Abstract: An FM modulator measuring an f-V characteristic of a voltage controlled oscillator in a reduced time period. In the FM modular a characteristic measurement time control section 110 notifies a correction section 108 of a time at which a measurement of the f-V characteristic of a voltage controlled oscillator 103 is to start and a time at which the measurement of the f-V characteristic of the voltage controlled oscillator 103 is to and while a carrier wave frequency is being changed to a predetermined frequency. Thus, the correction section 108 measures the f-V characteristic of the voltage controlled oscillator 103 in a reduced time period.

Abstract: A three-dimensional-optical waveguide is formed by laminating planar substrates such as a plurality of lens substrates and, an isolator substrate and a wavelength division multiplexing filter, the optical substrates at least include a waveguide substrate having a waveguide and a reflecting surface. In the three-dimensional optical waveguide, the planar substrates are positioned by markers integrally formed on at least two of the planar substrates. Light directed into the waveguide is reflected by a reflecting surface and passes through the lens substrates and the isolator substrate.

Abstract: A nonlinearity-compensated section has a pre-set compensation table containing a measured value of a voltage vtc, outputted from a loop filter, which is changed accordingly with respect to a change in a voltage vtfc outputted from a frequency controlling section. The nonlinearity-compensated section sets, in the compensation table, the voltage vtfc of an oscillatory frequency oscillated by a VCO and the voltage vtc associated therewith as reference voltages, and creates a look-up table containing voltage differences obtained by subtracting the above-described reference voltages from the voltages vtfc and vtc, respectively. Thereafter, the nonlinearity-compensated section extracts a compensation value corresponding to the voltage vtc actually outputted from the loop filter by means of the look-up table, and adds the compensation value to an input modulated signal adjusted by a multiplier so as to be outputted.

Abstract: A current control circuit (5) recognizes whether or not a transmission signal is transmitted based on a control signal outputted from a transmission signal control circuit (4). When the transmission signal is transmitted, the current control circuit (5) controls a current flowing into a reception circuit (3) in accordance with control information representing any of at least two modes where the transmission signal is transmitted. When no transmission signal is transmitted, the current control circuit (5) controls the current flowing into the reception circuit (3) in accordance with control information representing a mode where no transmission signal is transmitted.

Abstract: An semiconductor integrated circuit that reduces the influence of noise from a digital circuit block on an analog circuit block, both the circuit blocks being integrated on the same semiconductor substrate. In the wiring that passes through near the analog circuit block and the digital circuit block, having a grounding unit that performs alternate grounding makes it possible to reduce the influence of noise from the digital circuit block on the analog circuit block.

Abstract: A nonlinearity-compensated section 23 has a pre-set compensation table containing a measured value of a voltage vtc, outputted from a loop filter 16, which is changed accordingly with respect to a change in a voltage vtfc outputted from a frequency controlling section 11. The nonlinearity-compensated section 23 sets, in the compensation table, the voltage vtfc of an oscillatory frequency oscillated by a VCO 21 and the voltage vtc associated therewith as reference voltages, and creates a look-up table containing voltage differences obtained by subtracting the above-described reference voltages from the voltages vtfc and vtc, respectively. Thereafter, the nonlinearity-compensated section 23 extracts a compensation value corresponding to the voltage vtc actually outputted from the loop filter 16 by means of the look-up table, and adds the compensation value to an input modulated signal adjusted by a multiplier 22 so as to be outputted.

Abstract: An object of the invention is to provide a receiving circuit where the quality of reception can be prevented from deteriorating when the gain changes, so that the good quality of the received signal can be preserved, as well as a receiving apparatus and a transmitting/receiving apparatus using the receiving circuit. In the configuration of the invention, a switch (113) is converted to a short state in response to a change in the gain of a variable gain amplifier (107) by means of a gain control apparatus 112, and thereby, the output terminal of a high pass filter (111) is fixed at a reference voltage and the cutoff frequency of a low pass filter (108) is increased. As a result, the period during which the DC voltage has transient response properties in the low pass filter (108) can be shortened, and this transient response prevented from passing through the high pass filter (111).

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.

Abstract: A transmission circuit operating at a high efficiency and a low distortion is provided. A signal generation section 11 generates a vector signal and an amplitude signal. A vector modulation section 13 performs vector modulation on the vector signal. An amplification section 15 amplifies the signal processed with the vector modulation. A signal processing section 12 performs predetermined signal processing on the amplitude signal and outputs the resultant signal. A regulator 14 controls a voltage to be supplied to the amplification section 15 based on the magnitude of the signal which is output from the signal processing section 12. The signal processing section 12 determines whether or not the amplitude signal exceeds a threshold value at an interval of a predetermined time period, selects a discrete value to be output based on the determination result, and outputs a signal having the selected discrete value.

Abstract: Provided is a polar modulation apparatus capable of performing power limit with a simple configuration even when controlling a transmission power and increasing the transmission signal output power control range. A polar modulation device (1) includes an amplitude limit unit (6) for limiting an amplitude component of an amplitude signal, a D/A converter (7) for converting an inputted digital signal into an analog signal, a power control unit (8) for performing power control so that the inputted signal is an output signal based on the power control signal, a voltage control circuit (9) for supplying voltage to an amplitude modulator (11) according to the output signal from the power control unit (8), an angle modulator (10) for performing angle modulation according to a phase signal, and an amplitude modulator (11) for performing amplitude modulation on the signal subjected to angle modulation, according to the voltage supplied from the voltage control circuit (9).

