Servo system for video recorder

Claim 2

In a video recorder-reproducer for recording and reproducing composite video signals, said signals including a vertical sync, said recorder-reproducer including rotatable mounting means for mounting a plurality of angularly spaced magnetic heads, drive means for driving said mounting means, a moving magnetic tape having its path of travel in the arcuate path of said magnetic heads and a servo system for controlling the rotation of said mounting means, said servo system comprising: first means when each of said heads is in a predetermined angular position for generating a first signal; second means when each of said heads is in a second predetermined angular position for generating a second signal; means for measuring the time period between the generation of each of said first signals and the generation of each of the succeeding of said second signals; means responsive to a deviation from a predetermined time period between the generation of each of said first signals and the generation of the succeeding of said second signals for generating successive velocity error signals; means responsive to said velocity error signals for controlling the speed of said driving means to reduce said error; switching means for successively operating said heads; and means responsive to the generation of each of said first signals for actuating said switching means.

Claim 3

The invention as defined in claim 1, and means for comparing the time period between the generation of each of said second signals and the occurrence of each succeeding vertical sync; means responsive to a deviation from the predetermined time period between the generation of each of said signals and the occurrence of each succeeding vertical sync for generating successive angular position errors; and means responsive to said angular position errors for further controlling the speed of said driving means to reduce said error.

Claim 4

The invention as defined in claim 2, and means for recording a control signal on said magnetic tape, said means including a control head supplied with pulses generated in response to one predetermined angular position of said mounting means, said recorded control signal controlling said switching means for controlling the sequence of operation of said heads.

Claim 5

In a video recorder-reproducer for recording and reproducing composite video signals, said signals including a vertical sync, said recorder-reproducer including rotatable mounting means for a plurality N (where N is any number) of angularly spaced magnetic heads mounted thereon, drive means for driving said mounting means, a moving magnetic tape having its path of travel in the arcuate path of said magnetic heads, and servo system for controlling the rotation of said mounting means, said servo system comprising: a plurality N of position indicating means on said mounting means, said position indicating means being equi-angularly spaced thereon; a first position sensor fixedly mounted in the path of rotation of said position indicating means, said first position sensor generating a first pulse Each time it is passed by one of said position indicating means on said mounting means; a second position sensor spaced from said first position sensor in the arcuate path of travel of said position indicating means, said second position sensor generating a second pulse each time it is passed by one of said position indicating means on said mounting means; means responsive to the generation of each of said first pulses for generating a first sawtooth voltage ramp; additional means responsive to the generation of each of said first pulses for successively switching each of said magnetic heads into operation; means responsive to the generation of each of said second pulses for generating a second sawtooth voltage ramp; additional means responsive to the generation of each of said second pulses for successively sampling the voltage levels of said first sawtooth ramps; means responsive to the deviation of the sampled level from a predetermined voltage level for controlling the speed of said motor; means responsive to each occurrence of said vertical sync for successively sampling the voltage level of said second sawtooth ramps; and means responsive to the deviation of the levels of said second sawtooth voltage ramps from a predetermined level for controlling the angular position of said driving motor.

Claim 6

In a video recorder-reproducer for recording and reproducing composite video signals, said signals including a vertical sync, said recorder-reproducer including rotatable mounting means for a plurality N (where N is any number) of angularly spaced magnetic heads mounted thereon, drive means for driving said mounting means, a moving magnetic tape having its path of travel in the arcuate path of said magnetic heads, and servo system for controlling the rotation of said mounting means, said servo system comprising: a plurality N of position indicating means on said mounting means, said position indicating means being equi-angularly spaced thereon; a first position sensor fixedly mounted in the path of rotation of said position indicating means, said first position sensor generating a first pulse Each time it is passed by one of said position indicating means on said mounting means; a second position sensor spaced from said first position sensor in the arcuate path of travel of said position indicating means, said second position sensor generating a second pulse each time it is passed by one of said position indicating means on said mounting means; means responsive to the generation of each of said first pulses for generating a first sawtooth voltage ramp; additional means responsive to the generation of each of said first pulses for successively switching each of said magnetic heads into operation; means responsive to the generation of each of said second pulses for generating a second sawtooth voltage ramp; additional means responsive to the generation of each of said second pulses for successively sampling the voltage levels of said first sawtooth ramps; means responsive to the deviation of the sampled level from a predetermined voltage level for controlling the speed of said motor; means responsive to each occurrence of said vertical sync for successively sampling the voltage level of said second sawtooth ramps; and means responsive to the deviation of the levels of said second sawtooth voltage ramps from a predetermined level for controlling the angular position of said driving motor.

Claim 7

The invention as defined in claim 4, and an additional position indicating means on said mounting means; a third position sensor mounted in the arcuate path of travel of said additional position indicating means, said third position sensor generating a third pulse each time said additional position indicating means passes said third position sensor; and means for recording said third pulse on said magnetic tape.

Claim 8

The invention as defined in claim 5, and means during playback for controlling the angular position of said mounting means in response to the playback of said control pulse.

Claim 9

The invention as defined in claim 6 wherein said position indicating means are light sources and wherein said position sensors are light sensitive pick-up devices.

Claim 10

In a video recorder-reproducer for recording and reproducing composite video signals, said signals including a vertical sync, said recorder-reproducer including rotatable mounting means for mounting a plurality of angularly spaced magnetic heads, drive means for driving said mounting means, a moving magnetic tape having its path of travel in the arcuate path of said magnetic heads and a servo system for controlling the rotation of said mounting means, said servo system comprising: first means when each of said heads is in a predetermined angular position for generating a first signal; second means when each of said heads is in a second predetermined angular position for generating a second signal; means for measuring the time period between the generation of each of said first signals and the generation of each of the succeeding of said second signals; means responsive to a deviation from a predetermined time period between the generation of each of said first signals and the generation of the succeeding of said second signals for generating successive velocity error signals; and means responsive to said velocity error signals for controlling the speed of said driving means to reduce said error.

Claim 11

In a video recorder-reproducer for recording and reproducing composite video signals, said signals including a vertical sync, said recorder-reproducer including rotatable mounting means for mounting a plurality of angularly spaced magnetic heads, drive means for driving said mounting means, a moving magnetic tape having its path of travel in the arcuate path of said magnetic heads and a servo system for controlling the rotation of said mounting means, said servo system comprising: first means when each of said heads is in a predetermined angular position for generating a first signal; second means when each of said heads is in a second predetermined angular position for generating a second signal; means for measuring the time period between the generation of each of said first signals and the generation of each of the succeeding of said second signals; means responsive to a deviation from a predetermined time period between the generation of each of said first signals and the generation of the succeeding of said second signals for generating successive velocity error signals; and means responsive to said velocity error signals for controlling the speed of said driving means to reduce said error.

Claim 12

The invention as defined in claim 8, and means for comparing the time period between the generation of each of said second signals and the occurrence of each succeeding vertical sync; means responsive to a deviation from the predetermined time period between the generation of each of said signals and the occurrence of each succeeding vertical sync for generating successive angular position errors; and means responsive to said angular position errors for further controlling the speed of said driving means to reduce said error.

Claim 13

The invention as defined in claim 9, and means for recording a control signal on said magnetic taPe, said means including a control head supplied with pulses generated in response to one predetermined angular position of said mounting means, and switching means for successively operating said heads, said recorded control signal controlling said switching means for controlling the sequence of operation of said heads.