Abstract: A magnetic recording and reproducing apparatus comprising a leader block drawing mechanism for drawing a leader block provided at a leading end of a magnetic tape from a tape cartridge having a single reel provided therein and containing the magnetic tape, the leader block drawing mechanism including a cartridge holder movable between a cartridge loading/unloading position and an operative position, a leader block drive to drive the leader block along a predetermined guide path and a control mechanism to control the leader block drive at the loading/unloading position of the cartridge holder means and allow a movement of the leader block drive at the operative position of the cartridge holder.

Abstract: A magnetic tape cleaner comprising a tape scraper engaging a recording face of a magnetic tape to scrape magnetic powder out of the recording face thereof and a magnet to attract and adhere thereto the magnetic powder scraped out of the recording face of the magnetic tape.

Abstract: A digital-analog converter circuit comprising a current output type digital-analog converter and a current/voltage converter connected to an output terminal of the current output type digital/analog converter, the current/voltage converter including bias application means to always apply a bias voltage having a predetermined set value to the output terminal of the digital/analog converter.

Abstract: An optical spot position detection device for an optical disk apparatus able to detect a track position of an optical spot on the recording tracks of an optical disk by dividing a space between centers of adjacent recording tracks into four areas and indicating one of the four areas where the optical spot exists so that a control signal for the optical spot can be provided.

Abstract: A pair of half core blocks, one of which is provided with a groove for providing a prescribed gap depth in a magnetic head, are bonded together to produce a ring core. The ring core is inserted into a slot formed in a top of a magnetic slider and secured in position which provides a precise flush relation between a base end of a half core provided with a groove and the top of the slider. The slider is ground from its bottom to expose the end of the ring core inserted into the slot to produce a head assembly. One side of the ring core portrudes from the slider in the head assembly. When one or more of the head assemblies are mounted on a base block, the protruding side is maintained in contact with a reference upstanding plane provided by a jig for definite positioning of the head assemblies so that gaps in the respective ring cores extends exactly in a running direction of a magnetic tape, thereby preventing azimuth loss.

Abstract: A deglitching circuit suppresses a glitch occurring on an output of a digital/analog converting circuit. The deglitching circuit comprises a detector for detecting a status change that will generate the glitch, of digital data to be inputted into the digital/analog converting circuit, a generator for generating in response to an output of the detector a deglitching pulse for suppressing the glitch, and an operation circuit for canceling with the use of the deglitching pulse the glitch occurring on the output of the digital/analog converting circuit converted from the digital data.

Abstract: A signal processing circuit for an optical disk apparatus to detect a sine wave tracking error signal obtained when an optical spot on an optical disk moves in a direction of a radius of the optical disk and a sine wave whole reflection light quantity signal having a component of phase offset by 90 degrees relative to that of the tracking error signal and to deform the sine wave whole reflection light quantity signal so that a deformed signal is provided which has states of "H" and "L" selected on timing when the whole reflection light quantity signal traverses a center level of its amplitude.

Abstract: A tracking control method in which at least an objective lens within an optical pick-up is so controlled as to be driven in a radius direction of an optical disk having grooves (in a direction traversing track of the optical disk) relative to detectors of two-divided detector means for detecting reflected light quantities of reflected beam obtained by irradiating laser convergent beam of spot diameter defined by .lambda./NA on the optical disk in a manner in which a detection range is divided in the radius direction by estimating a difference information between the detected reflected light quantities, a range of the reflected beam irradiating the detectors being so set that the detectors detect the reflected light quantity equal to each other at a track-on state of irradiation point even though the objective lens moves in the radius direction.

Abstract: A recording and/or reproducing apparatus includes a cartridge receiving holder, a cartridge shutter opening device for opening a laterally slideable shutter of a disc cartridge along with insertion thereof into the holder, a mount base displaceable between a retracted position away from the holder and an operative position in which a head and spindle motor mounted on the base will be made operative with respect to a disc contained in the full-loaded disc cartridge in the holder. The disc cartridge is retained in the full-loaded position in the holder through engagement between a lock lever rotatably mounted on the holder and a notch formed on the side periphery of the disc cartridge. The lock lever is normally biased by a spring to direct outwardly so that the disc cartridge is free from contract with the lock lever during insertion into the holder.

Abstract: A device for opening a shutter of a disc cartridge along with insertion of the disc cartridge into a holder of a recording and/or reproducing apparatus for performing recording and/or reproducing operation is disclosed. The device includes at least one arm member freely rotatable about a pivot provided at one end thereof and having at the other end a first engaging portion adapted to be in engagement with the shutter substantially during insertion of the disc cartridge. A guide means or a slot extending in an oblique direction between the cartridge inserting direction and a direction in which said shutter is slided to open is provided for guiding therealong a second engaging portion of the arm member during first-step advancement of the disc cartridge into the holder from an unloaded position to a half-loaded position, thereby rotating the arm member to open the shutter due to continued engagement thereof with the first engaging portion.

Abstract: A magnetic recording and reproducing apparatus for use with a tape cartridge including a single tape reel having a compact drive and winding reel arrangement.

