator (14) and an output at the amplitude modulator section (15).

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 self-calibrating modulator apparatus includes a modulator having a controlled oscillator and an oscillator gain calibration circuit. The oscillator gain calibration circuit includes an oscillator gain coefficient calculator configured to calculate a plurality of frequency dependent oscillator gain coefficients from results of measurements taken at the output of the controlled oscillator in response to a test pattern signal representing a plurality of different reference frequencies. The plurality of frequency dependent gain coefficients determined from the calibration process are stored in a look up table (LUT), where they are made available after the calibration process ends to scale a modulation signal applied to the modulator. By scaling the modulation signal prior to it being applied to the control input of the controlled oscillator, the nonlinear response of the controlled oscillator is countered and the modulation accuracy of the modulator is thereby improved.

Abstract: A dual-polarization receiver for receiving polarized wave signals whose directions are different from each other has receiving demodulation units of a working system and a backup system for one of the polarized wave signals, and receiving demodulation units of a working system and a backup system for the other of the polarized wave signals. RF local oscillation circuits of frequency converting circuits of the working system are connected with a common REF oscillation circuit and RF local oscillation circuits of frequency converting circuits of the backup system are connected with a common REF oscillation circuit.

Abstract: A compact transmission circuit for outputting a highly linear transmission signal regardless of the output power level and operating at a high efficiency is provided. A signal generation section 11 generates an amplitude signal and quadrature data based on input data. A calculation section 21 calculates using the amplitude signal and the quadrature data to output a discrete value having a level discrete at every predetermine time period, and first and second phase signals. An amplitude amplification section 17 outputs a voltage controlled in accordance with the discrete value. Angular modulation sections 13 and 14 angular-modulate the phase signals and output first and second angle-modulated signals. Amplitude modulation sections 15 and 16 amplitude-modulate the angle-modulated signals with the voltage from the amplitude amplification section 17 and output first and second modulated signals. A combining section 18 combines the first and second modulated signals and outputs a transmission signal.

Abstract: The amplitude modulator comprises: an angle modulator for angle-modulating a phase signal to be inputted; a waveform shaping means in which, (1) when the magnitude of an amplitude signal to be inputted becomes smaller than a first prescribed value, a waveform of the amplitude signal is shaped so that the magnitude of the amplitude signal of the portion which becomes small becomes the first prescribed value; and/or (2) the waveform shaping means in which, when the magnitude of the amplitude signal to be inputted becomes larger than the second prescribed value which is larger than the first prescribed value, the waveform of the amplitude signal is shaped so that the magnitude of the amplitude signal of the portion which becomes larger becomes the second prescribed value; and an amplitude modulator for amplitude modulating the signal of the output of the angle modulator by the signal of the output of the waveform shaping means.

Abstract: A transmission circuit for outputting transmission signals with a low distortion and a high efficiency over a wide range of output power is provided. A signal generation section (11) generates an amplitude signal and a phase signal. An angle modulation section (12) performs angle modulation on the phase signal and outputs an angle-modulated signal. A regulator (14) receives the amplitude signal via a variable gain amplification section (18) and supplies a voltage controlled based on the magnitude of the amplitude signal to the amplitude modulation section (15). The amplitude modulation section (15) performs amplitude modulation on the angle-modulated signal and outputs a modulated signal to the variable attenuation section (16). When the value of power information is smaller than a predetermined threshold value, the control section (19) increases the gain of the variable gain amplification section (18) and the attenuation of the variable attenuation section (16).

Abstract: In a first mode in which the power level of a transmission output signal (S6) is to be high, an output from the multiplier (2) is input to an amplitude modulation signal amplifier (4), and a radio frequency power amplifier (5) performs amplitude modulation on a radio frequency phase modulated signal (S4) using a nonlinear area with a supply voltage from the amplitude modulation signal amplifier (4). In a second mode in which the power level of a transmission output signal (S6) is to be low, the output from the multiplier (2) is input to a variable gain amplifier (7), and the variable gain amplifier (7) performs amplitude modulation on the radio frequency phase modulated signal (S4). The amplitude modulated signal is output without passing through the radio frequency power amplifier (5).

Abstract: Provided are generating an amplitude signal and a frequency signal through signal processing of data, angle-modulating the frequency signal, adjusting a delay time of the amplitude signal, amplitude amplifying of outputting a signal based on a magnitude of the amplitude signal having the delay time adjusted, amplitude-modulating a signal outputted through the angle modulating, by the signal outputted through the amplitude amplifying, so as to output an obtained signal as a modulated signal, and delay processing of calculating a delay time difference between the amplitude signal and the frequency signal, based on the modulated signal, and performing feedback control for the delay time until the delay time difference is eliminated, only in a test period. Through the signal generating, a sinusoidal signal is outputted as each of the amplitude signal and the frequency signal during the test period.

Abstract: A phase modulation section (101) generates a first modulated signal including phase information. An amplitude signal control section (103) generates a second modulated signal including amplitude information. A waveform shaping section (104), when an amplitude of the second modulated signal is larger than a regulated value generates a waveform-shaped modulated signal. An amplitude modulated voltage supply section (105) amplifies the waveform-shaped modulated signal based on the supply voltage from a voltage control section (106) and supplies the amplified signal to a power amplification section (102). The power amplification section (102) amplifies the first modulated signal based on the amplitude modulated voltage, and outputs the resultant signal.

