Abstract: A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (2): wherein R1 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, a nitro group or a halogen atom, and X is a halogen atom, the method characterized by reacting a 1,2-benzisothiazol-3-one represented by the general formula (1): wherein R1 is the same group as the R1 defined in the above general formula (2), with a thionyl halide in a polar solvent. The 3-halo-1,2-benzisothiazole obtainable according to the method of the present invention is suitably used as production raw materials and the like for a medicament and the like.

Abstract: A filter circuit according to the present invention includes a voltage-current conversion unit that converts a voltage signal input to an input end to a current signal, a capacitor group that is made up of a plurality of capacitors, where the current signal output from the voltage-current conversion unit is sequentially input to each capacitor at every cycle, a first switch that connects a set of capacitors to which the current signal is input with each other and adds charges accumulated in the set of capacitors together, and a second switch that connects at least one capacitor of the set of capacitors to an output end after charges are added by the first switch.

Abstract: There is provided a communication system including a transmitter and a receiver, each including a communication circuit unit that processes a high-frequency signal for transmitting data, a band-pass filter, and a high frequency coupler, a distributed constant line connecting the high frequency coupler and the band-pass filter of the transmitter, and a distributed constant line connecting the high frequency coupler and the band-pass filter of the receiver, wherein an electrical length of the distributed constant line of the transmitter is different from an electrical length of the distributed constant line of the receiver.

Abstract: There is provided a filter circuit including a passive mixer circuit, and a passive switched capacitor circuit that is connected to a rear stage of the passive mixer and includes a flying capacitor. The passive mixer circuit generates a baseband signal by multiplying an input signal supplied from a predetermined signal source impedance by each local oscillation signal and outputs the baseband signal to the passive switched capacitor circuit, the passive switched capacitor circuit performs predetermined filtering on the baseband signal supplied from the passive mixer circuit and outputs the processed baseband signal, and a capacitance of the flying capacitor of the passive switched capacitor circuit is a capacitance by which input impedance of the passive mixer circuit is matched to the signal source impedance.

Abstract: There is provided a communication device including: a high frequency coupler; a band-pass filter; a switching mechanism that switches an electrical length a transmission line between the high frequency coupler and the band-pass filter; a communication unit that receives hardware information of other end of communication before establishing a communication connection; and a control unit that controls switching of the electrical length of the transmission line according to the received hardware information of the other end of communication by using the switching mechanism with or after establishing a communication connection.

Abstract: There is provided a filter circuit that includes: a flying capacitor which maintains polarity when switching from an input terminal to an output terminal, and the polarity of which is reversed when switching from the output terminal to the input terminal; a first capacitor that is provided in parallel with the flying capacitor, at the input terminal of the flying capacitor; and a second capacitor that is provided in parallel with the flying capacitor, at the output terminal of the flying capacitor. The flying capacitor is switched from the input terminal to the output terminal with a delay of a predetermined time after the switching from the output terminal to the input terminal, and the flying capacitor is switched from the output terminal to the input terminal with a delay of a predetermined time after the switching from the input terminal to the output terminal.

Abstract: There is provided a filter circuit including a passive mixer circuit, and a passive switched capacitor circuit that is connected to a rear stage of the passive mixer and includes a flying capacitor. The passive mixer circuit generates a baseband signal by multiplying an input signal supplied from a predetermined signal source impedance by each local oscillation signal and outputs the baseband signal to the passive switched capacitor circuit, the passive switched capacitor circuit performs predetermined filtering on the baseband signal supplied from the passive mixer circuit and outputs the processed baseband signal, and a capacitance of the flying capacitor of the passive switched capacitor circuit is a capacitance by which input impedance of the passive mixer circuit is matched to the signal source impedance.

Abstract: A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (2): wherein R1 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkoxycarbonyl group having 2 to 5 carbon atoms, a nitro group or a halogen atom, and X is a halogen atom, the method characterized by reacting a 1,2-benzisothiazol-3-one represented by the general formula (1): wherein R1 is the same group as the R1 defined in the above general formula (2), with a thionyl halide in a polar solvent. The 3-halo-1,2-benzisothiazole obtainable according to the method of the present invention is suitably used as production raw materials and the like for a medicament and the like.

