JP2994971B2 - Intermittent magnetic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermittent magnetic recording apparatus for intermittent recording, which is used for a camera for monitoring and for photographing a slowly moving object with time compression.

[0002]

2. Description of the Related Art Conventionally, the following have been proposed in such an intermittent magnetic recording apparatus. The tape is driven intermittently by driving the capstan motor intermittently, and a video signal for one field is recorded during the running period, and a control signal is simultaneously recorded during the running period. In this case, when recording the control signal, a voltage is applied to the control head at a time that is delayed from the video head switching signal by a predetermined time to switch the N / S of the magnetic field.

[0003]

However, in the above method, the cycle of the control signal is not constant except in a special system in which the intermittent feeding of the tape can be always performed in a constant state. In this case, the tape running becomes unstable. That is, in the case of recording a signal during tape running in which the moving state of the tape is hardly constant at all times, such as intermittent feeding, it is difficult to record a control signal at a precisely constant cycle by the above-described method. .

According to the present invention, a magnetic recording apparatus is disclosed which enables a constant and stable recording of a control signal even in the above-described intermittent recording in which tape running is unstable.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a capstan motor having a frequency generator for generating a signal having a frequency proportional to the rotational speed of a magnetic tape (t) for controlling the running of the magnetic tape (t).
(i), a motor drive pulse is generated by a predetermined signal input, and a drive pulse having a predetermined width is generated by the capstan motor (i).
And a capstan motor drive pulse generating circuit (c) for running the magnetic tape (t) by applying a braking pulse having a predetermined width to the capstan motor (i) by a predetermined signal input. A braking pulse generating circuit (b) for stopping the motor, a magnetic head (n) for magnetically recording a signal on the magnetic tape (t) or reading a signal recorded on the magnetic tape, and a magnetic head (n) A rotation control circuit (d) for controlling the rotation of the magnetic head (n), a recording and reproduction control circuit (g) for controlling the magnetic head (n) to a recording state or a reproduction state by a predetermined signal, and the capstan motor (i).
An FG counter (e) that counts pulses from a frequency generator provided in the magnetic tape (t) by applying a voltage to the control head (I) according to the value of the FG counter (e)
Recording CTL generating circuit (f) for recording a control signal in the memory
The two frequency generators of the capstan motor (i) are provided with their phases shifted from each other, and the capstan motor (i) is provided with a capstan motor based on the phase difference between the pulses from the two frequency generators (j) and (k). The rotation direction of the motor (i) is also detected at the same time, and the count is added / subtracted according to the rotation direction.

[0006]

The reference signal is recorded on the magnetic tape based on the signal of the frequency generator (j) provided in the capstan motor (i) for driving the magnetic tape. Therefore, in a system where the intermittent feeding operation is somewhat unstable. Also, the recording control pulse can be recorded on the magnetic tape by accurately measuring the amount of tape movement. Therefore, it is not necessary to increase the feeding accuracy of the mechanism itself, and therefore it can be realized without increasing the cost even in a normal consumer VTR or the like.

[0007]

The magnetic recording apparatus of the present invention is basically different from the conventional example in that the tape is intermittently driven by driving the capstan motor intermittently and the video signal for one field is recorded during the running period. Since they are the same and the configuration is almost the same,
A detailed description of the configuration is omitted, and the following description focuses on the functional aspects.

FIG. 1 is a block diagram showing an embodiment of the present invention. (i) is a capstan motor for running the magnetic tape (t), and is a known two frequency generator (j) (k) for generating a pulse having a frequency proportional to its rotation.
(Hereinafter referred to as FG), and one FG (k) is attached so that the phase thereof is delayed by 90 degrees with respect to the other FG (j).

(N) is a rotary magnetic head for recording signals on the magnetic tape (t) or reading signals on the magnetic tape (t).

(O) is a motor for rotatingly driving the rotating magnetic head (n).

(I) shows that N is applied to the magnetic tape by applying a voltage.
The control head records a control signal as a magnetic field or an S magnetic field.

(A) is a start pulse generating circuit which generates a capstan start pulse having a predetermined width in synchronization with the head switching pulse when the intermittent recording mode is set.

(B) is a braking pulse generating circuit for stopping the magnetic tape (t) at a time when the capstan motor (i) is started and then moved a predetermined distance in the intermittent recording mode. FG pulses output from FG (j) provided in the capstan motor (i) are counted, and a capstan braking pulse is generated.

FIG. 3C shows that the capstan motor (i) is driven at a predetermined speed based on the head switching pulse and the FG pulse.
This is a rotation control circuit for rotating in phase.

(D) Drive motor for rotating magnetic head (n)
This is a circuit for performing the rotation control of (o).

(G) shows the rotating magnetic head (n) in a recording state,
Alternatively, it is a circuit for controlling the reading state.

(H) is an OR gate for transmitting the output of each of the starting pulse generating circuit (a), the braking pulse generating circuit (b), and the rotation control circuit (c) to the capstan motor (i) at the time of intermittent driving. .

(S) Outputs an OR gate (h) of a start pulse, a braking pulse, and a rotation control signal during intermittent recording, and outputs a rotation control signal during continuous recording.
This is a switch for transmitting to (i).

(E) is an FG counter newly added according to the present invention.
The pulse of FG (j) attached to the capstan motor (i) is counted. This count value is sent to a recording control signal (hereinafter referred to as CTL) creation circuit (f) described later.

The FG counter (e) also receives a pulse of FG (k) at the same time, detects the rotation direction of the capstan motor (i) at the same time based on the phase difference between the two pulses, and adds / counts the count. Subtraction is being performed. That is, in the forward rotation, the count is added, and in the reverse rotation, the count is subtracted.

