JP2629350B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape for driving a magnetic tape with a capstan and detecting a relative position of the tape such as a tape counter using a control signal recorded on the magnetic tape. The present invention relates to a recording / reproducing device.

2. Description of the Related Art In a device using a magnetic tape, such as a video tape recorder (hereinafter, referred to as a VTR), a tape counter is provided to know a relative position of the magnetic tape. Especially VTR
In order to find a more accurate position, devices equipped with a so-called linear counter for finding a tape position by counting control signals recorded on a magnetic tape instead of a conventional counter for detecting mechanical rotation are increasing.

Hereinafter, an example of a conventional capstan control circuit will be described with reference to the drawings. FIG. 2 is a block diagram of a conventional capstan control circuit. FIG. 3 (A),
(B), (C) is a diagram showing the positional relationship between the position of the magnetic tape and the control signal when the operation shifts from fast forward playback to rewind playback. FIG. 4A is a diagram showing a change in the speed of the capstan motor when the operation shifts from fast-forward playback to rewind playback.

In FIG. 2, reference numeral 1 denotes a magnetic tape. 2 is a capstan motor. Reference numeral 3 denotes a control head for detecting a control signal (not shown) recorded on the magnetic tape 1. Reference numeral 4 denotes a capstan driving circuit that drives the capstan motor 2. Reference numeral 5 denotes a control circuit for sending a forward rotation command and a reverse rotation command to the capstan drive circuit 4.
Reference numeral 6 denotes a control signal detection circuit that amplifies an output signal from the control head 3 and shapes the signal into a pulse waveform. Reference numeral 7 denotes a counter for counting the number of pulses of the output 61 from the control signal detection circuit 6 in accordance with the forward / reverse rotation command from the control circuit 5.

In FIG. 3, (A) shows a control signal recorded on the magnetic tape 1. (B) shows the movement of the capstan motor 2 when the operation shifts from fast-forward playback to rewind playback. 10 shows the movement of the capstan motor 2 in the conventional example. (C) shows the shaped output 61 from the control signal detection circuit 6 when the capstan motor 2 operates as in the above (10).

In FIG. 4, (A) shows a change in the speed of the capstan motor 2 when the operation shifts from fast-forward playback to rewind playback in the conventional example.

The operation of the conventional capstan control circuit configured as described above will be described below.

When the direction of the capstan motor 2 is changed from the fast forward reproduction to the rewind reproduction, the forward / reverse rotation command is issued while the drive command 51 is output from the control circuit 5 to the capstan drive circuit 4.
52 is changed from the normal rotation command to the reverse rotation command and output.

As shown in FIG. 4A, the capstan motor 2 takes the time T to reduce the forward rotation speed and then starts reverse rotation.
Since the forward / reverse rotation command 52 from the control circuit 5 is also sent to the counter 7 at the same time, the output pulses 61 from the control signal detection circuit 6 are counted and the subtraction is started. However, the time T until the capstan motor 2 actually starts reverse rotation is T
Is not fixed due to the position of the tape, the variation in the torque of the capstan motor 2, and the like.

Also, as shown at 10 in FIG. 3 (B), the capstan motor 2 may turn around near A. At this time, since the relative speed between the magnetic tape 1 and the control head 3 becomes close to the stopped state, the control head 3
Can or cannot reproduce the control signal. This state is shown in FIG. 3 (C). The shaping output 61 from the control signal detecting circuit 6 is output when the magnetic tape 1 stops as shown by the solid line B, and when the magnetic tape 1 rotates in reverse, the pulse shown by the dotted line B is not output. Or may be. That is, when the magnetic tape 1 reciprocates, an error occurs in the numerical value counted by the counter 7.

Further, the same control is performed in the case of rewind reproduction to fast-forward reproduction (not shown), so that the same error as described above occurs.

As described above, in the conventional configuration, when the capstan changes direction near the control signal, an error occurs in the numerical value counted by the counter because the control signal cannot be reproduced. Then, there is a problem that the error is accumulated each time the normal rotation and the reverse rotation are repeated.

