Abstract: A digital signal transmission system including a transmitter and a receiver and capable of transmitting highly efficiently compressed/coded digital video signals and receiving the video signals so that the text of emergency information or the like can be displayed together with video images without once expanding/decoding the digital video signals on the transmitter side. In this system, the multiplexer of the transmitter multiplexes digital video signals and digital audio signals with a digital information signal of text which is produced and has N-level priority information added by the information stream generator, and transmits the multiplex signal to the receiver.

Abstract: A wide-band receiving apparatus used in an FM-FDM type optical image distributing system for transmitting multi-wave and multiple TV signals comprises a circuit for receiving a wide-band input signal containing modified RF signals of two or more different frequency bands and separating the RF signals by the bands; respectively, a first circuit for selecting one of the separated RF signals; a local oscillating circuit for generating a first oscillating signal of a fundamental frequency which is determined based on the frequency range of the selected RF signal; a circuit for producing at least one oscillating signal of a frequency having a predetermined ratio to the fundamental frequency; a second selecting circuit for selecting one of the first oscillating signal and at least one second oscillating signal; a circuit for mixing the selected RF signal with the selected oscillating signal thereby producing an intermediate-frequency signal; and a circuit for demodulating the intermediate-frequency signal.

Abstract: To make it possible to receive a modulated signal which is obtained by suppressing a carrier signal such as a high definition TV signal which is digitally demodulated such as QAM (quadrature amplitude modulation), a receiver of the double super-heterodyne system having the first and second mixers 9 and 13 is a basic constitution. A band pass filter having a flatness in pass band and a small deviation of group delay which will prevent the demodulation of a high definition TV signal from degradation is used a first intermediate frequency filter 11. An SAW filter is used as a second intermediate frequency filter 16. The third mixer 28 for converting a second intermediate frequency signal to a third intermediate frequency signal in frequency is installed and the frequency of the third intermediate frequency signal to be converted is set to a value lower than the frequency of the second intermediate frequency signal.

Abstract: A receiver apparatus having a mixer circuit, an oscillator circuit and a tuner circuit is provided with a trap circuit, interposed between the tuner circuit and the mixer circuit, for removing disturbing mutual modulation waves generated by receiving two or more RF signals. Further, the mixer circuit employs a double balanced mixer structure to offset two or more disturbing mutual modulation waves.

Abstract: Disclosed is a mixer circuit which employs four FET's in a manner so that a source electrode of a first FET and a source electrode of a second FET are connected to a first terminal, a source electrode of a third FET and a source electrode of a fourth FET are connected to a second terminal, a first impedance circuit is connected between the first terminal and the earth, a second impedance circuit is connected between the second terminal and the earth, a first high frequency input terminal is connected through a first switching circuit to a junction between the first impedance circuit and the first terminal, a second high frequency input terminal is connected through a second switching circuit to a junction between the second impedance circuit and the second terminal, a gate electrode of the first FET and a gate electrode of the fourth FET are connected to a third terminal, a gate electrode of the second FET and a gate electrode of the third FET are connected to a fourth terminal, a drain electrode of the first

Abstract: A frequency converter which is capable of rejecting unnecessary signals generated by image signals. The frequency converter has first and second local oscillation circuits which generate local oscillation signals whose frequencies are the same and whose phases are different by 90 degrees from each other. The converter further includes two mixer circuits, and a hybrid coupler. The mixer circuits generate two unnecessary signals whose phases are different by 90 degrees from each other. The hybrid coupler delays one unnecessary signal by a quarter of a wavelength to generate two unnecessary signals whose phases are different by 180 degrees from each other, so that they are cancelled by each other.

Abstract: In a band pass filter of micro strip line structure, an input conductor, an output conductor, a first open end conductor and a second open end conductor are provided. The first and the second open end conductors are located opposite to the input and the output conductors forming narrow gaps between said open end conductors and said input and output conductors. The mutual inductance between the first and the second open end conductors is adjusted by selecting the width of the gap between the first and the second open end conductors.

Abstract: A thick film multilayer substrate using a green ceramic sheet is constructed such that at least three conductor layers and at least two dielectric layers are alternately arranged in turn on the green ceramic sheet substrate, a power supply line being formed in the second conductor layer and thus interposed between the first and third conductor layers in which grounded conductors are formed.

