Digital formatter, controller, and head assembly for video disk recording system, and method

• US 4,724,495 A
• Filed: 10/04/1985
• Issued: 02/09/1988
• Est. Priority Date: 11/15/1982
• Status: Expired due to Fees

• Current Assignee: David J. Hedberg, Edward P. Denta Jr, Victor E. Jo Chiong
• Original Assignee: David J. Hedberg, Edward P. Denta Jr, Victor E. Jo Chiong
• Inventors: Hedberg, David J., Denta, Edward P. Jr., Jo Chiong, Victor E.
• Primary Examiner(s): Hecker, Stuart N.
• Assistant Examiner(s): Bowler, Alyssa H.
• Application Number:
  US06/784,674
• Time in Patent Office: 858 Days
• Field of Search: 360/22, 360/48, 360/98, 360/40, 360/97, 360/32, 360/62, 360/64, 360/67, 360/68, 360/70
• US Class Current: 360/22
• CPC Class Codes: G11B 19/28 Speed controlling, regulating, or indicating G11B19/24 takes precedence
• CPC Class Codes: G11B 2220/20 Disc-shaped record carriers
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 5/5521 across disk tracks spiral track following G11B5/596
• CPC Class Codes: H04N 5/781 on disks or drums
• CPC Class Codes: H04N 9/808 involving pulse code modulation of the composite colour video-signal

Abstract

A real-time magnetic digital video disk recording system has been developed for applications in on-line digital imaging systems and off-line fast access image storage and retrieval buffers. The disk recorder uses new high density recording technology and Winchester computer drive technology in a unique peripheral configuration which is fully synchronized to video system timing, provides for flexible formatting, achieves fast random access to a large video image file, and eliminates the need for complex data controllers. The recorder includes two independent actuator and head assemblies for alternately recording successive video fields on separate tracks on separate zones A and B of a disk stack. Movement of one of the actuators and head assemblies is controlled and occurs within a field time to skip tracks containing media flaws to achieve real time digital video recording. The invention bidirectionally receives and transmits data from buses of one size into buses of another size and formats the data into a recordable, compatible format, all under program control. The invention provides unique spindle speed timing acquisition. The invention provides a new circuit for the magnetic read/write head.

Claims

1. A digital formatter for converting a data stream N bits wide into a data stream M bits wide for use in destination circuitry and for reconverting said data stream from M bits wide to N bits wide when received back from destination circuitry, where M and N are integers, comprising

an input bus for transferring a data stream N bits wide,

an output bus for transferring a data stream M bits wide to and from destination circuitry,

a source of clock signals,

a plurality of N serial/parallel/serial shifters having inputs connected across said input bus, each having a serial output of M bits,

a first plurality of N latches, each having M bit width, said latches being connected to the outputs of the serial/parallel/serial shifters respectively and responsive to said clock signals for latching and recycling every M clock signals whereby a data stream M words long each N bits wide at the input bus are converted into N words M bits wide at the output bus for delivery to destination circuitry,

a second plurality of N latches, each having an input M bits wide connected to the output bus and having an output connected to the input bus, said serial/parallel/serial shifters being responsive to said clock signals for shifting data thereon N words, M bits wide, to said input bus as M words, N bits wide for redelivery to the input bus,

means for connecting the output of the serial/parallel/serial shifters to the input bus.

2. The formatter as in claim 1 wherein said shifters and latches are programmable to change the value of N, and means for programming the shifters and latches to a predetermined value of N.

3. A video recording system for recording a video signal including a plurality of video fields and video sync pulses comprising,

a plurality of recording disks having a plurality of data recording surfaces thereon,

means for mounting said disks for coordinate rotating movement at a predetermined speed,

a servo disk mounted to rotate in aligned synchronism with said recording disks, said servo disk including a surface carrying a servo reference signal

a plurality of read/write heads and a servo read head each of which is associated to a respective one of said recording surfaces and to said servo disk surface, respectively,

actuator means for mounting said plurality of heads and including arm means for carrying said heads over each respective surface in predetermined alignment with respect thereto to define a plurality of data tracks and a servo track on which data and servo information is recorded and,

means for synchronizing the video recording so that each video field is recorded on a single cylinder defined collectively by the plurality of the data tracks on the recording surfaces taken together with said servo surface so that said servo signal serves to establish a position synchronizing signal to which said plurality of data tracks are physically synchronized,

motor means for rotating said disks,

means for incrementally adjusting the speed of the motor means including a phase lock loop having a high frequency output pulse triggered by said video sync pulses,

means for comparing said servo reference signal with said phase lock loop signal, and shift means for adding or subtracting at least one output pulse to or from the output of said phase lock loop circuit between said video sync pulses.

4. A video recording method for a video signal including synchronization pulses defining fields, said signal being converted into a parallel digitized data stream, the steps of

providing a plurality of recording disks having a plurality of data recording surfaces thereon,

rotating said disks together in coordinate movement,

providing a servo disk mounted to rotate with said recording disks and having a surface containing tracks of servo reference signal,

providing a first plurality of read/write heads and a servo reading head each associated with one of said recording and servo disk surfaces respectively,

actuating said first plurality of heads over each respective recording surface in a first zone,

providing a second plurality of read/write heads and a servo head each associated with one said recording and servo surfaces, respectively

actuating said second plurality of heads and said servo head in a second zone independently of said actuating step of said first plurality of heads,

synchronizing the video recording so that each video field is recorded on the single cylinder defined collectively by tracks on all recording surfaces of one zone taken together,

establishing a position synchronizing signal from said servo control disk to which all said data tracks are physically synchronized and,

recording alternate video fields through said first and second pluralities of heads on alternative zones.

5. A video disk recording system comprising,

a magnetic disk having a recording surface,

a read/write head associated with said recording surface,

actuator means for mounting said read/write head over said recording surface,

a read/write amplifier including a magnetic head operating circuit mounted on said actuator means and including a write circuit for providing a current source in response to write signals, and a read circuit including a low noise preamplifier,

solid state switching means for selectively connecting said read circuit or said write circuit to said head and for switching rapidly therebetween, said switching means being under control of an electrical signal,

said read circuit, write circuit, solid state switching means being constructed as discrete hybrid circuits, and

means for mounting said hybrid circuits on said actuator means in proximity of its associated read/write head.

6. The system as in claim 5 in which each said read/write head includes means forming a bifilar wound magnetic head, and said switching means includes

a high current write amplifier,

a low noise read preamplifier,

and a diode switching circuit responsive to a first bias condition for connecting said write amplifier to said bifilar head and for being non-conductive to signals at the input of said pre-amplifier, and further responsive to a second bias condition for rendering said write amplifier inoperative while becoming conductive to read signals from said head.