Abstract: A multi-resonant antenna device having good VSWR characteristics even in the UWB band, and a wireless communication apparatus including the antenna device are provided. The antenna device includes a substrate, an antenna main body surface-mounted at a corner of the substrate, and slits. The antenna device resonates at two different resonance frequencies. The slits are arranged to bring a VSWR value at a frequency between the two resonance frequencies closer to VSWR values at the two resonance frequencies. The slits include capacitive adjustment slit portions and inductive adjustment slit portions. The slits are provided in an area where the density of a current flowing on ground conductor surfaces is highest. The slits are arranged perpendicularly or substantially perpendicularly to a direction of this current. Specifically, the slits are provided near and parallel or substantially parallel to an open end of the radiating electrode portion.

Abstract: A communication system includes a modulating circuit to increase the amount of information to be transmitted, a transmitting apparatus capable of easily generating a desired waveform even for any very short wavelets, a receiving apparatus capable of easily separating wavelets even if the intervals thereof are narrow. The modulating circuit includes clock generating, transmission signal generating, control signal generating, delay and wavelet generating parts. The clock generating part generates a clock signal at predetermined time interval “Tp”. The transmission signal generating part generates a transmission signal at interval “Tp”. The control signal generating part outputs a control signal of a predetermined duration based on the clock signal. The delay part generates the control signal as a delay signal that has been delayed by a delay amount based on the transmission signal. The wavelet generating part generates a wavelet at the generation timing of the delay signal.

Abstract: A pulse modulation type transmitter apparatus and a pulse modulation type receiver apparatus wherein both a fast synchronization establishment and a low power consumption of a synchronizing part can be achieved at the same time and wherein the data transmission/reception can be performed soon after a commencement of communication, and further a fast data transmission and a low power consumption can be achieved. A first template signal (1006), which is generated based on a separately transmitted RF frame synchronization signal (1005), is used to generate a frame synchronization signal (1009), and a second frame synchronization timing adjusting part (150) is used to synchronize the frame synchronization signal (1009) with a received RF data signal (1004). Then, a synchronization detection is performed, whereby a prompt pulse acquisition and a prompt pulse phase acquisition can be achieved.

Abstract: A master side communication apparatus and a slave side communication apparatus wherein the structure of a receiving part of the slave side communication apparatus is simplified to achieve a reduced size, a reduced power consumption and a reduced cost. The master side communication apparatus performs a communication in synchronism with the slave side communication apparatus having no synchronization timing adjusting function. A transport signal generating timing adjusting part of the master side communication apparatus acquires, from the slave side communication apparatus, synchronization signal generation timing information used when the slave side communication apparatus receives the transport signal from the master side communication apparatus. The transport signal generating timing adjusting part varies and adjusts, based on the acquired information, the transmission timing of the signal to be transmitted to the slave side communication apparatus.

Abstract: A multi-resonant antenna device having good VSWR characteristics even in the UWB band, and a wireless communication apparatus including the antenna device are provided. The antenna device includes a substrate, an antenna main body surface-mounted at a corner of the substrate, and slits. The antenna device resonates at two different resonance frequencies. The slits are arranged to bring a VSWR value at a frequency between the two resonance frequencies closer to VSWR values at the two resonance frequencies. The slits include capacitive adjustment slit portions and inductive adjustment slit portions. The slits are provided in an area where the density of a current flowing on ground conductor surfaces is highest. The slits are arranged perpendicularly or substantially perpendicularly to a direction of this current. Specifically, the slits are provided near and parallel or substantially parallel to an open end of the radiating electrode portion.

Abstract: A transmitting apparatus, receiving apparatus and communication system are disclosed, and great improvement in an S/N ratio, preventing an actual throughput from decreasing, and preventing the number of circuits for synchronizing spread spectrum signals from increasing can be expected at the receiving apparatus side. The transmitting apparatus includes a pulse generating circuit, pulse repetition cycle determining circuit, peak power determining circuit, and modulator. The pulse generating circuit generates pulse strings, pulse repetition cycle determining circuit determines, based on a clock signal, a pulse repetition cycle of the pulse string generated by the pulse generating circuit. The peak power determining circuit determines a pulse peak power of the pulse string. The modulator modulates the pulse string with transmission data, and then generates a transmission signal.

Abstract: A plate-like radiation element is arranged above a ground plane with a space from the ground plane. The radiation element 2 resonates at a predetermined low-frequency wavelength ?1 and a predetermined high-frequency wavelength ?2. A feeding portion for being connected to a feed circuit and a pair of short-circuit portions are provided on peripheral edge portions of the radiation element. The feeding portion is provided on one end of the radiation element. The pair of short-circuit portions for being connected to a ground plane are arranged in areas positioned at opposite sides, on both sides of the feeding portion along peripheral edge directions of the radiation element, where the voltages of high-frequency resonance supplied from the feeding portion to the individual short-circuit portions are zero. The short-circuit portions extend toward the ground plane for being connected to the ground plane. At the other end opposite to the feeding portion of the radiation element is an open end.

