Abstract: A method for detecting the degree of wear of a magneto-resistance (MR) effect type magnetic head element for reading a magnetic signal by use of a simple structure is disclosed. The degree of wear of an MR head for reading a magnetic signal from a magnetic tape is detected based on a value of resistance of an MR element by a head wear detecting circuit. A signal indicative of the degree of wear of the MR head is supplied to an alarm generating circuit for example, to generate an alarm informing of the life of the MR head.

Abstract: A rotating drum assembly, and a magnetic recording/reproducing apparatus including the rotating drum assembly, are provided. The rotating drum assembly comprises a cylindrical rotating drum; a magneto-resistive head installed on the rotating drum to project at least a part thereof from the outer surface of the rotating drum; and a tape-contact piece installed on the rotating drum so as to project from the outer surface of the rotating drum and to be in contact with the surface of a magnetic tape; the tape-contact piece being formed to have a larger tape-contact width than that of the magneto-resistive head and disposed to be in earlier contact with the magnetic tape than the magneto-resistive head.

Abstract: When a magneto-resistance effect type magnetic head is used as a magnetic tape reproducing head, a contact noise which occurs when a magnetic tape contacts with a magneto-resistance effect element poses a problem. The invention provides a magneto-resistance effect type magnetic head which hardly causes such contact noise and a magnetic signal reproducing apparatus comprising such magneto-resistance effect type magnetic head. A part where a magneto-resistance effect element is formed in a magnetic tape sliding face of the magneto-resistance effect type magnetic head is formed to be a concave of 3 to 30 nm in depth. The contact noise hardly occurs even when the magnetic tape is slid by forming the part where the magneto-resistance effect element is formed into the concave. Still more, almost no output drops due to a spacing loss and a fully large reproduced output may be obtained by defining the depth t1 of the concave within a range of 3 to 30 nm.

Abstract: A rotary drum device and a helical scan magnetic recording/reproducing apparatus employing an MR head as a playback magnetic head. The rotary drum device and the helical scan magnetic recording/reproducing apparatus each include a cylindrically-shaped rotary drum, an inductive magnetic head loaded on the rotary drum so that its portion is protruded from the outer periphery of the rotary drum and a magneto-resistive effect magnetic head loaded on the rotary drum so that its portion is protruded from the outer periphery of the rotary drum. An amount of protrusion from the outer periphery of the rotary drum of the magneto-resistive effect magnetic head is smaller than an amount of protrusion from the outer periphery of the rotary drum of the inductive magnetic head.

Abstract: A magnetic signal reproducing method and apparatus of the helical scan system employing an MR head. The apparatus includes a substantially cylindrically-shaped rotary drum, an inductive magnetic head loaded on the rotary drum, a magneto-resistive effect magnetic head having an amount of protrusion from the rotary drum smaller than that of the inductive magnetic head, a tape sort detection unit, and a tape tension control unit. If information signals are reproduced by the inductive magnetic head, the tape tension of the magnetic tape is decreased by the tape tension control unit and, if information signals are reproduced by the magneto-resistive effect magnetic head, the tape tension of the magnetic tape is increased by the tape tension control unit.

Abstract: A helical scan magnetic recording/reproducing apparatus incorporating an MR head to serve as a reproducing magnetic head is arranged to convert data which is recorded on a magnetic tape into data in the form of DC-free code trains. The magnetic recording/reproducing apparatus is provided with a high-pass filter for attenuating low-frequency components of a reproduced signal detected by the MR head. Moreover, a demodulating circuit is provided which demodulates data in a state before data is converted into the DC-free code trains from the reproduced signal, in which the low-frequency components have been attenuated by said high-pass filter. As a result, noise (thermal asperities) in a low-frequency region caused when the magnetic tape and the MR head are brought into contact with each other is removed so that a reproduced output free from excessive noise is obtained. The high-pass filter is, for example, a rotary transformer mounted on rotational drum.

Abstract: A magnetic signal reproducing apparatus which can lessen fluctuation of reproduced outputs in reproducing magnetic signals recorded in a magnetic tape by a magneto-resistance effect type magnetic head even if a magnetic tape sliding face of the magneto-resistance effect type magnetic head is abraded. A current value of a sense current when a voltage fluctuation level of the sense current caused when a magnetic field in the normal direction is applied to a magneto-resistance effect element of the magneto-resistance effect type magnetic head is equal with a voltage fluctuation level of the sense current caused when a magnetic field in the opposite direction is applied thereto is set to a predetermined value I0. Then, the current value of the sense current supplied to the magneto-resistance effect element of the magneto-resistance effect type magnetic head is set to be greater than I0 in reproducing the magnetic signals recorded in the magnetic tape.

