Matsushita Electric Industrial Co., Ltd.

Yoichi Sakamoto

Tadao Ohtani

Shigeru Kojima

Nobuyuki Kato

Kiyoshi Kojima

Akihiko Ibata

Isago Konno

Takao Kubo

Masaharu Tsukahara

Tadoa Ohtani

A billet made of a polycrystalline Mn-Al-C alloy magnet which is obtained by plastically deforming a Mn-Al-C alloy for magnet such as by extrusion at a temperature of 530.degree. to 830.degree. C. is used for compressive working. When the billet is hollow, it is entirely or locally compressed along the axis of the hollow billet. On the other hand, when the billet is solid, an outer circumferential portion of the billet is compressed. By the compression, the anisotropic structure of the portion where compressed is changed into an anisotropic structure having a direction of easy magnetization in radial directions. The magnet obtained by the method is also disclosed. The magnet has a radially anisotropic structure or novel structures having two different types of anisotropies therein.

Permanent Mn-Al-C alloy magnets

Anisotropic Mn-Al-C alloy magnets exhibiting excellent magnetic characteristics in multipolar magnetization are described. The magnets are obtained by subjecting a polycrystalline Mn-Al-C alloy magnet, which is rendered anisotropic, to compressive working or extrusion at a temperature of from 530.degree. to 830.degree. C. while keeping restrained at least part of the hollow billet along its length so that the at least part is prevented from suffering compressive deformation until fed into a compressive working region. Permanent magnets obtained by the method are also described.

Method for making permanent magnets of Mn-Al-C alloys

A television synchronous receiver includes: a voltage controlled oscillator; a 90.degree. phase shifter for shifting the phase of the voltage controlled oscillator output by 90.degree.; first and second synchronous detectors for synchronously detecting in-phase and quadrature components of a video carrier signal using the voltage controlled oscillator output and the 90.degree. phase shifter output as synchronous carriers; first and second low-pass filters for filtering low frequency components of the first and second synchronous detector outputs within frequency ranges covering the base band of video and sound intermediate frequency signals; a phase detector for detecting the phase difference between the video carrier signal and the voltage controlled oscillator output from the first and second low-pass filter outputs; a circuit for feeding the phase detector output back to the voltage controlled oscillator; a signal amplifier for amplifying the first low-pass filter output; a signal converter for converting the signal amplifier output into a discrete-time signal; a clock generator for generating clock signals under the control of either television synchronizing signals or color burst signals separated from the signal amplifier output; a discrete-time system for processing the discrete-time signals and a signal reverse converter for reverse converting the discrete-time system output into continuous time signals. The receiver minimizes interference from an adjacent lower channel through the operation of the discrete-time system and generates video signals from the reverse converter without needing a varactor and inductor tuning circuit at the high frequency input section for removing adjacent lower channel signals.

Television synchronous receiver

A television synchronous receiver is provided which is capable of greatly reducing the mixture of the carrier chrominance signal, vestigial luminance signal, and carrier sound signal in a lower adjacent channel into the baseband video signal in a desired channel being received. The television synchronous receiver is composed of a synchronous detector for effecting synchronous detection of a television signal by using a Costas loop, and a low-pass filter for filtering an output from the synchronous detector. The receiver also has an A/D converter for converting a baseband video signal contained in an output from the low-pass filter into a digital signal, and a vertical filter for filtering an output video signal spectrum from the A/D converter, and a D/A converter for converting an output from the vertical filter into a video signal, so that, irrespective of the fact that a television broadcast wave contains a lower adjacent channel, the converted luminance signal, carrier chrominance signal, and carrier sound signal of the lower adjacent channel produced by the synchronous detector are prevented from being mixed.

Permanent Mn-Al-C alloy magnets and method for making same

A synchronous receiver having a reduced pull-in time without requiring a frequency error detection circuit using a differentiator is provided with a voltage-controlled oscillator, a 90.degree. phase shifter which shifts the phase of an output from the voltage controlled oscillator by an angle of 90.degree., first and second synchronous detectors which detect an in-phase component and a quadrature component of a video carrier signal, a phase detector for detecting a phase difference between the video carrier signal and the output of the voltage-controlled oscillator, a first low pass filter for filtering the output of the phase detector, a frequency discriminator for discriminating the frequency of an audio IF signal generated by the first synchronous detector and a second low pass filter for filtering the output of the frequency discriminator. The output of the first and second low pass filters are fed back to the voltage-controlled oscillator so that the phase difference between the output of the first and second synchronous detectors is made equal to 0.

