Magnetic recording and reproducing apparatus and method of adjusting the head-switching point therein
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorHisashige Kitamura
Life of this patent
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Abstract
In a magnetic recording and reproducing apparatus with at least two video heads mounted on a rotating drum, a reference video signal is reproduced, using a stored initial value to control the head-switching point, the interval from the head-switching point to the reproduced vertical synchronizing pulse is measured, and a control value that sets the head-switching point a predetermined distance from the vertical synchronizing pulse is calculated. The calculated control value is stored and used when video signals are subsequently recorded. Different control values may be stored for use with different types of video signals, or the control value may be automatically converted according to the signal type.
Claims16
A method of adjusting a head-switching point of a magnetic recording and reproducing apparatus having at least two video heads mounted on a rotating drum, comprising the steps of:
- (a) storing an initial value in a memory device;
- (b) reproducing a reference video signal, using said initial value to control said head-switching point;
- (c) measuring a first interval from said head-switching point to a vertical synchronizing pulse in the reference video signal reproduced using said initial value;
- (d) calculating, from the measured interval, a control value that sets said head-switching point a predetermined distance from said vertical synchronizing pulse;
- and
- (e) storing the calculated control value in said memory device for future use in recording video signals.
A magnetic recording and reproducing apparatus having at least two video heads mounted in a rotating drum, reproducing a reference video signal to adjust a head-switching point of the two video heads, comprising:
- a servo circuit receiving a sensor signal indicating an angular position of said rotating drum, and providing a controllable delay from said sensor signal, thereby generating a head-switching signal that determines said head-switching point;
- a memory device storing an initial value and a control value;
- and
- a control device coupled to said servo circuit and said memory device, reading said initial value from said memory device, setting said initial value in said servo circuit to control said delay, then receiving a vertical synchronizing signal separated from said reference video signal, comparing said vertical synchronizing signal with said head-switching signal, thereby measuring an interval from said head-switching point to said vertical synchronizing signal, calculating, as said control value, a value that, by controlling said delay, sets the interval from said head-switching point to said vertical synchronizing signal to a predetermined value, storing the calculated control value in said memory device, and setting the calculated control value in said servo circuit when video signals are later recorded by the magnetic recording and reproducing apparatus.
Dependencies are inferred from the claim text.