JPH0676417A - Capstan speed controller - Google Patents

Abstract

PURPOSE:To enable recording and reproducing even at an optional different tape speed irrespective of any multiple of integer by equipping capstan motor FG pulse generators in plural systems and changing FG pulses in response to a tape speed. CONSTITUTION:Two capstan FG pulse generators 2 and 3 are fitted to a capstan motor 1, and two kinds of FG pulses (a) and (b) are outputted from the generators 2 and 3. The pulses (a) and (b) are respectively inputted to a switch circuit 4, and are selected by a tape speed changeover signal (c), and a capstan FG pulse (d) is sent to a capstan speed control circuit 5. The capstan speed is controlled by the pulse (d) in the circuit 5. Consequently, the recording and reproducing can be performed even at a different speed that is not a multiple of integer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan speed control device used in a VTR or the like for recording or reproducing a video signal or the like on a magnetic tape.

[0002]

2. Description of the Related Art Generally, consumer VTRs are capable of recording and reproducing at two or more different tape speeds, but most of them are at tape speeds in which there is an integer multiple relationship between the speeds. In order to control the frame period of the video signal, the capstan motor is controlled such that the frame frequency of 30 Hz is used as a reference signal frequency, and a comparison signal of a frequency that is a multiple of 30 Hz is used as the F of the capstan motor.
Create from G pulse. Normally, this type of capstan speed control device has a capstan FG (Freq
uency Generator) If the pulse generator is one system and the tape speed is an integer multiple, the capstan FG pulse frequency is also an integer multiple, and those capstan FG pulse frequencies are multiples of 30 Hz. In this way, the processing in the capstan speed control circuit is performed.

In FIG. 2, reference numeral 1 is a capstan motor, one capstan FG pulse generator 2 is attached to the capstan motor 1, and the capstan FG pulse generator 2 generates the capstan FG pulse generator 2. The FG pulse is sent to the capstan speed control circuit 5, and the capstan speed control circuit 5 controls the capstan motor drive circuit 6 according to the FG pulse to control the speed of the capstan motor 1.

The details of the processing in the capstan speed control circuit will be described with reference to FIG. In FIG. 3, first, the capstan FG pulse e is 1 / N ₁ , 1 / N ₂ , ...
It is input to the n number of frequency dividing circuits 11, 12 and 13 of 1 / N _n . These frequency dividing circuits 11, 12, and 13 correspond to the types of tape speeds used in the VTR. When three types of tape speeds are used, 1 = N ₁ , 1 / N ₂ , 1 at n = 3.
There are three types, / N ₃ . These frequency dividing circuits 11, 12,
The frequency division ratio of 13 is equal to that of each of the frequency dividing circuits 11, 12, 13
Capstan FG input at the tape speed corresponding to
It is set to a value such that the pulse is at 30 Hz at the output.

In this way, the capstan FG pulse after frequency division output from each of the frequency dividing circuits 11, 12, and 13 is switched and selected by the switching signal f at each speed by the switch circuit 14, so that the capstan speed control is always performed. The capstan FG pulse g input to the circuit 15 is set to 30 Hz.

The capstan speed control circuit 15 compares the capstan FG pulse g with a reference signal h having a frame frequency of 30 Hz and outputs an error voltage signal i for control.

[0007]

However, with the above-described conventional configuration, the capstan FG is used when two or more different tape speeds are not in an integral multiple relationship or at each speed.
If the pulse frequency is not a multiple of 30 Hz, capstan speed control cannot be performed.

For example, when signals can be recorded and reproduced using a plurality of systems having different patterns on a tape in one VTR, conditions such as H arrangement, track pitch, and H number of one track in each system can be satisfied. Therefore, the tape speed for satisfying them does not always have an integral multiple relationship between the systems.

In view of the above situation, the present invention generates a capstan FG pulse having a frequency that can be always processed by a capstan speed control circuit for a plurality of different tape speeds required in a VTR or the like, thereby making it possible to generate an arbitrary plurality of tape speeds. It is intended to enable recording and reproduction at different tape speeds.

