Field skip mode video tape recorder
阅读：301发布：2023-01-12
专利汇可以提供Field skip mode video tape recorder专利检索，专利查询，专利分析的服务。并且A field skip mode video tape recorder wherein a magnetic tape is transported while being slantly wound about half the periphery of two rotary magnetic heads which are connected to two sections of a halved slip ring and a brush is adapted to be alternately contacted with said two sections of the slip ring so that during the recording operation, only even fields of a video signal to be recorded may be supplied to one of the two heads, namely a recording head in synchronism with the period during which the recording head is connected with the brush and the tape, and during the reproducing operation, output signals from the heads which alternately appear at the brush are supplied to a single playback amplifier.，下面是Field skip mode video tape recorder专利的具体信息内容。
1. A field skip mode video tape recorder which has a rotary head device including a rotary head holder, a recording-reproducing head and a reproducing head, said heads being mounted on the rotary holder at different levels and spaced apart from each other by about 180*, and means for transporting a magnetic tape slantly around about at least half the periphery of said rotary head device, wherein an improvement comprises: a. head switching contact means adapted to alternately establish external connection with respect to said heads at a point of time that is earlier than the appearance of the vertical synchronizing signal of a video signal to be recorded by a period of time corresponding to from 0.5 to 2.5 percent of one cyclic period of rotation of said rotary head device; b. a reproducing amplifier; c. means for supplying said video signal to be recorded to said switching contact means for a predetermined period of time during the recording operation; and d. means for supplying to said reproducing amplifier the outputs of said heads through said switching contact means during the reproducing operation, wherein the point of time when the supply of said video signal is initiated is so made as to be earlier by a period of time corresponding to about 2 to 0 percent of one cyclic period of rotation of said rotary head device than the point of time when said recording-reproducing head is established the connection with said switching contact means, and the point of time when the signal supply is terminated is so selected to be within a period between the point of times when the connection of said recordingreproducing head with and switching contact means is interrupted and the point of time when a vertical synchronizing signal contained in the video signal occurs.
2. A field skip mode video tape recorder according to claim 1, wherein said predetermined period of time is so determined as to correspond to about 50 to 54.3 percent of one cyclic period of rotation of the rotary head device.
3. A field skip mode video tape recorder according to claim 2, wherein said predetermined period of time is so determined as to correspond to about 52 percent of one cyclic period of rotation of said rotary head device.
4. A field skip mode video tape recorder which has a rotary head device including a rotary head holder with a rotary shaft a recording-reproducing head and a reproducing head, said heads being mountEd on the rotary holder at different levels and spaced apart from each other by about 180*, and means for transporting a magnetic tape slantly around about at least half the periphery of the rotary head device, wherein an improvement comprises: a. two ring-like conductive regions provided on said rotary holder coaxially with respect to the rotating shaft of said holder, one of said conductive regions being divided into two arcuate segments and insulated from each other with an insulation distance between the opposing ends thereof; b. two brushes adapted for sliding contact with said two ring-like conductive regions respectively; c. a reproducing amplifier; d. means for supplying a video signal to be recorded to said brushes for a predetermined period of time during the recording operation; and e. means for connecting the brushes to said reproducing amplifier during the reproducing operation, wherein each of said two heads has a coil, one end of each coil being connected in common to said ring-like conductive region and the other end of each coil being connected to the arcuate segments, respectively, so that the coils are alternately connected with said brushes at every half rotation of said rotary head device, wherein the point of time when the coils are switched is selected to be earlier by a period of time corresponding to about 0.5 to 2.5 percent of one cyclic period of rotation of said rotary head device than the point of time when a vertical synchronizing signal of the video signal to be recorded occurs, and wherein the point of time when the video signal is supplied to the brushes by said video signal supplying means is selected to be earlier by about 2 to 0 percent of one cyclic period of rotation of said rotary head device than the point of time when said recording-reproducing head is connected with said brushes, and the point of time when the video signal supply is terminated is selected to be within a period between the point of time when the connection of said recording-reproducing head with said brushes is interrupted and the point of time when a vertical synchronizing signal occurs.
5. A field skip mode video tape recorder according to claim 4, wherein said predetermined period of time is so determined as to correspond to about 50 to 54.3 percent of one cyclic period of rotation of said rotary head device.
6. A field skip mode video tape recorder according to claim 4, wherein said predetermined period of time is so determined as to correspond to about 52 percent of one cyclic period of rotation of said rotary head device.
7. A field skip mode video tape recorder according to claim 4, wherein said video signal supplying means (e) includes a. means for extracting from the video signal to be recorded only those ones of the vertical synchronizing signals contained therein which occur subsequent to the points of time when the reproducing head is connected with the brushes; b. a monostable multivibrator which is triggered by the output signals of the extracting means so as to be rendered conductive for a period of time shorter than about 0.5 to 4.3 percent of one cyclic period of rotation of said rotary head device; and c. a gate circuit which is rendered conductive only during the conducting period of said monostable multi-vibrator.
8. A field skip mode video tape recorder according to claim 4, wherein said video signal supplying means (e) includes: a magnet piece fixed to said rotary holder, and a detector head for detecting the access of the magnet piece said magnet piece being adapted to provide a detection pulse into the detector head at every point of time that is later by about 0.5 to 2.5 percent of one cyclic period of rotation of said rotary head device than the point of time when said reproducing head is connected with the brushes.