Abstract: An impulse radio communication device includes a wave detector for generating a detected signal, a switching section for selecting either a received signal or the detected signal in accordance with an external control signal and outputting it as a demodulation target signal, a reference waveform generating section synchronized with the demodulation target signal and generating a reference waveform signal having a different waveform in accordance with the external control signal, a demodulator for generating a demodulated signal from the demodulation target signal in accordance with the reference waveform signal, and a decoding section for decoding received data from the demodulated signal. This impulse radio communication device switches the demodulation target signal and the reference waveform signal simultaneously in accordance with a receiving and synchronizing state.

Abstract: A pulse modulation type transmitter apparatus and a pulse modulation type receiver apparatus wherein both a fast synchronization establishment and a low power consumption of a synchronizing part can be achieved at the same time and wherein the data transmission/reception can be performed soon after a commencement of communication, and further a fast data transmission and a low power consumption can be achieved. A first template signal (1006), which is generated based on a separately transmitted RF frame synchronization signal (1005), is used to generate a frame synchronization signal (1009), and a second frame synchronization timing adjusting part (150) is used to synchronize the frame synchronization signal (1009) with a received RF data signal (1004). Then, a synchronization detection is performed, whereby a prompt pulse acquisition and a prompt pulse phase acquisition can be achieved.

Abstract: A master side communication apparatus and a slave side communication apparatus wherein the structure of a receiving part of the slave side communication apparatus is simplified to achieve a reduced size, a reduced power consumption and a reduced cost. The master side communication apparatus performs a communication in synchronism with the slave side communication apparatus having no synchronization timing adjusting function. A transport signal generating timing adjusting part of the master side communication apparatus acquires, from the slave side communication apparatus, synchronization signal generation timing information used when the slave side communication apparatus receives the transport signal from the master side communication apparatus. The transport signal generating timing adjusting part varies and adjusts, based on the acquired information, the transmission timing of the signal to be transmitted to the slave side communication apparatus.

Abstract: An impulse radio communication device includes a wave detector for generating a detected signal, a switching section for selecting either a received signal or the detected signal in accordance with an external control signal and outputting it as a demodulation target signal, a reference waveform generating section synchronized with the demodulation target signal and generating a reference waveform signal having a different waveform in accordance with the external control signal, a demodulator for generating a demodulated signal from the demodulation target signal in accordance with the reference waveform signal, and a decoding section for decoding received data from the demodulated signal. This impulse radio communication device switches the demodulation target signal and the reference waveform signal simultaneously in accordance with a receiving and synchronizing state.

Abstract: A communication system includes a modulating circuit to increase the amount of information to be transmitted, a transmitting apparatus capable of easily generating a desired waveform even for any very short wavelets, a receiving apparatus capable of easily separating wavelets even if the intervals thereof are narrow. The modulating circuit includes clock generating, transmission signal generating, control signal generating, delay and wavelet generating parts. The clock generating part generates a clock signal at predetermined time interval “Tp”. The transmission signal generating part generates a transmission signal at interval “Tp”. The control signal generating part outputs a control signal of a predetermined duration based on the clock signal. The delay part generates the control signal as a delay signal that has been delayed by a delay amount based on the transmission signal. The wavelet generating part generates a wavelet at the generation timing of the delay signal.

Abstract: An oil relief valve for lubrication systems for internal combustion engines comprising a valve body having a hollow cylindrical shape, a valve seat provided at a bottom end of the valve body, a valve plug placed in the seat, a port bored in the seat to bring the oil relief valve into fluid communication with a lubrication line which supplies oil from an oil pump to various engine parts to be lubricated, a spring mounted on top of the valve plug and adapted to urge the plug against the seat to close the port, and slits cut in the valve body and provided to bring the valve in fluid communication with an oil pan. The spring has a free length smaller than the distance of the space defined between the valve plug and the top end of the valve body.

Abstract: A valve gear adapted for the four-cycle engine comprises guide portions(s) which is formed on the end surface(s) of crankweb(s) of a crankshaft, and has such a shape folding around the crankshaft with an intersection as to return back to a starting point in two turns; and two interlocking mechanisms provided between the guide portion(s) and the intake and exhaust valves in the engine to open the valves by being guided by the guide portion(s).

Abstract: A 4-cycle engine including a crankshaft connected to a piston and supported at opposite ends by a crankcase for rotation. The crankshaft is formed at one of its two output shaft sections with a groove extending peripherally along the outer peripheral surface of one output shaft section substantially in the form of a endless loop having a cross point. A plurality of followers engaged in the groove have their movements transmitted, through respective linkages, to an exhaust valve and a suction valve respectively. A governor device is located at the other output shaft section and operative to actuate an engine rpm. controller depending on the speed of rotation of the crankshaft.

Abstract: A V-type internal combustion engine in which cylinders each including a cylinder skirt portion projecting into a crankcase are arranged in a V-shape, a governor device is disposed within the crankcase, central axes of the cylinders are offset from each other in an axial direction along a crankshaft supported in the crankcase, and a rotational speed transmission system for transmitting a rotational speed of a governor gear to a governor lever shaft is engages a rearward side of the cylinder skirt portion of a cylinder spaced forward from a rearward most cylinder as viewed among the crankshaft central axis. A single intake manifold is adapted to bridge cylinder heads in a V-bank defined between the cylinders. A carbureter is in fluid communication with the intake manifold. One end of the governor lever shaft is disposed in the V-bank. An intake control for controlling the carbureter in cooperation with one end of the lever shaft is disposed in the vicinity of the carbureter.