[0010]

SUMMARY OF THE INVENTION To achieve the above object, a capstan speed control device of the present invention has a capstan selected at each speed for a plurality of different tape speeds required in a VTR or the like. A plurality of capstan motor FG pulse generators are set so that the number of FG pulses of the motor becomes an appropriate value that can be processed by the capstan speed control circuit, and the FG pulses output from them are provided. By providing a switch circuit that switches according to the tape speed, recording and reproduction are possible even for arbitrary plural different tape speeds that are not in the relation of integer multiples.

[0011]

With the above-mentioned structure, the capstan FG pulse generator having a plurality of systems for a plurality of different tape speeds outputs the capstan speed control circuit at each speed at an appropriate frequency that can be processed by the capstan speed control circuit. The stun FG pulse is switched by the switch circuit and sent to the capstan speed control circuit, thereby enabling capstan control at arbitrary plural different tape speeds.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the capstan speed control device of the present invention will be described below with reference to FIG. 1. The same parts as those of the above-mentioned conventional example are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is a block diagram of the essential parts showing the electrical construction of a capstan speed control device according to the present invention, in which the case where two different tape speeds are required is shown.

In FIG. 1, two capstan FG pulse generators 2 and 3 are attached to a capstan motor 1, and two types of FG pulse a, from the two FG pulse generators 2 and 3. b is output. The two types of FG pulses a and b are respectively input to the switch circuit 4, and the tape speed switching signal c causes the switch circuit 4 to switch.
Are switched, and the selected capstan FG pulse d is sent to the capstan speed control circuit 5. The capstan speed control circuit 5 controls the capstan speed by the capstan FG pulse d.

[0015] If there is for example V ₁ tape speed mode 2 and mode 1 of the tape speed becomes it than 10% faster V ₂ consisting, FG pulses of f ₁ comprising frequency from the capstan FG pulse generator 2 in the mode 1 If it is output, if the number of FG pulses generated by the capstan FG pulse generator 3 per revolution is 10% less than that of the capstan FG pulse generator 2, the capstan FG pulse will be generated at the tape speed V _1. FG pulse frequency f ₂ output from the FG pulse frequency f ₁ and the tape speed V ₂ at the capstan FG pulse generator 3 output from the generator 2 becomes the same frequency, capstan speed control circuit 5 is the same, the switch By simply switching the circuit 4, capstan speed control at two different tape speeds is possible.

[0016]

As is apparent from the above description, according to the present invention, the number of capstan motor FG pulses can be processed in the capstan speed control circuit for a plurality of different tape speeds required for a VTR or the like. By providing multiple systems of capstan motor FG pulse generators set to the appropriate number of FG pulse generations and selecting them according to the tape speed, each of them will not be an integer multiple relationship. Record for different tape speeds,
Playback is possible.

[Brief description of drawings]

FIG. 1 is a principal block diagram showing the configuration of an embodiment of a capstan speed control device of the present invention.

FIG. 2 is a principal block diagram showing an embodiment of a conventional capstan speed control device.

FIG. 3 is a block diagram showing details of a main part of FIG.

[Explanation of symbols]

 1 Capstan motor 2, 3 Capstan FG pulse generator 4 Switch circuit 5 Capstan speed control circuit 6 Capstan motor drive circuit a, b Capstan FG pulse c Tape speed switching signal d Capstan FG pulse after selection

Claims (1)

[Claims] 1. In an apparatus for recording or reproducing a video signal or the like on a magnetic tape, for a plurality of different tape speeds required by the apparatus, the capstan motor FG pulse number selected at each speed is the capstan. Equipped with a plurality of capstan motor FG pulse generators set to the appropriate number of FG pulse generations that can be processed by the speed control circuit,
In addition, it is provided with a switch circuit for switching the FG pulse output from them according to the tape speed, so that recording or reproduction is possible even for arbitrary plural different tape speeds which are not in the relation of integer multiples. Characteristic capstan speed control device.