Abstract: In a temperature compensating circuit for an oscillator, a reference voltage is applied between a pair of opposing nodes in a basic bridge circuit having a temperature sensitive element inserted in an arbitrary branch of the bridge. An input terminal of the oscillator is connected between the other pair of opposing nodes, from which nodes an output voltage of the bridge is supplied to the oscillator.

Abstract: A high frequency narrow-band pass multi-mode filter in constructed in such manner that SAW of SSBW resonators are closely disposed to each other on a single piezo-electric substrate to generate different vibration modes of different resonance frequencies, conditions that the resonators are acoustically coupled to each other to cause these vibration modes, are experimentally found, and the above conditions are satisfied by the filter.In order to reduce the ohmic loss of a very narrow common bus bar, the number of strip pairs of electrode in both interdigital transducers (hereinafter referred to as IDT) is minimized and instead reflectors are provided on the both sides of said TDTs to compensate for the reduction of its Q value. A part of the bus bar for the IDT electrodes is formed integral with some or all of gratings of the reflectors, whereby the connecting positions of the grating electrodes with respect to lead terminals can be positioned with a high freedom.

Abstract: A semi-coaxial cavity resonator filter including a plurality of semi-axial cavity resonators, as constructed units, each of which has an adjustable device in which dielectric substrates having a specific dielectric constant of more than 1 are disposed in the gap between the inside wall of a tube-shaped outer conductor and the open end of an inner conductor provided on the inside wall of the outer conductor, and the electrostatic capacitance of the spaces interposed by the dielectric substrates is changed without steps by varying the area of the electrodes on the dielectric substrate. The filter is made by making an individual and predetermined frequency adjustment on the plurality of the semi-axial cavity resonators and then cascade-connecting those resonators in one block through shielding plates having a coupling iris so as to obtain desired filtering characteristics as a bandpass filter.

Abstract: A transmitter having a transmitting phase synchronizing system. To one input of a frequency mixer is applied the output of a phase synchronizing type digital frequency synthesizer, through a first frequency divider. A modulating signal is applied to another input of the frequency mixer. The output from the mixer is connected via a bandpass filter to a phase synchronizing system having in series, along a main route, a phase detector, a lowpass filter, and a voltage controlled oscillator, and thence to an amplifier system. In a feedback route from another outlet of the voltage controlled oscillator to the phase detector is a second fixed frequency divider. The digital frequency synthesizer itself may have a reference oscillator connected in series to a third fixed frequency divider, a second phase detector, a second lowpass filter and a second voltage controlled oscillator, from which a feedback circuit leads back to the phase detector via the first fixed frequency divider and a variable frequency divider.

Abstract: A collision avoidance system for aircraft in which one aircraft is equipped ith an interrogation station having a secondary surveillance radar. Coarse distance measurement is effected either by passive or active distance measurement or by both of them. If the detected distance lies within a certain limit, the output power and/or period of the interrogation signal of the secondary surveillance radar of the subject aircraft is altered so as to effect fine distance measurement. This system can be applied without increasing interference against the existing secondary surveillance radar system by keeping the output power and period of interrogation signal in a minimum required extent. By the same reason the system can keep the interference at a small extent between proximate aircraft, each mounting this collision avoidance system.