摘要:
A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the carrier signal and signal indicative of read data. This makes it possible to construct the modulating/demodulating circuit in the form of a digital circuit.
摘要:
An apparatus for positioning a recording or playback head over a rotating recording medium, such as a magnetic disk. When access to a desired track is attempted, the head is quickly moved and placed within a range close to the track under open loop control. When the head enters the range close to the desired track, the head control is switched to servo feed under closed loop control. During the servo feed, the head is moved according to a head position signal representing the actual position of the head, the head position signal being given by a head position detector having a portion moving together with the head. The head is thus directed to a predetermined position according to an error signal corresponding to the deviation of the head position. When the head has passed through the desired position, driving force in the reverse direction is generated and the head is forced back toward the desired position. The head thus oscillates around the desired position but converges to it.
摘要:
An apparatus for positioning a recording or playback head over a rotating recording medium, such as a magnetic disk. When access to a desired track is attempted, the head is quickly moved and placed within a range close to the track under open loop control. When the head enters the range close to the desired track, the head control is switched to servo feed under closed loop control. During the servo feed, the head is moved according to a head position signal representing the actual position of the head, the head position signal being given by a head position detector having a portion moving together with the head. The head is thus directed to a predetermined position according to an error signal corresponding to the deviation of the head position. When the head has passed through the desired position, driving force in the reverse direction is generated and the head is forced back toward the desired position. The head thus oscillates around the desired position but converges to it.
摘要:
A device for tracking a rotary recording medium includes a playback head for reading a signal from any of a plurality of tracks which are formed on the rotary recording medium, which is rotating at a predetermined constant speed, such that a beginning and an end of a recording in each of the tracks coincide with each other, a head support mechanism supporting the head such that the head is movable along the recording medium, an arrangement for detecting an envelope of a signal which is read out of the recording medium by the head, and a controller for controlling the head support mechanism to move the head to a position where a desired one of the tracks is located. An arrangement for detecting a position of the head relative to the recording medium and an arrangement for detecting a rotation phase of the recording medium are provided. The controller controls the head support mechanism to transport the head, while the position detecting arrangement during transport of the head detects positions of the head at which a peak of an envelope is detected in one track at each of a plurality of angles of rotation of the recording medium. The controller produces a means position of those positions of the head detected and, then, controls the head support mechanism to transport the head to the mean position.
摘要:
A data signal is modulated by an exclusive-OR operation applied to a carrier signal and a data signal to be recorded. Demodulation is similarly performed by an exclusive-OR operation applied to the carrier signal and signal indicative of read data. This makes it possible to construct the modulating/demodulating circuit in the form of a digital circuit.
摘要:
A video signal reproducing device in which a reproducing video signal is produced and applied to an external display. A servo reference signal is supplied to a servo loop to synchronize the phase of movement of a motor driving a recording medium. During crossing from track to track the video signal is muted and a compound signal synchronized with the servo reference signal applied to the external display.
摘要:
A tracking apparatus for tracking a track recorded in a rotary recording medium which rotates at a predetermined constant speed has a playback head for sensing a signal out of a desired one of tracks each being provided in the recording medium such that a beginning and an end of recording coincide with each other includes a head transport mechanism for supporting the playback head movably along the recording medium, an envelope detector for detecting an envelope of the signal sensed by the playback head, and a controller for controlling the head transport mechanism to move the playback head to a position where a desired one of the tracks is located. The head transport mechanism includes a head position detector for detecting a position of the playback head on the recording medium. The controller is constructed to control the head transport mechanism to move the head to compute for one of the tracks two different positions where a level of the envelope detected by the envelope detector has a reference value, then compute an intermediate position between the two positions, and then control the head transport mechanism to move the head to the intermediate position. The reference value may be controlled higher when the position of the head is associated with any of the tracks having comparatively large diameters than when it is associated with any of the tracks having comparatively small diameters.
摘要:
A tracking apparatus for a signal reproducing apparatus makes use of a rotating magnetic recording medium, especially when such apparatus reproduces information signals recorded on the medium, such as video signals. The tracking apparatus includes a compensation circuit capable of compensating for the envelope level of the signals sensed by the playback head, so that the dynamic range for which the envelope signal is quantized may be narrower, or the quantum level steps may be smaller, and hence the resolution thereof may be enhanced correspondingly.
摘要:
A recording or reproducing device in which current is supplied to the spindle motor which drives the disk to produce reverse torque in response to a stop signal when the disk is rotating. The beginning of reverse rotation is detected and the supply interrupted in response thereto.
摘要:
An image recording/reproducing apparatus is disclosed which records video signals obtained by photographing an object onto a magnetic recording medium, such as a magnetic disc or the like, or reproduces the video signals recorded on the magnetic recording media. In the image recording/reproducing apparatus, when the object is photographed in a sequential photograph mode, the video signals of the object, as well as, data signals representing the photograph data, including the number of frames to be photographed in one sequential photograph unit and its sequential speed, are recorded onto the magnetic recording medium. During reproduction, the frames recorded in the sequential photograph mode are reproduced at a sequential photograph speed corresponding to the sequential photograph speed of the recording as set forth by the data signals.