Means for Solving the Problems The present invention provides a capstan drive circuit for driving a capstan motor, and the drive circuit for controlling forward and reverse rotation of the capstan motor and performing intermittent drive in the forward or reverse direction. An intermittent drive circuit for controlling the intermittent drive circuit, a control circuit for controlling the intermittent drive circuit so as to perform forward / reverse control of the capstan motor and intermittent drive in the forward or reverse direction, and a control signal recorded on a magnetic tape. A control signal detection circuit for detecting, a counter circuit for counting up and down an output from the control signal detection circuit in accordance with a forward / reverse rotation command of the capstan, and a running speed of the magnetic tape from an output from the control signal detection circuit And a tape speed detection circuit for detecting the tape speed.

According to the above configuration, when the capstan changes from forward rotation to reverse rotation, when the forward rotation command is sent next to the forward rotation intermittent command and then in the reverse rotation command order, and when the direction changes from reverse rotation to forward rotation. By sending a command that attains a predetermined speed after performing an intermittent forward command and a reverse intermittent command according to the respective cases in the order of sending a reverse intermittent command followed by a reverse intermittent command and then a forward rotational command. Accuracy can be improved.

Embodiment Hereinafter, a magnetic recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the magnetic recording / reproducing apparatus of the present embodiment. FIG. 3 (D)
FIG. 6 is a diagram showing a positional relationship between a position of a magnetic tape and a control signal when an operation shifts from fast-forward playback to rewind playback. FIG. 4B is a diagram showing a change in the speed of the capstan motor when the operation shifts from fast-forward playback to rewind playback.

In FIG. 1, reference numeral 1 denotes a magnetic tape. 2 is a capstan motor. Reference numeral 3 denotes a control head for detecting a control signal (not shown) recorded on the magnetic tape 1. Reference numeral 4 denotes a capstan driving circuit that drives the capstan motor 2. Reference numeral 5 denotes a control circuit for sending a forward rotation command and a reverse rotation command to the capstan drive circuit 4. 6
Amplifies the output signal from the control head 3,
This is a control signal detection circuit for shaping into a pulse waveform. Reference numeral 7 denotes a counter which counts the shaped output 61 from the control signal detection circuit 6 in accordance with the forward / reverse rotation command from the control circuit 5. Reference numeral 8 denotes an intermittent drive circuit for controlling the capstan drive circuit 4 so as to stop the capstan 2 after a predetermined time from the control signal. 9 detects the cycle of the output 61 from the control signal detection circuit 6,
This is a tape speed detection circuit for detecting the running speed of the magnetic tape 1.

In FIG. 3, (A) is a magnetic tape 1 as described above.
(B) shows the operation of the capstan motor 2 when the operation shifts from fast-forward playback to rewind playback. Here, 11 shows the movement of the capstan motor 2 in the present embodiment. Third
FIG. 3D shows a shaped output 61 obtained from the control signal detection circuit 6 when the capstan motor 2 operates as shown in the above-mentioned item 11.

FIG. 4B shows how the speed of the capstan motor 2 changes when the operation shifts from fast-forward playback to rewind playback in this embodiment.

The operation of the embodiment of the present invention configured as described above will be described below.

When the direction of the capstan motor 2 is changed from the fast forward reproduction to the rewind reproduction, the forward / reverse rotation command is issued while the drive command 53 is output from the control circuit 5 to the capstan drive circuit 4.
52 is changed from the normal rotation command to the reverse rotation command and output. As shown in FIG. 4 (B), the capstan motor 2 takes the time T2 to reduce the forward rotation speed and then starts reverse rotation. At this time, the cycle of the shaping output 61 is detected by the tape speed detection circuit 9, and when the speed reaches the normal reproduction speed V2, the detection output 91 is output. In the intermittent drive circuit 8, the capstan motor 2 is stopped after a fixed time T3 from the shaping output 61 at the same time when the detection output 91 is input. Since the speed of the magnetic tape 1 is the normal reproduction speed V2, which is a running speed lower than the fast-forward speed V1, the magnetic tape 1 can be stopped at an arbitrary position. Here, in this embodiment, the magnetic tape 1 is stopped at the position A2 which is a position between the control signals.

