Abstract: The present invention provides a 4-mercaptophenyl ester of acetic acid, which is useful as a raw material for synthesizing a developer, etc., and a process for producing the same. The present invention provides a 4-mercaptophenyl ester of acetic acid represented by Formula (1); wherein Ac is an acetyl group, and R is a C1-4 alkyl group, and a process for producing the 4-mercaptophenyl ester of acetic acid having a step of reducing a 4-halosulfonylphenyl ester of acetic acid represented by Formula (2); wherein Ac is an acetyl group, R is a C1-4 alkyl group, and X is a halogen atom.

Abstract: There is provided a signal processing apparatus including a variable capacitor and a switching portion for switching the circuit mode between a sampling mode, in which the variable capacitor samples an input signal, a holding mode, in which a charge gained by sampling the input signal is held in the variable capacitor, and an output mode for outputting the charge stored in the variable capacitor, wherein the variable capacitor is provided with an input terminal through which the input signal is inputted in the sampling mode, a control terminal to which a first control signal which decreases the capacitance of the variable capacitor to a value below the capacitance in the sampling mode is inputted in the output mode, and a second control signal having a predetermined reference voltage is inputted in the holding mode, where an insulating layer is provided between the control terminal and the input terminal.

Abstract: There is provided a signal generating apparatus including: a multiphase oscillating portion for generating a number of base signals having the same frequency and a predetermined phase difference of which the signal level transitions between a first level and a second level, and where periods during which the signal level of any given base signal is at the first level and the signal level of the next base signal having the predetermined phase delay relative to the given base signal is at the first level overlap; and a transition time point changing portion for generating a pulse signal by changing the time point when each base signal transitions from the first level to the second level to a time point before the next base signal transitions from the second level to the first level.

Abstract: A radio transmission apparatus that uses a plurality of band groups and that transmits a signal subjected to frequency hopping between a plurality of bands in each band group at a local frequency apart from the center frequency of each band includes a local frequency generating unit that generates a local frequency lower than the center frequency of each band in a first band group in the transmission with the first band group. The local frequency generating unit generates a local frequency higher than the center frequency of each band in a second band group in the transmission with the second band group, the local frequency to be generated being the same as the local frequency generated in the transmission with the first band group.

Abstract: The present invention suppresses a harmonic component without impairing the phase orthogonality of a pair of complex signals. A polyphase filter is configured so that K pieces of filter circuits, each of which comprises a resistor and a capacitor, are connected and +360/K degrees out of phase with a preceding one. Since counterclockwise rotation occurs when expression is given in terms of the complex plane, a notch occurs in a negative frequency region. A RC value is set so that a notch occurs in a specified frequency band to suppress a (4N+1)-order harmonic component. Since the polyphase filter has a symmetrical structure, an unbalanced component contained in an input signal is eliminated at a frequency that agrees with a pole determined by the RC value. This action improves the orthogonality.

Abstract: The present invention eliminates a DC offset problem due to self-mixing in performing frequency conversion on a multiband OFDM_UWB signal by a direct conversion scheme. Capacitors #1, #2, and #3 are provided for each of the hopping bands #1, #2, and#3. Capacitors are switched in synchronization with frequency hopping. For example, capacitor #1 stores electric charge just before frequency hopping from band #1 to another band #2, and continues a step response after hopping to band #1 again. Soon, the charging/discharging of capacitor #1 ceases and reaches a steady state.

Abstract: A charge domain filter device includes a SINC filter with a frequency characteristic expressed by a SINC function, and a bandpass filter connected to an output end of the SINC filter and having a frequency characteristic with a particular center frequency.

Abstract: There is provided a charge domain filter device including a plurality of transconductors each of which converts an input voltage to a current and outputs the current and a filter unit that filters output signals from said plurality of transconductors by repeatedly charging and discharging a plurality of capacitors, wherein an impulse response of the charge domain filter device is obtained through convolution of a first impulse corresponding to a charge time length over which said capacitors are charged and a second impulse corresponding to each of said plurality of transconductors.

Abstract: An objective is to perform pulse modulation so as to allow for an effect of inter-symbol interference in the UWB communication. For this purpose, a reference clock signal is generated. Spread data is sequentially output at a specified timing synchronized with the reference clock. In this case, the spread data results from directly spreading transmission data with a spreading code. The spread data is distributed into two sequences of data at a specified timing synchronized with the reference clock. First and second pulse shaping signals are generated at a specified timing synchronized with the reference clock. A cosine carrier and a sine carrier are generated. One of the two sequences of data is multiplied by the first pulse shaping signal and the cosine carrier. The other of the two sequences of data is multiplied by the second pulse shaping signal and the sine carrier. Outputs from the multiplications are synthesized to acquire an output signal for transmission.

Abstract: A wide-band amplifier having a flat amplification characteristic over a wide frequency bandwidth, being prevented from degrading due to parasitic capacitance, and being short in group delay time. The wide-band amplifier includes a band-pass filter made of an LC parallel resonant circuit and an LCR series resonant circuit and provided in parallel as a load for a current output amplifier device. The band-pass filter has a plurality of poles as well as zeros provided therebetween in the s-plane, thereby improving a characteristic flatness in a passband. The output terminal of the amplifier device serves as an output terminal for the amplifier, so that the problem of group delay does not occur. A capacitance element between the output terminal of the amplifier and GND absorbs parasitic capacitance as part of constants, thereby preventing degradation of the frequency characteristic.

Abstract: A multiband OFDM_UWB transmitting and receiving apparatus is provided in Low-IF configuration to solve problems attributed to a direct-conversion transmitting and receiving apparatus. A Low-IF receiver performs sorting by rotating a sub-carrier after FFT to eliminate the need for frequency conversion using a second local signal and uses the same AD conversion clock as that for a direct conversion receiver. An FFT-free preamble can be detected by using a sequence resulting from previously multiplying an original preamble pattern and an IF frequency together.

