Video tape recorder carrying out field extraction recording and/or reproduction of a video signal

• US 5,619,385 A
• Filed: 06/28/1996
• Issued: 04/08/1997
• Est. Priority Date: 09/17/1992
• Status: Expired due to Fees

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Hamaguchi, Toshihide, Maida, Yoshiaki, Kawakami, Kouichi, Kuge, Satoru
• Primary Examiner(s): Kim, W. C.
• Application Number:
  US08/672,560
• Time in Patent Office: 284 Days
• Field of Search: 360/10.1, 360/64, 360/5, 360/14.2, 360/73.04, 360/73.12
• US Class Current: 360/64
• CPC Class Codes: G11B 15/1875 adaptations for special effects or editing signal processing or indexing therefor G11B27/00
• CPC Class Codes: G11B 15/4672 with provision for information tracking
• CPC Class Codes: G11B 15/4673 by controlling the speed of the tape while the head is rotating
• CPC Class Codes: H04N 5/783 Adaptations for reproducing at a rate different from the recording rate
• CPC Class Codes: H04N 5/915 for field- or frame-skip recording or reproducing

Abstract

A time lapse VTR carrying out field extraction recording includes a gate for extracting intermittently a supplied video signal at a ratio of one field to every three fields, a switching circuit for designating selectively a tape running speed of either 1/9 or 1/12 the tape running speed of a SP mode in the VHS system, and a servo control circuit for driving a capstan motor to run a magnetic tape at the designated tape running speed. The video signal extracted intermittently by the gate circuit is recorded at an azimuth angle differing from each field by a plurality of video heads on a magnetic head running at the designated tape running speed. As a result, the reproduction compatibility of a magnetic tape having field extraction recorded by a time lapse VTR with an EP mode of a conventional VTR of the VHS system is ensured.

Claims

1. A video tape recorder, comprising:

an input terminal for a video signal to be recorded;

means for extracting said video signal at a ratio of one field to every predetermined number of fields to record the extracted video signal alternately by each field on a magnetic tape at first and second azimuth angles differing from each other for forming a pattern of continuous recording tracks;

means for recording a control signal on a control track on said magnetic tape in synchronization with recording by a determined one of said first and second azimuth angles;

a 4-head cylinder of double-azimuth used at least for reproducing said video signal recorded on said magnetic tape, said cylinder including a first pair of heads of a first head having said first azimuth angle and a second head having said second azimuth angle and disposed in the proximity of said first head, and a second pair of heads of a third head having said second azimuth angle and disposed opposing to said first head along the circumference of said cylinder and a fourth head having said first azimuth angle and disposed in the proximity of said third head and opposing to said second head along the circumference of said cylinder;

first switching means for alternately selecting outputs of said first pair of heads and outputs of said second pair of heads for every 1/2 rotation of said cylinder at the time of reproduction of said magnetic tape;

second switching means for selectively switching between a first state in which the reproduced output of said first head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said third head is selected out of said second pair of heads selected by said first switching means, and a second state in which the reproduced output of said second head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said fourth head is selected out of said second pair of heads selected by said first switching means;

means for detecting said control signal recorded on a control track on said magnetic tape at the time of reproduction of said magnetic tape;

control means responsive to said detected control signal for controlling said second switching means to switch to said first state over a preset first time period and to said second state over a second time period differing from said first time period, with the recording track having a predetermined position relationship with the detected control signal on said magnetic tape; and

means for detecting the rotation phase of said cylinder for generating switching pulses to control the switching operation of said first switching means,

wherein there is a predetermined phase difference between a predetermined edge of said detected control signal and a predetermined edge of said switching pulses,

wherein said control means controls said second switching means to switch between said first state and said second state upon the detection of an edge of said switching pulses in relation to a predetermined edge of said detected control signal, and

wherein said control means comprises means for multiplying by two said switching pulses, and counter means to be reset in response to a predetermined edge of said detected control signal for counting a predetermined number of edges of said two-multiplied switching pulses.

2. A video tape recorder having function to reproduce a video signal from a magnetic tape in which a video signal has been recorded alternately by each field at first and second azimuth angles differing from each other at a ratio of one field to every predetermined number of fields to form a pattern of continuous recording tracks, and in which a control signal has been recorded on a control track in synchronization with recording by a predetermined one of said first and second azimuth angles, comprising:

a 4-head cylinder of double-azimuth used for reproducing said video signal recorded on said magnetic tape, said cylinder including a first pair of heads of a first head having said first azimuth angle and a second head having said second azimuth angle and disposed in the proximity of said first head, and a second pair of heads of a third head having said second azimuth angle and disposed opposing to said first head along the circumference of said cylinder and a fourth head having said first azimuth angle and disposed in the proximity of said third head and opposing to said second head along the circumference of said cylinder;

first switching means for alternately selecting outputs of said first pair of heads and outputs of said second pair of heads for every 1/2 rotation of said cylinder at the time of reproduction of said magnetic tape;