Abstract: A self-calibrating modulator apparatus includes a modulator having a controlled oscillator and an oscillator gain calibration circuit. The oscillator gain calibration circuit includes an oscillator gain coefficient calculator configured to calculate a plurality of frequency dependent oscillator gain coefficients from results of measurements taken at the output of the controlled oscillator in response to a test pattern signal representing a plurality of different reference frequencies. The plurality of frequency dependent gain coefficients determined from the calibration process are stored in a look up table (LUT), where they are made available after the calibration process ends to scale a modulation signal applied to the modulator. By scaling the modulation signal prior to it being applied to the control input of the controlled oscillator, the nonlinear response of the controlled oscillator is countered and the modulation accuracy of the modulator is thereby improved.

Abstract: A transmission circuit is provided which can output a stable transmission signal independently of the temperature characteristics of an amplitude modulating section. A signal generating section generates an amplitude signal and a phase signal. A regulator supplies a voltage which is controlled, depending on the amplitude signal, to the amplitude modulating section. An angle modulating section subjects the phase signal to angle modulation to output an angle-modulated signal. A temperature detecting section outputs temperature information of the amplitude modulating section. A gain control section controls a gain of a variable gain amplifier based on the temperature information of the amplitude modulating section. The variable gain amplifier amplifies the angle-modulated signal using the gain controlled by the gain control section.

Abstract: Provided is a transmitter circuit capable of outputting a transmission signal having high accuracy irrespective of bandwidth and operating with high efficiency. In the transmitter circuit 1, a delay detection section 18 selects two observation points at which angle change amounts of the complex envelope are larger than a predetermined angle threshold value and selects, as a singular point, an observation point at which a magnitude of the complex envelope is larger than that at one of the two observation points. Based on a positional relationship among the singular point, a preceding symbol, and a succeeding symbol, a relationship between delay times of the amplitude signal and the phase signal is detected. Based on the relationship between delay times of the amplitude signal and the phase signal, a delay setting section 19 sets a delay time in a delay adjuster 12. Based on the set delay time, the delay adjuster 12 adjusts the delay times of the amplitude signal and the phase signal.

Abstract: A signal generation section 11 generates an amplitude signal M and an angle-modulated signal S?. An adaptive compensation filter 12 performs waveform shaping on the amplitude signal M in accordance with a magnitude of the amplitude signal M. An amplitude amplification section 14 outputs a signal proportional to a magnitude of the signal subjected to waveform shaping in the adaptive compensation filter 12. An amplitude modulation section 15 amplitude-modulates the angle-modulated signal by the signal outputted from the amplitude amplification section 14 and outputs the resulting signal as a modulated signal. Characteristics of the adaptive compensation filter 12 are inverse characteristics of transfer characteristics from an input of the amplitude amplification section 14 to an output of the amplitude modulation section 15.

Abstract: A transmission circuit for outputting transmission signals with a low distortion and a high efficiency over a wide range of output power is provided. A signal generation section (11) generates an amplitude signal and a phase signal. An angle modulation section (12) performs angle modulation on the phase signal and outputs an angle-modulated signal. A regulator (14) receives the amplitude signal via a variable gain amplification section (18) and supplies a voltage controlled based on the magnitude of the amplitude signal to the amplitude modulation section (15). The amplitude modulation section (15) performs amplitude modulation on the angle-modulated signal and outputs a modulated signal to the variable attenuation section (16). When the value of power information is smaller than a predetermined threshold value, the control section (19) increases the gain of the variable gain amplification section (18) and the attenuation of the variable attenuation section (16).

Abstract: Provided is a transmitter circuit capable of operating with low distortion and high efficiency even in a modulation method using wide modulation bandwidth. In the transmitter circuit, a signal generation section (11) generates an amplitude signal and an angle-modulated signal. Based on a predetermined characteristic, a compensating filter (12) wave-shaping-processes the amplitude signal. A regulator (14) outputs a signal in accordance with a magnitude of the signal which has been wave-shaping-processed by the compensating filter (12). An amplitude modulator section (15) amplitude-modulates the angle-modulated signal by using the signal outputted from the regulator (14). A characteristic of the compensating filter (12) is an inverse of a transfer characteristic between an input at the regulator (14) and an output at the amplitude modulator section (15).

Abstract: An amplifier includes a modulation coder receiving an original modulation signal and generating an amplitude signal and a phase signal, a voltage adjusting instrument which generates an amplitude modulation signal from the amplitude signal, a carrier generator generating a phase modulation signal from the phase signal, and an amplification device receiving the phase modulation signal and the amplitude modulation signal serving as a bias voltage and outputting a modulation signal obtained by restoring and amplifying the original modulation signal. The voltage adjusting instrument determines a DC offset voltage on the basis of a level control signal indicating the level of the amplitude modulation signal and generates the amplitude modulation signal to which the DC offset voltage is added.

Abstract: A small-size transmission circuit is provided which outputs a transmission signal having high linearity independently of a magnitude of an output power, and operates with high efficiency. A signal generating section generates quadrature data based on input data. A computation section compares an amplitude component of the quadrature data with a predetermined amplitude threshold value, and outputs an amplitude signal, a first phase signal, and a second phase signal. A regulator outputs a voltage controlled depending on the amplitude signal. An angle modulation section and an angle modulation section angle-modulate the phase signal to output first and second angle-modulated signals. An amplitude modulation section and an amplitude modulation section amplitude-modulate the first and second angle-modulated signals using a voltage controlled depending on the amplitude signal to output the angle-modulated and amplitude-modulated signals as a first modulated signal and a second modulated signal.