Abstract: A reference frequency of 4224 MHz is divided into ½ to obtain a sampling frequency of 2112 MHz, and further the frequency division into ½ is sequentially performed and the values of three bits outputted by the ½, ¼ and ? frequency division are decoded in response to frequency selection. From one set of nonlinear 2-bit DA converters which output amplitudes {?1.7, ?0.7, 0.7, 1.7} using these decoded values as input, complex amplitudes corresponding to eight phases in a complex plane are outputted, so that complex sine waves are generated. Using these complex sine waves, the frequency switching is performed. Center frequencies of respective bands can be obtained without a phase error or an amplitude error.

Abstract: For the purpose of efficient transmission based on the UWB system, first and second baseband waveforms are generated at a cycle equivalent to an integral multiple of a carrier to have a specified phase difference from each other. The first baseband waveform is multiplied by the carrier and a first transmission data sequence to acquire a first transmission waveform. The second baseband waveform is multiplied by a phase shifted carrier and a second transmission data sequence to acquire a second transmission waveform. The first transmission waveform is mixed with the second transmission waveform to acquire a transmission signal. The transmission signal is transmitted as a ?/2 shift BPSK signal to transmit a UWB signal. Selecting the baseband waveforms and the carrier makes it possible to configure the transmission band and easily provide division multiplexing transmission.

Abstract: For the purpose of efficient transmission based on the UWB system, first and second baseband waveforms are generated at a cycle equivalent to an integral multiple of a carrier to have a specified phase difference from each other. The first baseband waveform is multiplied by the carrier and a first transmission data sequence to acquire a first transmission waveform. The second baseband waveform is multiplied by a phase shifted carrier and a second transmission data sequence to acquire a second transmission waveform. The first transmission waveform is mixed with the second transmission waveform to acquire a transmission signal. The transmission signal is transmitted as a ?/2 shift BPSK signal to transmit a UWB signal. Selecting the baseband waveforms and the carrier makes it possible to configure the transmission band and easily provide division multiplexing transmission.

Abstract: A small-sized switch apparatus for switching between signal paths of at least first, second and third frequency bands is capable of handling high-powered high-frequency signals with a relatively low control voltage and is useful in a mobile terminal apparatus. A first signal terminal of a diplexer is connected to an antenna terminal, and a second signal terminal is connected to a high-frequency switch via a filter. A third signal terminal of the diplexer is connected to a high-frequency switch via a second filter. The high-frequency switch has PIN diodes as switching devices, and performs switching between a global system for mobile communications transmission signal and a global system for mobile communications reception signal.

Abstract: A small-sized switch apparatus for switching between signal paths of at least first, second and third frequency bands is capable of handling high-powered high-frequency signals with a relatively low control voltage and is useful in a mobile terminal apparatus. A first signal terminal of a diplexer is connected to an antenna terminal, and a second signal terminal is connected to a high-frequency switch via a filter. A third signal terminal of the diplexer is connected to a high-frequency switch via a second filter. The high-frequency switch has PIN diodes as switching devices, and performs switching between a global system for mobile communications transmission signal and a global system for mobile communications reception signal.

Abstract: An objective is to perform pulse modulation so as to allow for an effect of inter-symbol interference in the UWB communication. For this purpose, a reference clock signal is generated. Spread data is sequentially output at a specified timing synchronized with the reference clock. In this case, the spread data results from directly spreading transmission data with a spreading code. The spread data is distributed into two sequences of data at a specified timing synchronized with the reference clock. First and second pulse shaping signals are generated at a specified timing synchronized with the reference clock. A cosine carrier and a sine carrier are generated. One of the two sequences of data is multiplied by the first pulse shaping signal and the cosine carrier. The other of the two sequences of data is multiplied by the second pulse shaping signal and the sine carrier. Outputs from the multiplications are synthesized to acquire an output signal for transmission.

Abstract: A small-sized switch apparatus for switching between signal paths of at least first, second and third frequency bands is capable of handling high-powered high-frequency signals with a relatively low control voltage and is useful in a mobile terminal apparatus. A first signal terminal of a diplexer is connected to an antenna terminal, and a second signal terminal is connected to a high-frequency switch via a filter. A third signal terminal of the diplexer is connected to a high-frequency switch via a second filter. The high-frequency switch has PIN diodes as switching devices, and performs switching between a global system for mobile communications transmission signal and a global system for mobile communications reception signal.

Abstract: A small-sized switch apparatus for switching between signal paths of at least first, second and third frequency bands is capable of handling high-powered high-frequency signals with a relatively low control voltage and is useful in a mobile terminal apparatus. A first signal terminal of a diplexer is connected to an antenna terminal, and a second signal terminal is connected to a high-frequency switch via a filter. A third signal terminal of the diplexer is connected to a high-frequency switch via a second filter. The high-frequency switch has PIN diodes as switching devices, and performs switching between a global system for mobile communications transmission signal and a global system for mobile communications reception signal.

Abstract: The present invention suppresses a harmonic component without impairing the phase orthogonality of a pair of complex signals. A polyphase filter is configured so that K pieces of filter circuits, each of which comprises a resistor and a capacitor, are connected and +360/K degrees out of phase with a preceding one. Since counterclockwise rotation occurs when expression is given in terms of the complex plane, a notch occurs in a negative frequency region. A RC value is set so that a notch occurs in a specified frequency band to suppress a (4N+1)-order harmonic component. Since the polyphase filter has a symmetrical structure, an unbalanced component contained in an input signal is eliminated at a frequency that agrees with a pole determined by the RC value. This action improves the orthogonality.