摘要:
A hemispherical dielectric resonator is arranged on a metal substrate to make a flat surface of the hemispherical dielectric resonator contact with the metal substrate, and a dielectric wave-guiding channel is connected with a curved side surface of the hemispherical dielectric resonator. Therefore, a dielectric resonance antenna in which the hemispherical dielectric resonator and the dielectric wave-guiding channel are placed on the same metal substrate is obtained. A signal transmitting through the dielectric wave-guiding channel is fed in the hemispherical dielectric resonator, the hemispherical dielectric resonator is resonated, and an electromagnetic wave is radiated. Therefore, the dielectric resonance antenna functions as a wave radiation device.
摘要:
A strip-line filter is provided with upper- and lower-stage resonators having the same electromagnetic characteristics. Each of the resonators has a one-wavelength square-shaped strip line and four open-end transmission lines connected to four coupling points A,C,B and D (or E,G,F and H) of each resonator which are spaced 90 degrees in electric length in that order. The square-shaped strip lines have a pair of parallel coupling lines closely placed in parallel to each other to electromagnetically couple the resonators. Therefore, the filter can be manufactured in a small size. A first microwave resonated in each resonator is electromagnetically influenced by two open-end transmission lines connected to two coupling points A and B (or E and F), and a second microwave resonated in each resonator is electromagnetically influenced by two open-end transmission lines connected to two coupling points C and D (or G and H). Therefore, resonance wavelengths of the microwaves can be longer than a line length of each square-shaped strip line. Also, the resonance wavelengths can be adjusted by trimming the transmission lines. Also, because all constitutional elements are made of strip lines, the filter can be made plane.
摘要:
A frequency converter may be employed in communication equipment such as a portable telephone. The frequency converter includes a differential pair consisting of first and second transistors, a current bypass circuit consisting of third and fourth transistors, and a distortion compensating circuit consisting of fifth and sixth transistors. The distortion compensating circuit decreases an emitter-to-base voltage of the sixth transistor when an emitter current of the first transistor is increased, while it increases an emitter-to-base voltage of the fifth transistor when an emitter current of the second transistor is decreased, non-linearts components of the emitter-to-base voltages of the first and second transistors caused by variations of RF (radio-frequency) signals inputted to the first and second transistors are called decreasing distortion of an output signal of the frequency converter caused by the difference in operating point between the first and second transistors.
摘要:
A master station master antenna having a high directivity in an upper direction, a slave station and a slave antenna having a high directivity in the high direction are arranged on a floor of a room, and furniture is arranged on the floor between the master antenna and the slave antenna. Also, a master reflecting mirror is arranged on a ceiling of the room placed just above the master antenna, and a slave reflecting mirror is arranged on the ceiling placed just above the slave antenna. When an electric wave having a data signal is radiated from the master station, the electric wave radiated in the upper direction passes through a first transmission route and is reflected by the master reflecting mirror toward a horizontal direction. Thereafter, the electric wave passes through a second transmission route near the ceiling and is again reflected by the slave reflecting mirror toward the lower direction. Thereafter, the electric wave passes through a third transmission route and is received by the slave antenna because the slave antenna has a high directivity to receive the electric wave transmitted from the upper direction. Therefore, the data signal can be reliably detected by the slave station without being interrupted by the furniture.
摘要:
A compact dielectric coaxial resonator is provided which includes a dielectric substance having a preselected length along the center line thereof, a groove formed in an end portion of the dielectric substance, a through hole, formed in the dielectric substance, extending through the center line of the dielectric substance, an outer conductive member provided around the periphery of the dielectric substance, and an inner conductive member provided over the groove and the through hole. The groove is exposed to the outside and defined around the center line of the dielectric substance. The through hole is defined to have a given length shorter than the preselected length of the dielectric substance for achieving a small-sized structure with a high unloaded Q which may be manufactured in a simple manner.
摘要:
A push-push oscillator comprises: a resonator having a transmission line and a capacitance connected to the transmission line in parallel; an oscillator for producing two outputs having an antiphase relation therebetween in response to the resonator; and a differential signal producing circuit for producing a differential signal in accordance with difference between these two outputs. These outputs can be obtained from the resonator. The transmission lines comprise strip line or microstrip line which is curved to form an open loop. The transmission line may be made of a dielectric material and is curved to form an open loop whose both ends are connected to a capacitance. The resonator may further comprise two second transmission lines, each provided to an end of the transmission line, these two second transmission lines facing each other with a given distance therebetween, the distance and length of the second transmission lines being determined such that necessary capacitance is provided. Impedance of each portion of the resonator is determined to miniaturize the resonator. The differential signal producing circuit comprises a balanced to unbalanced converting circuit.
摘要:
A resonator having a strip line, the strip line comprising: a first portion forming an open loop; and two second portions, each provided to each end of the first portion, the second portions facing each other with a given distance therebetween, the distance and length of the second portion being determined such that necessary capacitance is provided. The capacitor is provided instead of a discrete capacitor for saving space and for reducing dielectric loss therein. A second resonator further comprises second and third capacitor having a semicircle strip-line patterns for providing capacitances between ends of the first portion and grounded planes which decrease the resonance frequency so that size of the second resonator are reduced. A third resonator also comprises the first capacitor, but arranged outside of the first portion. Capacitance of the first capacitor can be increased by teeth provided to the second portions. A filter comprises plural third resonators so arranged that coupling between the resonators is obtained by one selected from magnetic-field coupling through the first portions, electromagnetic-field coupling through first and second portions, and electric-field coupling through second portions.
摘要:
The signal transmission lines in a double conversion stage for a double superheterodyne VHF-UHF television receiver are mainly constructed of unbalanced circuits rather than balanced circuits. The circuit arrangement comprises a wide-band amplifier for receiving the incoming carrier frequency, first and second frequency conversion stages, and an intermediate frequency amplifying stage, connections between the wide-band amplifier and the first frequency conversion stage, as well as connections between the second frequency conversion stage and the intermediate frequency amplifying stage are achieved by means of unbalanced circuits. Each of the first and second frequency conversion stages comprises a mixer constructed of a single balanced circuit, a local oscillator and an unbalanced/balanced conversion circuit interposed therebetween. A filter means, having a band-pass filter, and a low-pass filter interposed between the first and second frequency conversion stages effectively blocks spurious signals.
摘要:
In a digital communication system such as a mobile radio system, fading distortion is compensated with a raised precision. In a transmitter, pilot signals are regularly inserted in the information signals. The amplitude of the pilot signals are set larger than the maximum possible amplitude of the information signals. The modulation scheme of the pilot signals may be different from that of the information signals. In a receiver, the fading distortion of each of the pilot signals is determined. The fading distortions of the information signals are estimated by interpolation using the determined fading distortion of the pilot signal, and then compensated. The frequency band of each information signal is preferably limited with a roll-off filter with a roll-off coefficient ranging from 0.1 to 0.4.
摘要:
In a digital communication system such as a mobile radio system, fading distortion is compensated with a raised precision. In a transmitter, pilot signals are regularly inserted in the information signals. The amplitude of the pilot signals are set larger than the maximum possible amplitude of the information signals. The modulation scheme of the pilot signals may be different from that of the information signals. In a receiver, the fading distortion of each of the pilot signals is determined. The fading distortions of the information signals are estimated by interpolation using the determined fading distortion of the pilot signal, and then compensated. The frequency band of each information signal is preferably limited with a roll-off filter with a roll-off coefficient ranging from 0.1 to 0.4.