second switching means for selectively switching between a first state in which the reproduced output of said first head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said third head is selected out of said second pair of heads selected by said first switching means, and a second state in which the reproduced output of said second head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said fourth head is selected out of said second pair of heads selected by said first switching means;

means for detecting said control signal recorded on a control track on said magnetic tape at the time of reproduction of said magnetic tape;

control means responsive to said detected control signal for controlling said second switching means to switch to said first state over a preset first time period and to said second state over a second time period differing from said first time period, with the recording track having a predetermined position relationship with a detected control signal on said magnetic tape; and

means for detecting the rotation phase of said cylinder for generating switching pulses to control the switching operation of said first switching means,

wherein there is a predetermined phase difference between a predetermined edge of said detected control signal and a predetermined edge of said switching pulses,

wherein said control means controls said second switching means to switch between said first state and said second state upon the detection of an edge of said switching pulses in relation to a predetermined edge of said detected control signal, and

wherein said control means comprises means for multiplying by two said switching pulses, and counter means to be reset in response to a predetermined edge of said detected control signal for counting a predetermined number of edges of said two-multiplied switching pulses.

3. A video tape recorder, comprising:

an input terminal for a video signal to be recorded;

means for extracting said video signal at a ratio of one field to every predetermined number of fields to record the extracted video signal alternately by each field on a magnetic tape at first and second azimuth angles differing from each other for forming a pattern of continuous recording tracks;

means for recording a control signal on a control track on said magnetic tape in synchronization with recording by a determined one of said first and second azimuth angles;

a 4-head cylinder of double-azimuth used at least for reproducing said video signal recorded on said magnetic tape, said cylinder including a first pair of heads of a first head having said first azimuth angle and a second head having said second azimuth angle and disposed in the proximity of said first head, and a second pair of heads of a third head having said second azimuth angle and disposed opposing to said first head along the circumference of said cylinder and a fourth head having said first azimuth angle and disposed in the proximity of said third head and opposing to said second head along the circumference of said cylinder;

first switching means for alternately selecting outputs of said first pair of heads and outputs of said second pair of heads for every 1/2 rotation of said cylinder at the time of reproduction of said magnetic tape;

second switching means for selectively switching between a first state in which the reproduced output of said first head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said third head is selected out of said second pair of heads selected by said first switching means, and a second state in which the reproduced output of said second head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said fourth head is selected out of said second pair of heads selected by said first switching means;

means for detecting said control signal recorded on a control track on said magnetic tape at the time of reproduction of said magnetic tape;

control means responsive to said detected control signal for controlling said second switching means to switch to said first state over a preset first time period and to said second state over a second time period differing from said first time period, with the recording track having a predetermined position relationship with the detected control signal on said magnetic tape; and

means for detecting the rotation phase of said cylinder for generating switching pulses to control the switching operation of said first switching means; and

tracking adjustment means for adjusting the running phase of a magnetic tape at the time of reproduction,

wherein said control means controls said second switching means to switch between said first state and said second state upon the detection of all edge of said switching pulses in relation to the edge that will not have the phase relationship with respect to said detected control signal inverted by phase adjustment of said tracking adjustment means,

wherein said control means comprises means for generating a reset pulse corresponding to an edge, out of the predetermined edges of said switching pulses, included within a range of one period of said switching pulse from a predetermined edge of said detected control signal, means for multiplying by two said switching pulses, and counter means to be reset by said reset pulse for counting a predetermined number of edges of said two-multiplied switching pulses.

4. A video tape recorder, comprising:

an input terminal for a video signal to be recorded;

means for extracting said video signal at a ratio of one field to every predetermined number of fields to record the extracted video signal alternately by each field on a magnetic tape at first and second azimuth angles differing from each other for forming a pattern of continuous recording tracks;

means for recording a control signal on a control track on said magnetic tape in synchronization with recording by a determined one of said first and second azimuth angles;

a 4-head cylinder of double-azimuth used at least for reproducing said video signal recorded on said magnetic tape, said cylinder including a first pair of heads of a first head having said first azimuth angle and a second head having said second azimuth angle and disposed in the proximity of said first head, and a second pair of heads of a third head having said second azimuth angle and disposed opposing to said first head along the circumference of said cylinder and a fourth head having said first azimuth angle and disposed in the proximity of said third head and opposing to said second head along the circumference of said cylinder;

first switching means for alternately selecting outputs of said first pair of heads and outputs of said second pair of heads for every 1/2 rotation of said cylinder at the time of reproduction of said magnetic tape;

second switching means for selectively switching between a first state in which the reproduced output of said first head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said third head is selected out of said second pair of heads selected by said first switching means, and a second state ill which the reproduced output of said second head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said fourth head is selected out of said second pair of heads selected by said first switching means;

means for detecting said control signal recorded on a control track on said magnetic tape at the time of reproduction of said magnetic tape;

control means responsive to said detected control signal for controlling said second switching means to switch to said first state over a preset first time period and to said second state over a second time period differing from said first time period, with the recording track having a predetermined position relationship with the detected control signal on said magnetic tape;

means for delaying an output of said second switching means by a delay time, said delay time corresponding to a time difference for said first and second heads to trace the same position on said magnetic tape when said first head abuts against said magnetic tape at the time of reproduction of said magnetic tape; and

third switching means for selecting an output of said delay means in said first state and selecting an output of said second switching means in said second state to provide the selected output as a reproduced video signal.

