Abstract: A head drum apparatus includes a cylindrical piezoelectric ceramic member formed of a polarized ceramic material and having inner and outer peripheral surfaces. A plurality of electrodes are formed on at least one of the inner and outer peripheral surfaces of the piezoelectric ceramic member. The piezoelectric ceramic member vibrates in response to an AC voltage applied to the electrodes. A cylindrical stationary head drum having an inner peripheral surface and an outer peripheral surface around a portion of which a magnetic tape is wound is caused to vibrate in a bending mode under vibration of the piezoelectric ceramic member. The stationary head drum includes a cylindrical stationary portion, a cylindrical vibratory portion and a cylindrical thin wall portion provided between the stationary portion and the vibratory portion. The piezoelectric ceramic member is coupled to the vibratory portion so that the vibratory portion is caused to vibrate under vibration of the piezoelectric ceramic member.

Abstract: The present invention relates to a rotary drum unit in a helical scan type magnetic recording/reproducing device for use with a video tape recorder, digital audio tape recorded, or the like and is intended to permit the stable run of the tape with highly accurate formation of track patterns. In the helical scan type rotary head drum unit of the present invention, a dislocation of the tape upon the drums having no lead is detected by tape position sensors arranged along a guide line and the rotary head is moved in the axial direction of the drum by driving a dynamic tracking actuator in a manner to correct the deviation of the tape from the guide line.

Abstract: The present invention relates a helical scan-type magnetic recording and reproducing for use in VTR or DAT. This apparatus includes a head scanning mechanism which helically scans the tape (3) that runs in parallel with a reference plane using a head (4) rotatable along a slit (5) formed aslantly relative to the drum shaft (6) between the upper and lower fixed drums (2) and (1) arranged perpendicularly with respect to the reference plane. This mechanism consists of a rotary member (30) disposed concentrically with the upper and lower fixed drums (2) and (1), a linear guide (10) or (31) provided for the rotary member (30) to slide in a direction in parallel with the center of rotation of the rotary member near the head, a head (4) provided for the linear guide (10) or (31), and a cam mechanism (16) or (32) which gives axial displacement to the head (4) in the same direction as the slit (5) relative to the stationary cylindrical members (1), (2), (40).

Abstract: A tape drive mechanism for a video tape recorder and an audio tape recorder. The tape drive mechanism automatically corrects the position of tape in the width-wise direction thereof without mechanically restricting the edge of tape. Sensors (8) and (8) on a tape path detect a dislocation of the tape (7) from a reference running position that may develop in the width-wise direction of the tape (7), a tape guide post (1) for attracting the tape (7) is moved in the width-wise direction of the tape, or inclination of a tape guide post (41) is changed to move the tape (7) in such width-wise direction by means of actuators (2), (42) and (62) that give corresponding displacement based on the values detected by the sensors (8) and (8), or the reel plate (57) is moved in the direction of width of tape to move the tape (7) together with the reel (24). The tape (7) having a small thickness is prevented against vertical movement on the tape path and is permitted to run stably without damaging the edges of the tape.

Abstract: A unidirectional traveling-surface-wave by ultrasonic oscillation is generated on a surface of an oscillator, and a magnetic tape is run in the direction opposite to the traveling direction of the surface wave by pressing the surface of the oscillator against a surface of the magnetic tape.

Abstract: A binary number 2.sup.n can be divided at a rate 2.sup.m by means of shifting down successive digits thereof by m digits, n and m being positive integers which have a relation n>m therebetween. According to the above principle, successive digits of a binary number, which represents the number of clock pulses corresponding to an immediately preceding pulse interval of a pulse sequence having pulse intervals varied every moment, are shifted down by m digits. Thereafter, the coincidence between those shifted down successive digits and successive digits of a binary number which represents the number of clock pulses corresponding to a required fixed rate delay time is detected through plural exclusive OR gates, so as to find an instant to which the pulse sequence should be dalayed. As a result, the fixed rate delaying of the pulse sequence can be effected at the rate 1/2.sup.m of the immediately preceding pulse interval.