Abstract: A magnetic recording/reproducing apparatus of the helical scan system employing a MR head as a reproducing magnetic head. The magnetic recording/reproducing apparatus includes a MR head 6 and a rotary drum carrying the MR head 6. In reproducing signals from the magnetic tape 7 in accordance with the helical scan system, a magnetic tape 7, having a large number of projections 7c on the tape surface and containing an electrically conductive material in its magnetic layer, is used as a recording medium.

Abstract: A horn speaker system includes a dome-shaped diaphragm, a coil bobbin, a phase equalizer, and a magnetic circuit. The coil bobbin is integral with the dome-shaped diaphragm, and a voice coil is wound on the coil bobbin near a free end thereof. The magnetic circuit coacts with the voice coil for producing forces to actuate the dome-shaped diaphragm. The magnetic circuit includes a cylindrical magnet, a first annular yoke attracted to one end of the cylindrical magnet and having a central opening, a plate cooperating with the first yoke in defining a gap in which the coil bobbin is inserted, and a second yoke attracted to an opposite end of the magnet. The magnet, the first yoke, the first plate, and the second yoke jointly make up a closed magnetic circuit. The phase equalizer serves to keep sounds outputted from the dome-shaped diaphragm in phase. The phase equalizer is mounted on the first yoke and has a plurality of slits defined therein.

Abstract: An acoustic equalizer for use in a speaker unit including a central member in the shape of a generally spherical cone and a plurality of annular members arranged coaxially around the central member, the innermost one of which is partially linked through a linking portion to the central member with an annular vacant space between and each adjacent two of which are partially linked through another linking portion to each other with an annular vacant space between, wherein first ring-shaped end portions of the annular members and a first end portion of the central member surrounded with the first ring-shaped end portions of the annular members are provided to form in its entirety a spherical surface portion for facing a diaphragm member of a speaker unit and second ring-shaped end portions of the annular members opposite to the first ring-shaped end portions and a second end portion of the central member opposite to the first end portion and surrounded with the second ring-shaped end portions of the annular memb

Abstract: An optical recording method and an optical recording apparatus enable recording information on recording tracks substantially corresponding to ideal reference tracks, on an optical recording medium without preformatted tracks. The optical recording medium is scanned by a rotating optical scanning system using a scanning light beam emitted by an external light source to record information on the optical recording medium. Prior to recording the information on the optical recording medium, information recorded on a reference track recording medium provided with ideal reference tracks is reproduced in a tracking control mode to acquire tracking control data and the tracking control data is stored in a waveform memory. In recording information on the optical recording medium, the rotating optical scanning system is controlled on the basis of the previously stored tracking control data so that the scanning spot traces recording tracks corresponding to the ideal reference tracks.

Abstract: A rotating intermediate drum having mounted thereon optical head is made smaller than stationary upper and lower drums in diameter and spiral grooves are formed on the rotating intermediate drum on its surfaces opposing the stationary upper and lower drums. An optical tape is transported in a floated condition relative to a drum circumferential surface owing to a synergy of a dynamic pressure based on the rotation of the rotating intermediate drum and the air exhausted from the spiral grooves. Therefore, an information signal is recorded on and/or reproduced from the optical tape when the optical tape is transported in the floated condition from the head drum having the trilayer structure composed of the stationary upper and lower drums and the rotating intermediate drum therebetween.

Abstract: A rotary drum assembly comprises a stationary member having a stationary cylindrical portion, and a rotary member having substantially the same diameter as that of the stationary member and positioned in the vicinity of the stationary member so as to be relatively stationary to the stationary member. Each of surfaces of the rotary member and the stationary member opposing to each other is formed to have a step structure having a plurality of opposed surfaces, and pump-out type spiral grooves are formed on at least two of the plurality of opposed surfaces of one of the rotary and stationary members.

Abstract: A control circuit for controlling the position of a head in an optical tape recording/reproducing device having a rotary optical head controls the position of the head at the instant that it faces the tape based upon a desired head position derived from a preceding period in which it was facing the tape. A head position error signal is sampled and added to a sample head position signal during a period when the head is facing the tape and is held during the time the head is not facing the tape. The instant the head begins to face the tape once again, this desired value that has been held is applied to the head in order to reduce the pull-in time of the control circuit and provide more time for information recording/reproduction during the time the rotary optical head is facing the tape.

Abstract: A servo control circuit for an image rotator used in an optical tape recording apparatus that employs a rotary tape drum. Pairs of pulse generators and frequency generators are provided on the image rotator and on the tape drum, respectively. Initially, the pulse generators are used for servo control and, upon detecting a phase lock, servo control is subsequently switched over to be controlled by the frequency generators.

Abstract: A rotary optical head apparatus comprises a first rotary member carrying an objective lens and a second rotary member carrying an image rotator. The two rotary members are supported for rotation by means of a single common support shaft so that the axes of rotation of the two rotary members coincide with each other with a high degree of accuracy. Consequently, the linearity of a scanning line of a beam spot which is scanned on an optical magnetic tape is ensured with a high degree of accuracy.