Next, the capstan motor 2 is reversed to rewind and reproduce the device, and the magnetic tape 1 starts to be driven in the reverse direction. Therefore, the counter 7 starts subtracting the shaped output 61 after a fixed time T3 after the detection output 91 is input.

Also, as shown at 11 in FIG. 3 (B), the direction of the capstan motor 2 is changed from the shaping output 61 in the vicinity of the substantially constant position A2.
Since the control speed (3) can sufficiently reproduce the control signal (not shown) by the control head 3, the shaping output 61 from the control signal detecting circuit 6 as shown in FIG. Is output correctly. For the above reason, no error occurs in the numerical value counted by the counter 7.

In addition, since the same control is performed in the case of rewind reproduction to fast-forward reproduction (not shown), no error occurs as described above.

As described above, according to the present invention, the capstan drive circuit for driving the capstan motor and the drive circuit for controlling the forward / reverse rotation of the capstan motor and performing the intermittent drive in the forward or reverse direction. An intermittent drive circuit for controlling the intermittent drive circuit, a control circuit for controlling the intermittent drive circuit so as to perform the intermittent drive in the forward or reverse direction, and the control signal recorded on the magnetic tape. A control signal detection circuit for detecting, a counter circuit for counting up and down an output from the control signal detection circuit in accordance with a forward / reverse rotation command of the capstan, and a running speed of the magnetic tape from an output from the control signal detection circuit When the capstan changes from forward rotation to reverse rotation. In the order of the forward rotation command followed by the intermittent forward rotation command and then the reverse rotation command, and when the direction changes from reverse rotation to forward rotation, the reverse rotation command is followed by the intermittent reverse rotation command and then the forward rotation command. According to each case, the accuracy of the linear counter can be improved by sending a command for achieving a predetermined speed after performing the intermittent forward rotation command and the reverse intermittent rotation command.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a magnetic recording / reproducing apparatus according to the present invention, FIG. 2 is a block diagram of a conventional magnetic recording / reproducing apparatus, and FIG. 3 is a case where the operation shifts from fast forward reproduction to rewind reproduction. 4 is a timing chart showing the positional relationship between the position of the magnetic tape and the control signal, and FIG. 4 is a time-speed characteristic diagram showing the speed change of the capstan motor when the operation shifts from fast-forward playback to rewind playback. 1 ... magnetic tape, 2 ... capstan motor, 3 ...
Control head, 4 ... Capstan drive circuit, 5
…… Control circuit, 6 …… Control signal detection circuit, 7…
... Counter, 8 ... Intermittent drive circuit, 9 ... Tape speed detection circuit.

Claims (1)

(57) [Claims] A capstan drive circuit for driving a capstan motor; an intermittent drive circuit for controlling the forward / reverse rotation of the capstan motor and controlling the drive circuit to perform intermittent drive in a forward or reverse direction. A control circuit for controlling the intermittent drive circuit so as to control forward and reverse rotation of the capstan motor and perform intermittent drive in the forward or reverse direction, and a control signal detection circuit for detecting a control signal recorded on a magnetic tape A counter circuit that counts up and down the output from the control signal detection circuit in accordance with the forward / reverse rotation command of the capstan, and a tape speed detection that detects a running speed of the magnetic tape from an output from the control signal detection circuit. Circuit, and when the capstan changes from forward rotation to reverse rotation, forward rotation When the direction changes from reverse rotation to forward rotation after sending the missing command, or when the direction changes from reverse rotation to forward rotation, forward rotation command is sent after reverse rotation intermittent command is sent next to reverse rotation command. A magnetic recording / reproducing apparatus, which sends a command to reach a predetermined speed after performing an intermittent command reverse intermittent command.