Abstract: A magnetic recording and reproducing apparatus for use with a tape cartridge includes a holder arrangement operable between a cartridge loading and unloading position and a cartridge operative position. A leader block guide and drive is also carried by the holder to guide and drive a leader block attached to a leading end of a magnetic tape to a winding reel of the apparatus.

Abstract: A tape edge detecting device in which a head unit comprising a writing head and two reading heads, arranged in the widthwise direction of a magnetic tape are provided so that they are movable in the widthwise direction of the magnetic tape in order to detect signals recorded on the magnetic tape, and which also includes a comparison means for comparing the outputs of the reading heads. The edge of the magnetic tape is detected using the output of the comparison means.

Abstract: A digital/analog converting device comprises a first digital/analog converter for converting upper M bits of an input digital signal into a first analog signal; a memory for receiving, as address data, at least a digital signal of lower N bits of the input digital signal to output lower-bit-output-approximate data of S (S>N) bits in response to the address data; a second digital/analog converter for converting digital data at least including the S-bit lower-bit-output-approximate data into a second analog signal; and an analog adder for outputting an added analog signal obtained by adding the first and second analog signals at a predetermined ratio. The S-bit lower-bit-output-approximate data are set such that, supposing a level change of the added analog signal with respect to a change of an LSB of the upper M bits being .DELTA.L, a minimum step increase of the digital signal of lower N bits causes a level of the added analog signal to increase by about .DELTA.L/2.sup.N.

Abstract: A magnetic tape is withdrawn from a tape cassette, wound partly around a rotatable drum with transducer heads through a predetermined wrap angle, and fed along for recording signals on and reproducing signals from the tape with the transducer heads. A pair of skew blocks is fixedly disposed laterally of and near the rotatable drum. When a pair of vertical guide rollers is moved from within a recess defined in the tape cassette to a position near the skew blocks, the vertical guide rollers withdraw the magnetic tape from the tape cassette and hold the magnetic tape against the rotatable drum and the skew blocks. The magnetic tape extending between the skew blocks is skewed by the skew blocks to allow the transducer heads to scan the magnetic tape at a prescribed skew angle.

Abstract: A stationary tape guide, for use with a magnetic tape recorder having an inclined cylinder mounted on a chassis, the tape-guide containing a guide block mounted on the chassis the guide block having the following features. A first tape surface guide inclined with respect to a first reference plane. A second tape surface guide inclined with respect to the first reference plane and located further from the inclined cylinder than the first tape surface guide. A third tape surface guide oriented orthogonal to the first reference plane and located further from are inclined cylinder than the second tape surface guide. A first tape edge guide extending from the guide block beyond a second reference plane defined by the first and second tape surface guides and having a first tape edge contact surface.

Abstract: A magnetic tape is withdrawn from a tape cassette, wound partly around a rotatable drum with transducer heads through a predetermined wrap angle, and fed along for recording signals on and reproducing signals from the tape with the transducer heads. A pair of skew blocks is fixedly disposed laterally of and near the rotatable drum. A pair of vertical guide rollers is movable from a first position in which they are positioned within an opening defined in the tape cassette and behind the tape in the opening to a second position near the skew blocks. When the vertical guide rollers are moved from the first position to the second position, the vertical guide rollers withdraw the magnetic tape from the tape cassette and hold the magnetic tape against the rotatable drum and the skew blocks. The magnetic tape extending between the skew blocks is skewed by the skew blocks to allow the transducer heads to scan the magnetic tape at a prescribed skew angle.

Abstract: This invention relates to a method and an apparatus for measuring optical characteristics such as Mueller matrices or double refraction of an optical disk in which a laser light which is focussed irradiates on an optical disk so that a tracking and a focus of the irradiation light is controlled based on the reflected light from the optical disk while polarization characteristics of the optical disk are measured based on the reflection light.

Abstract: A two-phase encoder circuit for detecting a moving status of a moving article in accordance with first and second detecting signals which are input having a phase offset of 90 degrees and having repeated status of "H" and "L" according to the movement of said moving article, wherein the first detecting signal is taken in synchronization with a clock signal and an output received signal is sequentially output while a delay circuit having an input from at least the received signal outputs a delay signal more delayed than the received signal by less than one period of the clock signal, a pulse signal circuit having an input from at least the received signal outputs, a pulse signal in synchronization with an inversion of status of the received signal and the number of pulses of the pulse signal is counted while counted up or down according to the status of the delay signal with the counting operation being made when the second detecting signal has one status of ""H" and "L".

Abstract: An apparatus for loading a tape cartridge for a magnetic instrument comprising a lever to move a holder holding the tape cartridge from a loading/unloading position, to an operative position, springs to urge the holder from the operative position to the loading/unloading position and to urge the tape cartridge so as to remove it from the holder, a lock to lock the holder to the operative position and a protrusion in the holder to engage the tape cartridge within the holder so as to hold the tape cartridge in the holder whereby the tape cartridge is displaced by the inertia of the tape cartridge from the position of engagement of the tape cartridge with the holder to the position of displacement of the holder by the springs where the tape cartridge is removed by the springs.