Abstract: A self-oscillation mixer circuit includes a cascade amplifier circuitry which is composed of a first transistor of a common emitter connection having a collector connected to an emitter of a second transistor of a common base connection, a filter circuitry for deriving an intermediate frequency signal and a resonance circuit adapted to resonate at a local oscillation frequency being connected to the collector of the second transistor and a feedback circuitry connected between the resonance circuitry and the emitter of the first transistor.

Abstract: A magnetic brush developing device comprising a developing roller including a cylindrical stationary magnet and a sleeve rotatably mounted around the magnet, the developing roller being disposed adjacent the surface of a latent image bearing member, the cylindrical magnet having a developing magnetic pole facing the surface of the latent image forming member and transporting magnetic poles respectively disposed above and below the developing magnetic pole in adjacent relation thereto, the transporting magnetic poles being narrower in width than and having an opposite polarity to the developing magnetic pole.

Abstract: In a magnetic brush developing device, the improvements comprising a plurality of developing rollers consisting of cylindrical stationary magnets each having a developing magnetic pole and disposed in facing relation to the surface of latent image forming member, and cylindrical sleeves rotating around each of said stationary magnets, said plurality of developing rollers being arranged along the surface of said latent image forming member in a manner that the developing magnetic poles have alternately opposite polarities, whereby delivery and receipt of the developing agent between the adjacent developing rollers are effected between the developing magnetic poles of adjacent developing rollers.

Abstract: A magnetic brush developer for use in electrophotographic copiers or the like, the developer comprising a magnet support shaft fixedly mounted with respect to the copier; a hollow, cylindrical magnet fixedly mounted on the support shaft; a hollow cylinder rotatably, concentrically mounted about the cylindrical magnet, the cylinder having at least one side, the one side including an annular support member for the cylinder where the support member is rotatably mounted on the magnet support shaft and projects inside of the cylinder to thereby provide a compact arrangement for the developer.

Abstract: A device for use in an electrophotographic duplicator employing a sensitive member comprising a temperature-dependent sensitive material whose static charge characteristic varies with the surface temperature thereof, the sensitive member bearing an electrostatic latent image having an image region and a background region, the device comprising a developing electrode disposed at the periphery of the sensitive member for effecting uniform development of the image region; temperature sensitive means disposed in the vicinity of the sensitive member responsive to the surface temperature of the sensitive member for generating a bias potential for the developing electrode, the developing electrode being so controlled by the bias potential that the bias potential is always maintained at a value greater than the value of the potential of the background region even when the temperature at the surface of the sensitive material decreases substantially thereby necessitating a substantial increase in the bias potential whe

Abstract: A magnetic brush developing device including a plurality of developing rollers each consisting of a cylindrical stationary magnet and a cylindrical sleeve rotating around said magnet, said plurality of developing rollers being disposed among the surface of a latent image forming member, wherein said cylindrical stationary magnets each have (a) a developing magnetic pole positioned in a portion facing the surface of latent image forming member, (b) a transporting magnetic pole positioned rearwardly of said developing magnetic pole in the travelling direction of a developing agent and having an opposite polarity to that of the developing magnetic pole, and (c) an auxility transporting magnetic pole positioned in a portion facing the preceding developing roller in the travelling direction of developing agent and having a polarity identical with the polarity of said transporting magnetic pole, said developing magnetic poles having the identical polarity and thus delivery and receipt of the developing agent betwee

Abstract: A container for a mechanical filter is provided in which the internal pressure is reduced to prevent propagation in the air of sound waves to thereby prevent deterioration of the filter characteristics. A recess with an aperture therethrough is formed in one of the walls of a metal casing which constitutes the container. Further, an adhesive tape-like member is disposed on the surface of the recess in such a manner as to cover the aperture. After the casing has been evacuated through the aperture, hermetic sealing means is provided on the adhesive tape-like member within the recess.

Abstract: In a mechanical filter, a pair of transducer elements of truncated circular cross-section are disposed at the input and output sides respectively, and they are mechanically connected in cascade to each other by means of a coupler member. The areas of the truncated cross-section of the transducer elements are made different from each other. Between said pair of transducer elements may be provided one or more resonator elements each provided with a recess and connected to each other and to said transducer elements by said coupler member. Each of the transducers and resonators are mounted on a mount base plate by means of a bent wire-like support member having a pair of legs. The foregoing mechanical filter is accommodated in a container which is pressure-reduced and hermetically sealed.