A television synchronous receiver is arranged to maintain a 90.degree. phase difference in the broad frequency band of a TV broadcast between a local oscillator signal and another local oscillator signal. This allows a pair of synchronous detectors to detect the in phase components and quadrature components of a received television broadcast signal. A Costas loop is utilized in the generation of the 90.degree. phase difference.

There is provided a method of producing a manganese-aluminum-carbon alloy magnet, including the steps of preparing a polycrystalline Mn-Al-C alloy magnet having a specified direction of easy magnetization and subjecting the magnet to compressive working in that direction at a temperature of 550.degree. to 780.degree. C., the degree of said compressive working being equivalent to a logarithmic strain of .ltoreq.-0.1 and working in said step at least up to a logarithmic strain of -0.1 being free compression.

Method of making permanent magnet of Mn-Al-C alloy

A channel selector characterized in that a plurality of receivers capable of simultaneously performing a receiving operation have a main part of a phase-locked loop frequency synthesizer connected in common thereto, the frequency synthesizer having a programmable frequency divider, a phase comparator, a reference oscillator and a reference frequency divider. The frequency synthesizer is controlled so that a local oscillation frequency corresponding to a determined frequency close to a broadcast signal of a desired receiving channel is synthesized, and one of a plurality of search tuning systems searches and tunes the broadcast signal from the local oscillation frequency.

Channel selector having a plurality of tuning systems

A channel selector for a radio frequency receiver system including a phase locked loop frequency synthesizer for synthesizing a local oscillator frequency corresponding to a closely determined frequency to a transmitted signal of a desired receiving channel, a closed loop search tuning system for varying the local oscillation frequency to provide an automatic frequency control operation of the channel selector, and a control system for enabling either the phase locked loop frequency synthesizer or the closed loop search tuning system to operate so as to control the local oscillation frequency in dependence upon the presence or absence of a received transmitted signal.

Channel selector

A channel selection apparatus wherein digitized voltages corresponding to frequencies of respective channel or boundary frequencies each between respective adjacent channels are Hadamard transformed and stored, which are subsequently inverse-Hadamard transformed to reproduce the digitized voltages, which are then used for channel selection or channel indication.

Channel selection apparatus

A channel selection apparatus of the scanning tuning type in which a tuning frequency is swept by a sweeping voltage to select a given tuning frequency. The sweep of the frequency is controlled for each channel by a control signal stored for each channel in the form of a number of pulses to attain exact instant tuning to a specified channel. An operating unit which compensates for temperature drift of the elements comprising the apparatus is provided to correctly compensate for temperature drift of these elements thereby attaining exact tuning.

Channel selection apparatus including a scanning system

Anisotropic permanent magnets of Mn-Al-C polycrystalline alloy are produced by warm extrusion at a temperature of 530.degree. to 830.degree. C utilizing converging or tapered dies with lubricant interposed between the polycrystalline body and the converging die. With dies of rather small semiangles, alloys with improved magnetic properties with regard to (BH)max, and especially Br are obtained.

Method of making anisotropic permanent magnets of Mn-Al-C alloys

This invention relates to a channel selector provided with a tuning circuit using variable capacitance elements as tuning elements, and has for its primary object the provision of such a channel selector in which bias voltages applied to the variable capacitance elements are preset so that one of these preset bias voltages may be selected by a binary memory circuit and a diode matrix circuit, the selection of the preset voltages disposed in a predetermined sequence may be effected in any desired direction, and one of the bias voltages corresponding to a desired channel may be automatically selected.

Channel selector employing variable capacitance elements for tuning

Magnetic alloys consisting of 68.0.about.73.0 weight % manganese, (1/10 Mn - 6.6).about.(1/3 Mn - 22.2) weight % carbon, the balance aluminum, which show wasp-waisted magnetic hysteresis loops with the ratio of the residual magnetization 4.pi.I.sub.r to the intensity of magnetization 4.pi.I.sub.10000 in a magnetic field of 10000 Oe, I.sub.r /I.sub.10000, falling 0.0.about.0.2.

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Takatsuki, Japan

Yoichi Sakamoto