5. A video tape recorder having function to reproduce a video signal from a magnetic tape in which a video signal has been recorded alternately by each field at first and second azimuth angles differing from each other at a ratio of one field to every predetermined number of fields to form a pattern of continuous recording tracks, and in which a control signal has been recorded on a control track in synchronization with recording by a predetermined one of said first and second azimuth angles, comprising:

a 4-head cylinder of double-azimuth used for reproducing said video signal recorded on said magnetic tape, said cylinder including a first pair of heads of a first head having said first azimuth angle and a second head having said second azimuth angle and disposed in the proximity of said first head, and a second pair of heads of a third head having said second azimuth angle and disposed opposing to said first head along the circumference of said cylinder and a fourth head having said first azimuth angle and disposed in the proximity of said third head and opposing to said second head along the circumference of said cylinder;

first switching means for alternately selecting outputs of said first pair of heads and outputs of said second pair of heads for every 1/2 rotation of said cylinder at the time of reproduction of said magnetic tape;

second switching means for selectively switching between a first state in which the reproduced output of said first head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said third head is selected out of said second pair of heads selected by said first switching means, and a second state in which the reproduced output of said second head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said fourth head is selected out of said second pair of heads selected by said first switching means;

means for detecting said control signal recorded on a control track on said magnetic tape at the time of reproduction of said magnetic tape;

control means responsive to said detected control signal for controlling said second switching means to switch to said first state over a preset first time period and to said second state over a second time period differing from said first time period, with the recording track having a predetermined position relationship with the detected control signal on said magnetic tape;

means for detecting the rotation phase of said cylinder for generating switching pulses to control the switching operation of said first switching means;

tracking adjustment means for adjusting the running phase of a magnetic tape at the time of reproduction,

wherein said control means controls said second switching means to switch between said first state and said second state upon the detection of an edge of said switching pulses in relation to the edge that will not have the phase relationship with respect to said detected control signal inverted by phase adjustment of said tracking adjustment means,

wherein said control means comprises means for generating a reset pulse corresponding to an edge, out of the predetermined edges of said switching pulses, included within a range of one period of said switching pulse from a predetermined edge of said detected control signal, means for multiplying by two said switching pulses, and counter means to be reset by said reset pulse for counting a predetermined number of edges of said two-multiplied switching pulses.

6. A video tape recorder having function to reproduce a video signal from a magnetic tape in which a video signal has been recorded alternately by each field at first and second azimuth angles differing from each other at a ratio of one field to every predetermined number of fields to form a pattern of continuous recording tracks, and in which a control signal has been recorded on a control track in synchronization with recording by a predetermined one of said first and second azimuth angles, comprising:

a 4-head cylinder of double-azimuth used for reproducing said video signal recorded on said magnetic tape, said cylinder including a first pair of heads of a first head having said first azimuth angle and a second head having said second azimuth angle and disposed in the proximity of said first head, and a second pair of heads of a third head having said second azimuth angle and disposed opposing to said first head along the circumference of said cylinder and a fourth head having said first azimuth angle and disposed in the proximity of said third head and opposing to said second head along the circumference of said cylinder;

first switching means for alternately selecting outputs of said first pair of heads and outputs of said second pair of heads for every 1/2 rotation of said cylinder at the time of reproduction of said magnetic tape;

second switching means for selectively switching between a first state in which the reproduced output of said first head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said third head is selected out of said second pair of heads selected by said first switching means, and a second state in which the reproduced output of said second head is selected out of said first pair of heads selected by said first switching means or the reproduced output of said fourth head is selected out of said second pair of heads selected by said first switching means;

means for detecting said control signal recorded on a control track on said magnetic tape at the time of reproduction of said magnetic tape;

control means responsive to said detected control signal for controlling said second switching means to switch to said first state over a preset first time period and to said second state over a second time period differing from said first time period, with the recording track having a predetermined position relationship with a detected control signal on said magnetic tape;

means for delaying an output of said second switching means by a delay time, said delay time corresponding to a time difference for said first and second heads to trace the same position on said magnetic head when said first head abuts against said magnetic tape at the time of reproduction of said magnetic tape; and

third switching means for selecting an output of said delay means in said first state and selecting an output of said second switching means in said second state to provide the selected output as a reproduced video signal.