Abstract: A switching control circuit includes a serial-to-parallel converter, a rewritable storage device, and a decoder. The serial-to-parallel converter performs serial-to-parallel conversion for converting an inputted first control signal into a first parallel signal, and outputs the first parallel signal. The rewritable storage device has a write mode and a read mode selectively switched over in response to a storage mode switching signal, stores therein data of the first parallel signal in the write mode, and outputs the stored data as a second parallel signal in the read mode. In the read mode, the decoder decodes the first control signal and the second parallel signal to generate and output a plurality of element control signals to a plurality of elements, respectively. In the write mode, the decoder holds the plurality of element control signals generated in the read mode.

Abstract: The direct conversion receiving apparatus has a gain control amplifier for variably amplifying a base band signal based on a gain switching control signal. A high pass filter has a first circuit including capacitors connected in parallel that are inserted in a path connecting an input terminal to an output terminal and switching effective total capacitance of the capacitors based on a first time constant switching control signal, and a second circuit including a resistor for providing a predetermined direct current voltage to the output terminal and switching the effective resistance value of the resistor based on a second time constant switching control signal. A control circuit outputs the gain switching control signal, and the first and second time constant switching control signals according to the change of the gain control of said gain control amplifier.

Abstract: A receiving device includes a receiver circuit for outputting a received signal as a reception electric field intensity signal, an operation control circuit for controlling an operation of the receiver circuit, and an intermittent reception control circuit for outputting a periodic signal. A comparator circuit holds a first threshold indicating that the receiving device has entered a communication area and a second threshold indicating a start of a continuous electric field intensity measurement. If the reception electric field intensity signal is lower than the second threshold, the operation control circuit makes the receiver circuit perform intermittent operation. If the reception electric field intensity signal is equal to or higher than the second threshold, the operation control circuit makes the receiver circuit perform a continuous operation.

Abstract: Provided is a frequency modulation circuit 1 for outputting a highly precise frequency-modulated signal regardless of variation in a characteristic of a VCO 15. A correction value calculation section 17 calculates a correction value Vt2 based on a voltage value (Vtx?Vt1) resulting from subtracting a control voltage Vt1, which is generated by a control voltage generation section 11, from a control voltage Vtx at which a sensitivity of the VCO 15 is maximized. A variable amplifier 18 amplifies the correction value Vt2. An addition section 13 outputs a control voltage Vt3, which results from adding the amplified correction value Vt2 to the control voltage Vt1, to the VCO 15 via a DAC 14.

Abstract: Provided is a transmission circuit which is capable of compensating for an offset voltage and a sensitivity characteristic of a PA, and operating with low distortion and high efficiency. A regulator 18 supplies, to a PA 201, a voltage which is controlled in accordance with an amplitude signal to which a first offset value has been added. A regulator 19 supplies, to a PA 202, a voltage which is controlled in accordance with an amplitude signal to which a second offset value has been added. The PA 201 amplifies, in accordance with the voltage supplied from the regulator 18, a phase-modulated signal outputted from a phase modulator 13. The PA 202 amplifies, in accordance with the voltage supplied from the regulator 19, an output signal of the PA 201. A digital block 11 controls the first and second offset values in accordance with temperature information T measured by a temperature measuring section 21.

Abstract: Provided is a transmission circuit 1 which is capable of precisely compensating for an offset characteristic of an amplitude modulation section 15, and operating with low distortion and high efficiency over a wide output electric power range. A signal generation section 11 outputs an amplitude signal and an angle modulation signal. An amplitude amplifying section 14 inputs, to the amplitude modulation section 15, a signal corresponding to a magnitude of the amplitude signal having been inputted. The amplitude modulation section 15 amplitude-modulates the angle modulation signal with the signal inputted from the amplitude amplifying section 14, and outputs a resultant signal as a modulation signal. The power measuring section 18 measures an output power of the amplitude modulation section 15.

Abstract: Provided is a transmission circuit 1 which precisely compensates for an offset characteristic of an amplitude modulation section 15 and which operates with low distortion and high efficiency over a wide output power range. A signal generation section 11 outputs an amplitude signal and an angle-modulated signal. An amplitude amplifying section 14 supplies, to the amplitude modulation section 15, a voltage corresponding to a magnitude of an inputted amplitude signal. The amplitude modulation section 15 amplitude-modulates the angle-modulated signal by the voltage supplied from the amplitude amplifying section 14, thereby outputting a resultant signal as a modulation signal. A temperature measuring section measures a temperature of the amplitude modulation section 15.

Abstract: A transmission modulation apparatus capable of dealing with characteristic variations of a high-frequency power amplifier without always forming an amplitude loop. Transmission modulation apparatus 100 is configured with level detector 140 that receives input of a level detection control signal and detects the output signal of high-frequency power amplifier 130, and offset voltage correcting section 150 that corrects an offset voltage using collinear approximation including a first point where the relationship between the power supply voltage value and the output voltage starts to shift from linear to non-linear based on an output signal of level detector 140 and a second point where output voltage is a minimum. Offset voltage correction is adaptively executed, and linearity between the voltage value of the baseband amplitude signal and the output voltage of high-frequency power amplifier 130 when the voltage value of the baseband amplitude signal is low is compensated.

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: A differential type voltage control oscillator is formed of a differential tank circuit, an oscillation transistor, and a differential variable capacitance circuit. The differential variable capacitance circuit has a configuration wherein at least one pair of varactor diodes are connected in an anti-parallel manner, and are separated by means of a plurality of capacitors in a direct current manner. In addition, a differential control voltage is generated by a charge pump circuit which is controlled by the output of a phase comparator, and the differential control voltage is directly applied across the anodes and the cathodes of the varactor diodes.