Abstract: A voltage controlled oscillator comprises a parallel resonance circuit including an inductor circuit, a variable capacitance circuit, and a high-frequency switch circuit, a negative resistance circuit and a frequency control section, and a frequency tuning sensitivity control section. The frequency control section shifts a band of an oscillation frequency by controlling ON/OFF of a switching element included in the high-frequency switch circuit. The frequency tuning sensitivity control section adjusts a change rate of a total capacitance of the variable capacitance circuit with respect to a control voltage, depending on a band to be used. The frequency tuning sensitivity control section is connected to a virtual ground point of a differential signal.

Abstract: A frequency modulation apparatus 100 has a synthesizer 101, a differentiator 102 that differentiates phase modulation data and generates differential phase modulation data, an adder 103 that adds together that differential phase modulation data and carrier frequency data fractional part K and generates addition fractional part K1, an input data operation section 104 that receives addition fractional part K1 and carrier frequency data integer part M, generates integer part input data M1 and fractional part input data K2, and provides fractional part input data K2 to synthesizer 101, and an integer part data delay section 105 that delays integer part input data M1 before providing it to synthesizer 101. Input data operation section 104 makes M1=M?1 and K2=K1+1 when K1<0, makes M1=M and K2=K1 when 0?K1<1, and makes M1=M+1 and K2=K1?1 when 1?K1.

Abstract: An optical mount substrate and a manufacturing method of the optical mount substrate. An optical fiber guide section for arranging and fixing an optical transfer section, having an optical waveguide or an optical fiber, is formed. An electrical conductivity member is embedded in the optical mount substrate so that it penetrates a first principal plane of an arrangement section for arranging an optical device optically connected with the optical waveguide or the optical fiber on the first principal plane, and a second principal plane of the arrangement section parallel to the first principal plane. The optical fiber guide section and the arrangement section are formed by pressing a mold member to a heated and softened substrate to transfer inversion geometry of the mold member onto the substrate. The electrical conductivity member, having a predetermined shape, is directly pressed onto the heated and softened substrate to embed it into the substrate.

Abstract: A voltage controlled oscillator 1, a variable frequency divider 2, a phase comparator 3, and a loop filter 4 form a Phase Locked Loop (PLL). A sigma-delta modulator 5 sigma-delta modulates data obtained by adding a fractional part M2 of the frequency division factor data with modulation data X by using an output signal of the variable frequency divider 2 as a clock. An output signal of the sigma-delta modulator 5 is added to an integral part M1 of the frequency division factor data, and the resultant data becomes effective frequency division factor data 13 of the variable frequency divider 2. An output signal of the sigma-delta modulator 5 also becomes control data 14 after passing through a D/A converter 6, a low-pass filter 7, and an amplitude adjustment circuit 8. The control data 14 is inputted into a frequency modulation terminal of the voltage controlled oscillator 1.

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: The data from the orthogonal data generator is quantized by the vector data converter so as to become, for example, a binary value of 0 and a real number in magnitude. The output of the vector converter is modulated by the modulator, and is inputted to the amplifier. In the amplifier, the envelope of the signal to be inputted is quantized. That is, the signal of a constant envelope becomes a signal which is turned ON and OFF, so that a highly efficient nonlinear amplifier can be used. The quantization noise generated in the vector data converter is removed by the filter, and after that, the signal of a low distortion and a low noise is outputted from the output terminal. The isolation unit is connected between the amplifier and the filter, avoiding effects on the output impedance of the amplifier from the filter, so that a signal of a low distortion can be outputted.

Abstract: The present invention provides a differential voltage control oscillator including: a parallel resonance circuit in which an inductor circuit, a variable capacitance circuit, and a radio-frequency switching circuit are connected in parallel together; and a negative resistance circuit connected in parallel with the parallel resonance circuit.

Abstract: The conventional feedforward amplifier is unable to suppress distortion components efficiently. The present invention provides a feedforward amplifier wherein the vector adjustor is adjusted so that (1) suppression is performed on only the distortion component generated within a predetermined frequency range out of the range of frequencies to be suppressed in which distortion components to be suppressed occur or (2) the suppression of the distortion component generated within the predetermined frequency range is greater than the suppression of the distortion component generated within the frequency range other than the predetermined frequency range out of the range of frequencies to be suppressed, and the pre-distortion circuit is adjusted so that at least the distortion component generated within the frequency range other than the predetermined frequency range is suppressed.

Abstract: In a differential capacitor1, first and second capacitors 1003 and 1004 are formed in substantially symmetrical positions from each other with respect to a vertical plane B-B?, on a semiconductor substrate 1020. The differential capacitor 1 further includes a shield plate 1022 interposed between the semiconductor substrate 1020 and the lower electrodes 1016 and 1018. When each of the lower electrodes 1016 and 1018 is projected onto the shield plate 1022 along the vertical direction, each projected lower electrode 1016 or 1018 has a partial overlap with the shield plate 1022.

