Abstract: The present invention is directed to a flat brushless motor utilizable as a warning in a portable communication device. The center of gravity of the rotor assembly is displaced from the center of rotation so that, by the rotation of the unbalanced rotor assembly, vibrations can be generated and the. By elimination of an eccentric or the like for generating the vibrations, a manufacture in a flat and compact size, as well as a reduction in the number of component parts, can be attained.

Abstract: A Colpitts oscillator has an integrated circuit. The integrated circuit includes a transistor having an equivalent large size, a bypass capacitor connected between a collector of the transistor and a ground, a first feedback capacitor connected between a base and an emitter of the transistor, a second feedback capacitor connected between the emitter of the transistor and the ground, and an emitter follower connected to the emitter of the transistor. In a package, a stray reactance and a bonding wire are designed so as to agree with an element value and a Q value which can be used as parts of a resonator. A surface elastic wave resonator disposed outside the integrated circuit is connected between the base of the transistor and the ground. The oscillator is voltage controlled by a variable capacitance diode connected in series with the resonator.

Abstract: A flat brushless motor utilizable as a warning means in a portable communication device such as a pocket bell. The flat brushless motor is such that the center of gravity of the back-yoke (5a) is displaced from the center of rotation so that, by the rotation of the unbalanced back-yoke (5a), vibrations can be generated and, by the elimination of a weight or the like for generating the vibrations, the manufacture in a flat and compact size as well as the reduction in number of component parts can be attained.

Abstract: A paper feeding apparatus for the printer having an intermittent mechanism between a driving motor and both a paper feed roller and a platen. The intermittent mechanism allows both the platen and the paper feed roller to rotate simultaneously and also allows only the platen to rotate while the paper feed roller is suspended, so that a sheet of printing paper is set straight along the platen. When the rotational direction of the driving motor is reversed to reverse that of the platen, the driving motor stops rotating for a limited period. Under such conditions the sheet is fed properly in response to the rotation of the platen, being free from the inertia force of the sheet and from the platen's vibration.

Abstract: A VHF-UHF mixer, which has a balun (14) having a ferrite core (141), a pair of R-C parallel connection circuits (15a) and (15b) connected to output ends of the balun (14), a series connection of two mixing diodes (16a) and (16b) connected across output ends of the R-C parallel connection circuits, and a diplexer (17) consisting of a high pass filter and a low pass filter and connected by its input terminal to center connection point (18) of said series connection of the two mixing diodes, further has a pair of impedance circuits (19a,19b), each being grounded by one ends thereof, consisting of L-C-L series connection circuit, and connected to either input end or output end of the R-C parallel connection circuit.

Abstract: A paper feeder for a printer in which a paper separator roller 15 is rotatably provided in the end portion of a paper holder 12 so that when a paper feed roller 14 is rotated in the paper feed direction, the paper separator roller 15 is arranged to stop at a predetermined position and act similarly to a conventional friction pad, while when the paper feed roller 14 is rotated in the paper return direction, the paper separator roller 15 also rotates in synchronization with the above rotation. By way of vibrating the paper separator roller 15 in the rotational direction or another direction, paper sheets P stacked on the paper holder 12 are vibrated for the purpose of being successively moved in the portion at which the two rollers 14 and 15 are positioned in contact with each other.

Abstract: A paper feeding apparatus for a printer comprises a control means and a drive mechanism for feeding a sheet of paper to a predetermined printing position on the platen. The control means activates the drive mechanism for a predetermined period until a paper detective sensor near the platen detects a leading edge of the sheet. If the paper detective sensor detects no sheet after the predetermined period, a control means repeats the paper feed operation without requiring the operator to give a subsequent driving signal.

Abstract: A microwave band frequency synthesizer comprises first and second phase-locking loops. The first phase-locking loop includes a first voltage controlled oscillator, a variable frequency divider and a first multiplier and generates an output signal whose frequency changes at the rate of a unit frequency change width of the oscillator.

Abstract: Disclosed is a double converter tuner having an input circuit for performing first band control with respect to an input signal, amplifying a band-controlled input signal after automatic gain control is performed, and further performing second band control of a gain-controlled signal, a first IF (intermediate frequency) converter for converting an output generated from the input circuit to a first IF signal having a higher bandwidth than the reception bandwidth of the input signal, a first IF circuit for amplifying an output from the first IF converter, performing third band control and performing a further amplification, a second IF converter for converting an output generated from the first IF circuit to a second IF signal, and a second IF circuit for amplifying an output from the second IF converter, performing fourth band control, and performing another amplification. The first and second IF converters are arranged on different circuit boards to prevent frequency interference therebetween.

Abstract: A microwave frequency synthesizer comprised of a phase-locked loop having a low noise and highly stabilized reference voltage-controlled oscillator and further two phase-locked loops each having a stabilized voltage controlled oscillator, the signal outputs from which are frequency-converted with as small multiplication factors as possible. This frequency synthesizer can minimize the phase noise that may be generated by frequency dividers in a digital system.

Abstract: A compact or miniaturized well-shielded double superheterodyne tuner is provided, wherein an input circuit portion, a first mixing portion, a first intermediate frequency bandpass filter, a second mixing portion and an output circuit portion are mounted in separated casings. The first mixing portion and the second mixing portion are provided on printed boards and each mounted on a bottom plate of the casing. The casings containing the first and second mixing portion are arranged in a manner such that grounded surfaces of the printed boards contained in the casings are arranged face to face. The casing containing the bandpass filter is contacted adjacently to a common face of the face to face casings. Each of the casings containing the input and output circuit portions is located adjacently to each of faces common to the face to face casings and the filter containing casing. Some structual improvements are also provided for simplifying the manufacture and adjustment of the tuner.

Abstract: In a double superheterodyne tuner, the first local oscillator frequency is set to a value higher than the first intermediate frequency, which is set to a value between three and five times the upper limit of the receiving frequency range. With this arrangement spurious signals of at least third or less order can be prevented from occuring in the first intermediate frequency range. The tuner comprises an input filter which attenuates interference signals whose harmonics equal a desired frequency. The second intermediate frequency may be selected such that it is obtained by subtracting the second local oscillator frequency from the first intermediate frequency which is higher than the second local oscillator frequency. As a bandpass filter for passing the first intermediate frequency may be used a coaxial dielectric filter so as to reduce interferences by undesired channel signals.

Abstract: In a voltage-controlled oscillator having an LC resonant circuit including a varactor circuit so that resonant frequency is controlled by a D.C. bias or control voltage applied to the varactor circuit, three or more varactors are connected in series in one embodiment so that a high-frequency voltage applied to the varactor circuit is divided into a plurality. The varactors may be connected in the same direction or opposite direction. In another embodiment, a plurality of series circuits of varactors are connected in parallel to provide the varactor circuit, where each series circuit comprises two or more varactors. A series-parallel connection of a plurality of varactors may be arranged in a matrix. In order to reduce undesirable stray capacitance, some or all varactors are attached to a printed circuit board so that they are normal to the plane of the printed circuit board. In one embodiment an auxiliary printed circuit board is employed so that some varactors are spaced from a main circuit board.