(F) When the value of the FG counter (e) reaches a predetermined value N1 in the recording CTL generating circuit, an N-pole pulse (high pulse) is applied to the control head (I).
When the value of the FG counter (e) reaches a predetermined value N2, a control signal is recorded on the magnetic tape (t) by applying an S-pole pulse (low pulse) to the control head (I).

FIG. 2 is a timing chart of the actual operation. FIG. 2A shows a head switching pulse, which switches channels 1 and 2 of the rotary magnetic head based on this signal.

(B) The starting pulse initial generation circuit (a) of FIG.
(C) is a braking pulse generated by the braking generating pulse circuit (b) of FIG.

(D) is an output pulse of the FG (j) attached to the capstan motor (i), and this pulse is counted by the FG counter (e) which is a feature of the present invention. still,
The number attached under (d) is this count value.

(E) is a recording mode signal, which is a signal for actually setting the magnetic head in a recording state.

(F) is an output of the recording CTL generating circuit (f) of FIG. 1 and is a voltage applied to the control head (I).

When the recording operation is started by entering the intermittent recording mode, a starting pulse (b) is generated by the starting pulse generating circuit (a) based on the head switching signal (a).
Activate the capstan motor (i).

When the capstan motor (i) starts rotating, a pulse (d) is output from the FG (j) attached to the motor. This pulse is counted by the FG counter (e), and when it reaches a predetermined value (6 in this example), the recording CTL
A high voltage is output (f) by the creation circuit (f). This is a magnetic tape (t) as an N-pole magnetic field by the control head (I).
Recorded above.

At the same time, the braking pulse generation circuit (b)
The G pulse (d) is counted, and when a predetermined value (11 in the example) is reached, a braking pulse (c) is applied to the capstan motor (i) to stop the capstan motor (i).

In the next intermittent feed, a start-up pulse (b) is created in the start-up pulse generating circuit (a) based on the head switching pulse (a) as before, and the capstan motor (i)
Start

When the capstan motor (i) starts rotating, a pulse (d) is output from the FG (j) provided in the motor. This is counted by the FG counter (e), and when the count value reaches a predetermined value (21 in this example), a low voltage is output by the recording CTL creation circuit (f) (f), and the control head (I) )) To record an S-pole magnetic field on the magnetic tape (t).

At the same time, the FG pulse (d) is counted by the braking pulse generating circuit (b), and when a predetermined value (24 in the example) is reached, the braking pulse (c) is applied to the capstan motor (i). To stop the capstan motor (i).

The value of the FG counter (e) is the value of the recording CTL.
Cleared when a start pulse (b) occurs when the output of the creation circuit (f) is low. Further, the FG counter (e) accurately detects the tape moving direction by FG (j) and FG (k) delayed by 90 degrees from the FG (j) in order to accurately measure the tape moving amount, and adds the count based on the detected direction. / Subtraction.

Recording of a video signal by the magnetic head (n) is as follows.
When the recording mode signal (e) in FIG. 2 becomes high, the recording / reproduction control circuit (g) is set to the recording state, and the signal is recorded on the magnetic tape (t).

According to the method described above, even if there is a slight variation in the intermittent feeding of the magnetic tape, the control pulse can be accurately recorded on the magnetic tape, and the recorded portion is reproduced (normal reproduction, not intermittent reproduction). Even when this occurs, smooth reproduction can be performed without causing tape running fluctuation or the like due to servo control.

It is needless to say that the above-described system can be realized by using any of a general-purpose logic integrated circuit, a dedicated integrated circuit, and a microcomputer. Further, the present invention is not limited to the configuration of the above embodiment, and various modifications are possible within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a block diagram of the device of the present invention.

FIG. 2 is a timing chart in the device of the present invention.

[Explanation of symbols]

 (a) Start pulse generation circuit (b) Brake pulse generation circuit (c) Capstan motor rotation control circuit (d) Magnetic head drive motor rotation control circuit (e) FG counter (f) Record CTL creation circuit (g) Record , Regeneration control circuit (i) capstan motor (j) frequency generator

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 15/467

Claims (1)

(57) [Claims] 1. A capstan motor (i) having a frequency generator for generating a signal having a frequency proportional to the rotational speed of a magnetic tape (t) for controlling running of the magnetic tape (t); And a capstan motor drive pulse generating circuit (c) for running the magnetic tape (t) by applying a drive pulse of a predetermined width to the capstan motor (i). A braking pulse generating circuit (b) for applying a braking pulse of a predetermined width to the stun motor (i) to stop the capstan motor, and a signal is magnetically recorded on the magnetic tape (t) or recorded on the magnetic tape. Magnetic head (n) for reading signals
A rotation control circuit (d) for controlling the rotation of the magnetic head (n); a recording / reproduction control circuit (g) for controlling the magnetic head (n) to a recording state or a reproduction state by a predetermined signal; An FG counter (e) for counting pulses from a frequency generator provided on the stun motor (i), and a control head (I) according to the value of the FG counter (e).
And a recording CTL generating circuit (f) for recording a control signal on a magnetic tape (t) by applying a voltage to the magnetic tape (t). Two frequency generators of the capstan motor (i) are provided out of phase. And both frequency generators (j) (k)
Capstan motor based on phase difference of pulse from
An intermittent magnetic recording / reproducing apparatus characterized in that the rotation direction of (i) is simultaneously detected and the count is added / subtracted according to the rotation direction.