Abstract: A magnetic recording/reproducing apparatus for reproducing data recorded on a recording medium based on the signal read by a head contains a filter circuit which restricts the frequency range of the read signal and allows the low frequency read signal to pass through it, a full wave rectification circuit for full wave rectification of the read signal output from this filter circuit and an integrating circuit for generating a threshold signal of the read signal output from the filter circuit based on the integrated value obtained by integrating the output signal from the full wave rectification circuit when reproducing data and for holding the integrated value at the time of the immediately before data reproduction during the operation other than the data reproducing operation.

Abstract: The present invention provides a search and rescue radar transponder easy in maintenance and checking. In the search and rescue radar transponder of the invention, the transmission electric power of the transmitting circuit 3 leaked at the changeover switch 7 is inputted to the receiving circuit 2, and whether the search and rescue radar transponder operates normally or not is judged by comparing the leaked electric power level detected by the receiving circuit 2 with a prescribed level at the controlling circuit 4. Hereby, the operation-checking of the search and rescue radar transponder proper other than an antenna can be executed by a built-in apparatus, and its maintenance and checking can be executed easily and rapidly.

Abstract: In a sector servo type hard-disk apparatus, in the case where a recording medium is not manufacture-formatted, gain control data is written/read in/from a CSS zone of the recording medium after power is turned on and before the first seek is executed. The write/read of the gain control data in/from the CSS zone is also executed in accordance with a peak level of an output signal from an AGC amplifier.

Abstract: The present invention provides a novel cloth superior in water absorption and oil absorption and besides, in dehydration by using a cloth made of synthetic fibers of low water absorption such as nylon and Tetron as a base and subjecting this base cloth to processing treatment with a composite comprising collagen short fibers chemically modified with oxide of fish oil and polyurethane resin, thereby to impart water absorption property thereto.

Abstract: To prevent a decrease in the window margin due to reproduced signals having asymmetrical waveforms in a magnetic recording and reproducing apparatus, data in which peak shifts occur are recorded in the SYNC regions in the data format for the recording medium in accordance with the recording method. In data read operation, by detecting the data recorded in the SYNC regions, the center of the data window signal is shifted by a desired peak shift amount.

Abstract: A medium access apparatus having low power consumption includes a head driving section, an access section, a power supply section and a control signal generating section. When a medium is rotated, the head driving section causes a head to seek a destination track on the medium in accordance with an input drive signal including step pulses, the number of step pulses corresponding to a number of tracks from a current track, where the head positions, to the destination track. The access section accesses the medium through the head when power is supplied to the access section. The power supply section supplies the power to the access section and stopping the supply of the power in accordance with an input switch control signal. The control signal generating section selectively generates and outputs the switch control signal to the power supply section in accordance with the number of step pulses of the drive signal.

Abstract: An azimuth adjustment disk having first and second areas alternately recorded in a circumfrential direction. Each of the first areas has two azimuth burst signal. The two azimuth burst signals have different azimuths and a first signal wavelength. While each of the second areas has two azimuth burst signals with azimuths corresponding to the bursts of the first areas, but which have a longer wavelength.

Abstract: A magnetic recording/reproducing apparatus includes a control section, a recording section and a medium access section having a head. The control section sets a write mode in response to an input write access command, and outputs write data and density indication data to the recording section. In the write mode, the recording section generates dummy data in accordance with the density indication data and modulates a write current in accordance with the write data and the dummy data subsequent to the write data. The modulated write current is supplied to the medium access section. A value of the write current is determined in accordance with the density indication data, and the write current decays with a time constant while the write current is modulated in accordance with the dummy data. The medium access section write-accesses a medium in accordance with the modulated write current in the write mode.

Abstract: A phased-array antenna is provided with a dummy antenna element and a dummy transmit/receive module for testing the other transmit/receive modules by transmitting test signals to, or receiving test signals from, the other antenna elements in the array. Test signals are transmitted in a test mode that alternates with normal-mode operation. Receive power level and/or phase can be checked. The transmit/receive modules in the array are simplified in structure and improved in reliability due to the elimination of special receive check circuits. Antenna accuracy can also be improved by adjusting the phase shifters in the transmit/receive modules to compensate for variations in transmission phase.

Abstract: Disclosed is a magnetic head apparatus, which comprises a pair of magnetic cores defining a magnetic gap for recording and reproducing information, and grooves in the lateral faces of the magnetic cores, extending at right angles to those faces of the cores which are opposed to a magnetic recording medium or which define the magnetic cores. The grooves determine the width of the magnetic gap. That face of at least one of the magnetic cores which is opposed to the recording medium, is recessed from the remaining portion of the core, so as to cover a width equivalent to the length of the grooves, at the maximum. In the magnetic head of the invention, moreover, a nonmagnetic portion is formed at least on an erase gap, so that the degree of magnetic coupling between the erase gap and the recording medium is lower than that between a read/write gap and the medium. Thus, magnetic induction, which is produced in the erase core when data is read from the medium, is reduced.