Abstract: A voltage-controlled oscillator having an inductor circuit, n pieces (n is two or more) of variable capacitance circuit having variable capacitance elements, negative resistance circuits, and reference voltage generation means of generating a reference voltage from a power supply voltage, and wherein a predetermined reference voltage is inputted to some terminals of the variable capacitance elements of the n pieces of variable capacitance circuit, a control voltage is inputted to the other terminals thereof, and of the variable capacitance elements of the n pieces of variable capacitance circuits, the predetermined reference voltage inputted to some terminals of the variable capacitance elements of at least two pieces of the variable capacitance circuit is different.

Abstract: The present invention provides an oscillator or PLL circuit which can balance the characteristics of a circuit without being affected by noise from a signal line or a supply line. There is provides an oscillator comprising a resonance circuit has a first series connected circuit having coils and a power terminal, a second series connected circuit having capacitors and a varactor having directional characteristics, and a third series connected circuit having capacitors and a varactor having directional characteristics. The first, second, and third series connected circuits are connected in parallel. The varactors are connected so as to have opposite directionalities with respect to a connection side of the second and third series connected circuit. The capacities of the varactors are varied by external control. The varied capacities determine an oscillation frequency.

Abstract: A transformer element 1 is formed on a semiconductor substrate using first and second wiring layers arranged parallel to each other in a vertical direction, and includes a first inductor 2 and a second inductor 3. The first and second inductors 2 and 3 are each provided using the first and second wiring layers such that if projected into one of the first and second wiring layers either along a vertical upward direction or a vertical downward direction, outlines of a projection form a symmetrical shape with respect to a predetermined reference plane, and portions corresponding to intersections between the outlines of the projection on the wiring layer are formed so as to be out of contact with each other.

Abstract: The present invention is directed to a data converter for converting an input signal to a signal to be inputted to an amplifier. The data converter includes: an amplitude detection section for detecting an amplitude level of the input signal; a region determination section for determining 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 for converting 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 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: The present invention provides a voltage controlled oscillator for changing an oscillating frequency in accordance an input control voltage, including a parallel resonant circuit, a negative resistance circuit connected in parallel to the parallel resonant circuit, a first capacitor connected in parallel to the negative resistance circuit, a first current source connected between one terminal of the first capacitor and the negative resistance circuit, and a second current source connected between the other terminal of the first capacitor and the negative resistance circuit. The capacitance value of the first capacitor is set to a value that suppresses a signal with a frequency twice the oscillating frequency at both the terminals of the first capacitor. Each of the first and the second current sources is constituted by a bipolar transistor.

Abstract: An amplifier circuit has: a delta-sigma modulator which delta-sigma modulates a signal; and an amplifier which is connected to an output of the delta-sigma modulator. In the amplifier circuit, an output voltage of the delta-sigma modulator is controlled in accordance with an output power of the amplifier. When the output power of the amplifier is reduced, the output voltage of the delta-sigma modulator is lowered.

Abstract: The present invention provides an amplifier for amplifying a high-frequency signal and outputting an amplified signal. The amplifier includes: an amplification element which is a bipolar transistor or a field-effect transistor; and an inductor connected between a base and a collector or between a gate and a drain of the amplification element. The inductance of the inductor is chosen so that, within a predetermined frequency range, a parallel resonance occurs with a parasitic capacitor of the amplification element and an intrinsic capacitor of the amplification element, the intrinsic capacitor being a base-collector capacitance or a gate-drain capacitance.

Abstract: A high frequency variable gain amplification device 100 includes: a feedback circuit 103 capable of changing a feedback impedance to adjust the gain of an amplifier 101 in accordance with a control signal from a control device 200; and a current consumption adjustment circuit 102 capable of adjusting current consumption of the amplifier 101. The control device 200 controls the feedback impedance and the current consumption based on a desired signal power level and an undesired signal power level. If the desired signal power level exceeds a predetermined value, the control device 200 reduces the feedback impedance to increase the amount of a feedback signal, thereby allowing the amplifier 101 to operate with low gain so as to prevent the distortion characteristic from being reduced and to reduce the current consumption.

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: In a differential capacitor1, first and second capacitors 1003 and 1004 are formed in substantially symmetrical positions from each other with respect to a vertical plane B-B?, on a semiconductor substrate 1020. The differential capacitor 1 further includes a shield plate 1022 interposed between the semiconductor substrate 1020 and the lower electrodes 1016 and 1018. When each of the lower electrodes 1016 and 1018 is projected onto the shield plate 1022 along the vertical direction, each projected lower electrode 1016 or 1018 has a partial overlap with the shield plate 1022.