Abstract: A VCO driving circuit and a frequency synthesizer wherein the impedance viewed from a VCO control terminal is reduced to prevent the VCO phase noise characteristic from degrading. A VCO driving circuit and a frequency synthesizer having the VCO driving circuit, which comprises a coarse adjustment DAC that receives a digital data, which has a coarse adjustment frequency, to output an analog signal; a fine adjustment DAC that receives a digital data, which has a fine adjustment frequency, to output an analog signal; a low response speed LPF5 that removes noise from the output signal from the coarse adjustment DAC and then provides the resultant signal as an input to a VCO control terminal; a high response speed LPF7 that converts the output signal from the fine adjustment DAC to a voltage, thereby smoothing the signal; a resistor that connects an input stage of the LPF5 to that of the LPF7; and a capacitor used for providing a capacitive coupling such that the output of the LPF7 is added to that of the LPF5.

Abstract: There is provided a signal processing device and a wireless apparatus capable of not erroneously determining polarity, appropriately performing a spread modulation process, a carrier modulation process, and reception data demodulation process, improving reception accuracy, and miniaturizing a circuit, even when IF carrier frequency shift occurs.

Abstract: A TMCC carrier is demodulated from a received OFDM signal having a TMCC carrier. A relative carrier position of the demodulated TMCC carrier is detected. A carrier shift amount is detected from the detected relative carrier position of the TMCC carrier and a normal TMCC carrier position. The received OFDM signal is corrected for the carrier frequency shift based on the detected carrier shift amount.

Abstract: An object of the present invention is to provide a sensing instrument capable to detect a substance existing in a very small quantity, such as environmental pollutants, instantly with a high degree of precision. As a specific means for solving the problem, a frequency signal from a crystal oscillator is sampled using a frequency signal from a reference clock generating part, the sampling value is outputted in a digital signal, quadrature detection is conducted with the digital signal for a frequency signal corresponding to the output signal, the rotational vector rotating at a frequency corresponding to the difference between the frequency of the frequency signal and the frequency of a sinusoidal wave used for the quadrature detection is taken out, and the variation of the frequency is detected by detecting the velocity of the rotational vector based on the respective sampling values.

Abstract: Difference between a received signal which is an OFDM modulated signal having a guard interval and a delayed signal acquired by delaying the received signal by time equivalent to a data interval is calculated, a reference signal of an FFT calculation window is generated based upon the acquired result of the calculation of the difference and a predetermined threshold and a boundary between symbols is detected. As a result, the boundary between symbols can be stably detected, compared with a method of detecting a boundary between symbols based upon the result of the correlation calculation of the guard interval and the demodulation of received data is also stably enabled in multipath phasing and ghost.

Abstract: If a total number of specific RF tags is too large, many RF tags respond at a time. Therefore a problem occurs that an interrogator cannot receive information from the RF tags. A first invention relates to an RF tag. The RF tag includes an interrogator signal receiving section for receiving an interrogator signal from an interrogator, a synchronizing signal generating section for generating a synchronizing signal from the received interrogator signal, a response information obtaining section for obtaining response information according to the interrogator signal, a spread-code modulating section for modulating the response information with a spreading code and obtaining the spread-code modulated response information, and a transmitting section for transmitting the response signal that contains the spread-code modulated response information in a data area at a random transmission interval in synchronism with the synchronizing signal.

Abstract: An object of the present invention is to provide a sensing instrument capable to detect a substance existing in a very small quantity, such as environmental pollutants, instantly with a high degree of precision. As a specific means for solving the problem, a frequency signal from a crystal oscillator is sampled using a frequency signal from a reference clock generating part, the sampling value is outputted in a digital signal, quadrature detection is conducted with the digital signal for a frequency signal corresponding to the output signal, the rotational vector rotating at a frequency corresponding to the difference between the frequency of the frequency signal and the frequency of a sinusoidal wave used for the quadrature detection is taken out, and the variation of the frequency is detected by detecting the velocity of the rotational vector based on the respective sampling values.

Abstract: A distortion compensating circuit for a power amplifier attains raised compensating accuracy with shorter convergence time by accurately and quickly generating a distortion compensation signal for pre-distortion. An error signal representing the difference between the input and output signals of the power amplifier is generated. From the error signal and the input signal, the coefficients of the third-order intermodulation distortion, fifth-order intermodulation distortion and seventh-order intermodulation distortion are calculated. According to these coefficients, a distortion compensating signal which is characteristically opposite in phase and gain to the intermodulation distortions is generated.

Abstract: The invention provides an instruction manual capable of storing documents such as guarantee certificates easily thereto. An instruction manual 1 of an electronic device having its rear portion 2 bound in a spreadable manner has a back cover 3 disposed on the outer side of the instruction manual and a paper portion 4 overlapped therewith which are bound together at their upper edges 5, lower edges 6 and side edges 9, thereby forming a document storage portion 7 between the back cover 3 and the paper portion 4. The back cover 3 has a document insertion slot 12. Thus, documents such as a guarantee certificate 11 can easily be stored in the document storage portion 7 through document insertion slots 12 without having to open the instruction manual 1.