Abstract: A magnetic recording/reproduction apparatus includes a first floppy disk drive (FDD) of a preerase head type, which includes a first read/write (R/W) section, and a second FDD of a tunnel erase head type, which includes a second R/W section. A selection signal generating section selectively outputs first and second selection signals generated in accordance with a write command for said first and second FDD. A mode signal supplying section outputs a mode signal generated in accordance with the write command to a write gate (WG) signal generating section. A sync signal generating section generates a sync signal from a read data (RD) signal from the first or second R/W section and sends it to the R/W signal generating section.

Abstract: In a power semiconductor device according to the present invention, a sheet, formed of a soft metal such as Ag, is provided on that portion of a pressing control electrode which is brought into contact with an Al gate electrode of a pellet. By means of this sheet, it is possible both to apply a strong pressing power to the Al gate electrode and to reduce the contact resistance between the two electrode. Since an excessive amount of heat is not produced on account of the contact resistance, the semiconductor device can be protected against being damaged.

Abstract: A magnetic recording/reproduction apparatus of the invention has a magnetic head for reading a vertical magnetically recorded signal, an inplane magnetic recorded signal or a magnetic recorded signal having both a vertical magnetic component and an inplane magnetic component and for supplying a reproduced signal, a first analog signal converting circuit for converting the reproduced signal into an analog inplane reproduced signal when the reproduced signal is a vertical reproduced analog signal, a second analog signal converting circuit for bypassing an inplane analog reproduced signal when the reproduced signal is the inplane reproduced analog signal, and a third analog signal converting circuit for converting the reproduced signal into an inplane reproduced analog signal when the reproduced signal is the inplane reproduced analog signal. The circuits are switched to operate selectively in accordance with the type of signals reproduced from a magnetic recording medium.

Abstract: A data reproduction apparatus is disclosed. Read data, which is a pulse signal, is output from a magnetic disk drive in accordance with the information read by a pre-erase type magnetic head. Based on the read data, a zero pattern detector detects sync data which is constituted by zero data of a predetermined number of bits. A flip-flop outputs a predetermined permit signal using an output signal of the zero pattern detector as a trigger pulse. When the permit signal is output, a PLL circuit locks on the read data to oscillate and output data pulses and window pulses. Upon reception of the data pulses and window pulses. a floppy disk controller reads out data recorded on the magnetic recording medium. From the read data, an erased area detector detects an erased area that is an area, which has been erased by an erase head of the magnetic head and in which no information is written by a read/write head.

Abstract: In a waveform equalizer of the present invention, first and second Hilbert-transform signals are formed from a parallel-reproduced signal, and a desired signal is obtained from these signals by an operational amplifier. The waveform equalizer includes a reflecting section having a plurality of resistors, and a switching section for selecting one of the resistors in accordance with a control signal. Therefore, the waveform equalizer can process a plurality of reproduced signals which have different ratios of the longitudinal signal component to the perpendicular signal component without being affected by inphase noise.

Abstract: This invention concerns a transfer roller prepared by blending short collagen fibers in a rubber matrix for conveying plate-like materials sandwiched between paired rollers. By mixing collagen fibers mechanically in the rubber matrix with no addition of process oil or oil type reinforcing agent, conveyor rollers of a long operation life which show no reduction in the conveying function even when water or oil droplets are deposited to the rollers surface is obtained.

Abstract: A magnetic disc apparatus obtained by housing in a cartridge case, a magnetic disc which is obtained by forming a metallic magnetic sheet on a polymer base and liner sheets. The liner sheet which is installed between the magnetic disc and the cartridge case has an outer diameter which is smaller than the diameter of the magnetic disc, and an inner diameter which is greater than the rotational diameter of an index hole that is prepared on the magnetic disc for detecting the rotational position of the disc. By arranging in this manner, a smooth rotation of the magnetic disc can be accomplished by avoiding the contact with liner sheet of the edges on the outer periphery of the disc that were bent at the time the disc was punched from the magnetic recording medium, and of the edges of the index hole that were bent at the time the index hole was punched.

Abstract: A method of manufacturing a rotor for rotary fluid pumps comprising the steps of assembling a hollow cylindrical body and both side plates to a hollow rotor body, providing the hollow rotor body with a plurality of sockets each receiving a separately fabricated U-shaped vane-groove forming member, and inserting the U-shaped vane-groove forming members into the respective sockets to fix the same to the rotor body by brazing. The U-shaped vane-groove forming member is made from a suitable material as a vane groove itself and sufficiently finished independently from the rotor body.

Abstract: Highly pure p-tertiary-butyl phenol can be prepared from an olefin composition comprising a major amount of at least one isobutylene oligomer and a minor amount of a codimer of n-butene and isobutylene. The reaction of said olefin composition with phenol is carried out in the presence of water and synthetic silica-alumina catalyst at a temperature of 140.degree.-230.degree. C.

Abstract: An acoustic material suitable for use as a speaker edge comprises an expanded plastic and minute collagen fibers wherein the content of the collagen fibers is 15 - 40% based on the weight of the expanded plastic and the length of the fibers is equal to or less than 1 mm.