9. A field skip mode video tape recorder for recording and reproducing a video signal including vertical synchronizing pulses, said tape recorder having a rotary head device which includes a recording-reproducing head and a reproducing head and a rotary head holder operatively rotated in synchronism with the vertical synchronizing pulses for mounting thereon said heads at different levels with substantially 180* in angular difference therebetween with respect to an axis of said rotary head holder, and means for transporting a magnetic tape slantly around about at least half of the periphery of said rotary head device, wherein the improvement comprises: head switching contact means having an input-output terminal for operatively connecting said input-output terminal thereof to said heads alternately at a moment that is earlier by 0.5 to 2.5 percent of one cyclic period of rotation of said rotary head holder than a moment when the vertical synchronizing pulses of the video signal occurs; a gate circuit having input and output terminals, said input terminal being supplied with the video signal to be recorded, and said gate circuit selectively transmitting the video signal supplied to the input terminal to the output terminal thereof for a limited period of time whose commencement is set to be on or slightly before every commencement of the connection between said recording-reproducing head and said input-output terminal of said head switching contact means and whose end is set to be slightly after every termination of the connection between the recording-reproducing head and the input-output terminal; a signal reproducing amplifier having input and output terminals for amplifying a signal supplied to the input terminal thereof; and a function selector switch for selectively connecting the input-output terminal of said head switching contact means to the output terminal of said gate circuit when said tape recorder is in a recording operation and to the input terminal of said signal reproducing amplifier when said tape recorder is in a reproducing operation; whereby said gate circuit supplies the video signal to be recorded to the input-output terminal of said head switching contact means for a period of time not shorter than 50 percent of one cyclic period of rotation of said rotary head holder when said tape recorder is in the recording operation whereas a video signal reproduced by each of said heads is time sequentially supplied alternately to the input terminal of said signal reproducing amplifier for a period of time which is 50 percent of one cyclic period of the rotation of said rotary head holder when said tape recorder is in the reproducing operation.
10. The improvement in a field skip mode video tape recorder according to claim 9, wherein the moment when the transmission of the video signal from the input terminal to the output terminal of said gate circuit is initiated is so set as to be about 2 to 0 percent of one cyclic period of rotation of said rotary head holder as early as a moment when the connection between said recording-reproducing head and the input-output terminal of said head switching contact means commences, and the moment when said video signal transmission is terminated is so set as to be within a period between a moment when the connection between said recording-reproducing head and the input-output terminal is released and a moment when a vertical synchronizing pulse occurs subsequently after the release of the connection between said recording-reproducing head and the input-output terminal.
11. The improvement in a field skip mode video tape recorder according to claim 9, which further comprises: means for generating control pulses representative of only those ones of the vertical synchronizing pulses which occur subsequent to the moment when said reproducing head is connected with the input-output terminal of said head switching contact means; and a monostable multivibrator which is triggered by said control pulses so as to be rendered conductive for a period of time shorter than about 0.5 to 4.3 percent of one cyclic period of rotation of said rotary head holder; said gate circuit being rendered conductive only during the conductive period of said monostable multivibrator.
12. The improvement in a field skip mode video tape recorder according to claim 9, which further comprises: a magnet piece fixed to said rotary holder; and a detector disposed to be magnetically coupled with said magnetic piece intermittently during rotation of said rotary head holder for detecting the access of said magnet piece thereto and for generating a detection pulse in response to detection of the access, said magnet piece and said detector being so disposed that the generation of the detection pulse is later by about 0.5 to 2.5 percent of one cyclic period of rotation of said rotary head holder than the connection between said reproducing head and the input-output terminal of said head switching contact means has been completed.
13. The improvement in a field skip mode video tape recorder according to claim 9, wherein said gate circuit operatively transmits the video signal to be recorded from the input to the output terminals thereof for a period of time of about 50 to 54.3 percent of one cyclic period of rotation of said rotary head holder.
14. The improvement in a field skip mode video tape recorder according to claim 13, wherein said gate circuit operatively transmits the video signal to be recorded from the input to the output terminals thereof for a period of time of about 52 percent of one cyclic period of rotation of said rotary head holder.
15. The improvement in a field skip mode video tape recorder according to claim 9, wherein said head switching contact means comprises: two-ring shaped conductive regions provided coaxially with respect to each other and rotated in synchronism with said rotary head holder, one of said conductive regions being divided into two arcuate segments and insulated from each other with an insulation distance between each pair of opposing ends thereof; and two brushes adapted to slidably contact with said two ring-shaped conductive regions, respectively; said input-output terminal being provided on said brushes said recording-reproducing head being connected between one of the two arcuate segments of said one conductive region and the other one of said conductive regions, and said reproducing head being connected between the other one of the two arcuate segments and said the other one of the conductive regions.
16. The improvement in a field skip mode video tape recorder according to claim 15, which further comprises: means for generating control pulses representative of only those ones of the vertical synchronizing pulses which occur subsequent to the moment when said reproducing head is connected with the input-output terminal of said head switching contact means; and a monostable multivibrator which is triggered by said control pulses so as to be rendered conductive for a period of time shorter than about 0.5 to 4.3 percent of one cyclic period of rotation of said rotary head holder; said gate circuit being rendered conductive only during the conductive period of said monostable multivibrator.
17. The improvement in a field skip mode video tape recorder according to claim 16, which further comprises: a magnet piece fixed to said rotary head holder; and a detector disposed to be magnetically coupled with said magnetic piece intermittently during rotation of said rotary head holder for detecting the access of said magnet piece thereto and for generating a detection pulse in response to detection of the access, said magnet piece and said detector being so disposed that the generation of the detection pulse is later by about 0.5 to 2.5 percent of one cyclic period of rotation of said rotary head holder than the connection between said reproducing head and the input-Output terminal of said head switching contact means has been completed.
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