Abstract: A distortion compensating circuit for a power amplifier attains raised compensating accuracy with shorter convergence time by accurately and quickly generating a distortion compensation signal for pre-distortion. An error signal representing the difference between the input and output signals of the power amplifier is generated. From the error signal and the input signal, the coefficients of the third-order intermodulation distortion, fifth-order intermodulation distortion and seventh-order intermodulation distortion are calculated. According to these coefficients, a distortion compensating signal which is characteristically opposite in phase and gain to the intermodulation distortions is generated.

Abstract: A current detecting portion A includes a magnetic shield attached to a bus bar BU, a magnetic shield attached to a bus bar BV, and a magnetic shield attached to a bus bar BW. On bus bars BV, BU and BW arranged in parallel, current sensors SU, SV and SW are arranged at alternately displaced positions along each bus bar. The magnetic shields are also arranged at alternately displaced positions along each bus bar. The arrangement of the magnetic shield and the current sensors is what is called a staggered arrangement, whereby magnetic interference from an adjacent bus bar to a current sensor can be avoided.

Abstract: A high-frequency wireless communication device is provided that is capable of enlarging the range of communication by enhancing reception sensitivity while avoiding mutual interference. The device comprises an antenna filter and a direct detection type reception mechanism connected to the antenna filter. A crystal filter is used as the antenna filter. A crystal chip constituting the crystal filter and an IC chip into which the reception mechanism is integrated are housed in a single modular container to configure a high-frequency wireless module.

Abstract: A transmission apparatus of orthogonal frequency division multiplexing for multiplexing a plurality of carriers orthogonal to one another to transmit a modulated signal. The transmission apparatus includes a first modulator for outputting a code modulated in accordance a modulation scheme which can be applied with a synchronous detection for demodulation, a second modulator for outputting a code modulated in accordance with a modulation scheme different from the modulation scheme associated with the first modulator, and a distributing circuit for distributing the codes modulated by the first and second modulators to a plurality of carriers. The distributing circuit distributes the code modulated by the second modulator to all or some of carriers existing within a predetermined number of columns from at least one of both end regions of a signal transmission frequency band, and the code modulated by the first modulator to the remaining carriers.

Abstract: A distortion compensating circuit for a power amplifier attains raised compensating accuracy with shorter convergence time by accurately and quickly generating a distortion compensation signal for predistortion. An error signal representing the difference between the input and output signals of the power amplifier is generated. From the error signal and the input signal, the coefficients of the third-order intermodulation distortion, fifth-order intermodulation distortion and seventh-order intermodulation distortion are calculated. According to these coefficients, a distortion compensating signal which is characteristically opposite in phase and gain to the intermodulation distortions is generated.

Abstract: A TMCC carrier is demodulated from a received OFDM signal having a TMCC carrier. A relative carrier position of the demodulated TMCC carrier is detected. A carrier shift amount is detected from the detected relative carrier position of the TMCC carrier and a normal TMCC carrier position. The received OFDM signal is corrected for the carrier frequency shift based on the detected carrier shift amount.

Abstract: A demodulation circuit for demodulating a multilevel digital modulation signal. Only an in-phase or quadrature component of the training signal generated in the demodulation circuit is used for equalization convergence. Tap coefficients of an equalizing training equalizer are updated by supplying either the in-phase or quadrature component so that the calculation amount can be reduced. When the equalization convergence is established, the obtained tap coefficients are rotated in phase and set to a data reproduction equalizer.

Abstract: A distortion compensating circuit for a power amplifier attains raised compensating accuracy with shorter convergence time by accurately and quickly generating a distortion compensation signal for pre-distortion. An error signal representing the difference between the input and output signals of the power amplifier is generated. From the error signal and the input signal, the coefficients of the third-order intermodulation distortion, fifth-order intermodulation distortion and seventh-order intermodulation distortion are calculated. According to these coefficients, a distortion compensating signal which is characteristically opposite in phase and gain to the intermodulation distortions is generated.

Abstract: A data transmission system for transmitting data from a transmitter to a receiver located away therefrom. The transmitter includes circuitry for transmitting together a main signal having a carrier modulated with main data to be transmitted and as well as a sub-signal to be used in frequency conversion and generated by modulating a carrier of a predetermined frequency out of a frequency band of the main signal. The receiver includes circuitry for receiving a receive signal from the transmitter and extracting the sub-signal therefrom and also includes circuitry for generating a signal to be used as a reference at the time of converting the receive signal to a signal having a predetermined frequency on the basis of the extracted sub-signal.

Abstract: An encoder and a decoder each having an error correcting operation, and a data transmission apparatus using them for data transmission in a multilevel modulation system. In transmission data is converted into parallel data. One bit thereof is inputted to a convolutional encoder to output two bits. Two bit data and another signal of the parallel data not inputted to the convolutional encoder are respectively separated into real part and imaginary part to independently decide signal points for the parallel data. In reception an area is similarly decided independently for real and imaginary parts and metric is assigned for the data. Real and imaginary parts are combined with each other for Viterbi decoding. Result thereof is fed to a convolutional encoder similar in constitution to that on transmission side. Using convolutional encoding output and decided area, transmission data is decoded.

Abstract: A demodulation circuit for demodulating a multilevel digital modulation signal. Only an in-phase or quadrature component of the training signal generated in the demodulation circuit is used for equalization convergence. Tap coefficients of an equalizing training equalizer are updated by supplying either the in-phase or quadrature component so that the calculation amount can be reduced. When the equalization convergence is established, the obtained tap coefficients are rotated in phase and set to a data reproduction equalizer.