Abstract: There is provided a filter circuit that includes: a flying capacitor which maintains polarity when switching from an input terminal to an output terminal, and the polarity of which is reversed when switching from the output terminal to the input terminal; a first capacitor that is provided in parallel to the flying capacitor, at the input terminal of the flying capacitor; and a second capacitor that is provided in parallel to the flying capacitor, at the output terminal of the flying capacitor. The flying capacitor includes a variable capacity element such that capacity becomes smaller when switching from the input terminal to the output terminal and capacity becomes larger when switching from the output terminal to the input terminal.

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: There is provided a communication device including: a high frequency coupler; a band-pass filter; a switching mechanism that switches an electrical length a transmission line between the high frequency coupler and the band-pass filter; a communication unit that receives hardware information of other end of communication before establishing a communication connection; and a control unit that controls switching of the electrical length of the transmission line according to the received hardware information of the other end of communication by using the switching mechanism with or after establishing a communication connection.

Abstract: A charge domain filter circuit includes a first signal output portion, a second signal output portion, and an adder portion. The first signal output portion outputs a first signal that is sampled at a specified time interval. The second signal output portion outputs a second signal that is sampled at the same time interval as the first signal and at a different time. The adder portion adds the first signal and the second signal together and outputs the result. The second signal output portion is capable of selecting the time to sample the second signal from among a plurality of times.

Abstract: A filter circuit includes a voltage-current conversion portion that converts a voltage signal input to an input terminal to a current signal, a first capacitor unit formed by a plurality of capacitors, and in which a current signal output from the voltage-current conversion portion is sequentially input to the capacitors, the unit adding and outputting electric charges of a group of capacitors to which the current signal is input, a second capacitor unit formed by a plurality of capacitors, and in which a current signal output from the first capacitor unit is sequentially input to the capacitors, the unit adding and outputting electric charges of a group of capacitors to which the current signal is input, and a plurality of connection nodes that respectively connect a given capacitor in the first capacitor unit and a capacitor in the second capacitor unit.

Abstract: There is provided a communication system including a transmitter and a receiver, each including a communication circuit unit that processes a high-frequency signal for transmitting data, a band-pass filter, and a high frequency coupler, a distributed constant line connecting the high frequency coupler and the band-pass filter of the transmitter, and a distributed constant line connecting the high frequency coupler and the band-pass filter of the receiver, wherein an electrical length of the distributed constant line of the transmitter is different from an electrical length of the distributed constant line of the receiver.

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: There is provided a filter circuit that includes a flying capacitor and a capacitor that is provided in parallel with the flying capacitor, between an input terminal and an output terminal of the flying capacitor. As the capacitor that has a predetermined capacity is provided between the input terminal and the output terminal of the flying capacitor, it is possible to provide steep attenuation characteristics in the filter circuit provided with the flying capacitor.

Abstract: A wide-band amplifier includes a band-pass filter made of an LC parallel resonant circuit and an LCR series resonant circuit. Both the LC parallel resonant circuit and the LCR series resonant circuit are connected in parallel to a current amplifier device. The band-pass filter has a plurality of poles as well as zeros provided therebetween in the s-plane, where some of the zeros are situated at locations other than the s-plane origing to improve 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 to prevent degradation of the frequency characteristic.

Abstract: An amplifier is provided which includes: a first variable capacitance device of which capacitance is variable, a second variable capacitance device of which capacitance is variable, electrically connected to the first variable capacitance device, and of an inverse conductivity type from the first variable capacitance device, and a first input unit for selectively inputting a bias voltage and a voltage signal to the first variable capacitance device and the second variable capacitance device, wherein, in the event that the bias voltage and the voltage signal are input to the first variable capacitance device and the second variable capacitance device, the capacitance of the first variable capacitance device and the second variable capacitance device is taken as a first value, and wherein the voltage signal is amplified with the capacitance of the first variable capacitance device and the second variable capacitance device as a second value smaller than the first value.

Abstract: To provide a charge sampling filter circuit and a charge sampling method. A charge sampling filter circuit includes a first capacitor that samples an input signal, and in which at least a portion of electric charge stored in the first capacitor by sampling is output to a second capacitor that is connectable with the first capacitor. The charge sampling filter circuit is characterized by including a switching portion that switches a circuit mode including a sampling mode that causes the first capacitor to sample the input signal, and an output mode that causes the first capacitor and the second capacitor to be connected. A capacitance value of the first capacitor in the output mode is set to be lower than the capacitance value in the sampling mode.

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.