JPH051541B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a magnetic recording/reproducing device (hereinafter abbreviated as VTR), and in particular, the present invention relates to a magnetic recording/reproducing device (hereinafter abbreviated as VTR). This relates to a VTR that has improved splicing, in other words, to prevent the recording seams from being disturbed.

[Prior art]

Fig. 1 is a block diagram of continuous shooting using a cue track of the conventional pilot signal system. In the figure, 7 is a cue head for both recording and playback. After the erase signal from the amplifier 1 is amplified by the first amplifier 4, the signal is saturated and recorded on the cue track 20 (see FIG. 2) on the magnetic tape 8 via the switch 5 and the capacitor 6. 3
is a gate circuit which limits the time during which the number of pulses from the reference signal generator 2 and the erasing signal from the erasing signal generator 1 are recorded on the cue track 20. During reproduction, the pulse signal reproduced from the cue track 20 on the magnetic tape 8 is amplified by the second amplifier 13 via the recording/reproduction switch 5, and the waveform is shaped by the waveform shaping circuit 12 and sent to the control circuit 1.
Enter 1.

Reference numeral 14 denotes a servo circuit, which controls tape running using a pilot signal system using a capstan motor 15 in response to commands from the control circuit 11.

FIG. 3a is a diagram showing the vicinity of the cue head 7, and the signal from the changeover switch 5 is transferred to the capacitor 6.
The data is inputted to the queue head 7 via.

Next, the operation will be explained. Assuming that recording is currently in progress, the magnetic tape 8 is erased by a full-width erasing head (not shown), and then a diagonal video track is formed as shown in FIG. The pilot signal F1 is superimposed on
~F4 are recorded in circulation. When the pause signal 9 is input to the control circuit 11 in this state, the control circuit 11 stops recording the video track currently being recorded, issues a reverse command to the servo circuit 14, and outputs a reverse command to the capsulator. The motor 15 is rotated in the reverse direction to transport the magnetic tape 8 in the reverse direction.

At the same time, the gate circuit 3 first opens the gate of the signal from the reference signal generator 2, and sends a pulse at a predetermined reference frequency to the cue track 20 at the cue head 7 through the first amplifier 4, selector switch 5, and capacitor 6. Record the number of pulses. The recording current amplitude value at this time is assumed to be V1 (see FIG. 3b). When the recording of the predetermined pulses is completed, the gate circuit 3 stops the reverse transport after a certain amount of backward transport while erasing the cue track 20, and then temporarily stops and enters a recording standby state. The erase current amplitude value at this time is
V2 (see Figure 3b). At this time, as shown in FIG. 3a, the signal is input to one terminal of the queue head 7 in an alternating current manner through the capacitor 6, and the other terminal of the queue head 7 is connected to ground. Therefore, the waveform at point A of cue head 7 is as shown in FIG. 3b. The state of the magnetic tape at this time is shown in FIG. 2b. In addition, in the same figure, 2
1 indicates a pulse recorded on the cue track 20.

Next, when the pause is released, the servo circuit 14
rotates the capstan motor 15 in the forward direction,
While transporting the magnetic tape 8 in the forward direction, each circuit is switched to the reproduction state, and the capstan is moved so that the pilot frequencies already recorded on the magnetic tape 8 match the order of the newly recorded pilot frequencies. A motor 15 controls tape running. At this time, the changeover switch 5 is connected to the reproduction side, and the cue head 7 reproduces the pulses recorded on the cue track 20. The reproduced pulses are input to the control circuit 11 via the second amplifier 13 and the waveform shaping circuit 12, and the number of pulses is counted. This state is shown in FIG. 2c.

When the number of pulses thus reproduced becomes the same as the number of pulses recorded during reverse transport, recording of the video signal is restarted in synchronization with the head switch pulse 10. The state on the magnetic tape 8 at this time is the second
Shown in Figure d. In addition, in the same figure, numeral 22 indicates the state of a newly recorded video track.

Since the continuous shooting using the conventional pilot signal cue track is constructed as described above, the erasure signal generator 1 is required. In addition, high-quality tapes with high record retention, such as metal tapes, etc.
For Hc tape, the required signal recording current amplitude value V1
However, it was necessary to increase the erase current amplitude value V2.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional tape, and after recording a predetermined number of pulses on a cue track by a cue head during tape reverse transport in a splicing operation, the cue track is transferred to a direct current source. By overwriting with saturated recording, unnecessary pulses on the cue track can be erased without using an erase signal generator like in conventional devices, and the erasure can be ensured, making it possible to perform more accurate splicing. The purpose is to provide a magnetic recording and reproducing device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 is a block diagram of a VTR according to an embodiment of the present invention.The difference from the conventional device shown in FIG. bias voltage
This means that Vref is being applied.

FIG. 5a shows the vicinity of the cue head 7 according to one embodiment of the invention. The signal from the changeover switch 5 is directly input to one terminal of the cue head 7, and the bias voltage Vref, which is half the signal amplitude, is applied to the other terminal, indicating a state in which DC saturation recording is performed.

FIGS. 5c and 5d show how the changeover switch 5 and the gate circuit 3 change in the reverse transfer section, respectively. In addition, Fig. 5e shows point B,
That is, the state of the voltage applied to the cue head 7 is shown. FIG. 5e shows the current flowing through the cue head 7. FIG. Here, when the changeover switch 5 is on the recording side and the gate circuit 3 is closed,
Since a DC saturation recording current of -IP flows through the queue head 7, the queue track 20 is overwritten, and the signal already recorded on the queue track 20 is erased.

Next, the operation will be explained.

When the pause signal 9 is input to the control circuit 11 during recording, the control circuit 11 stops the recording operation after finishing recording the video track currently being recorded, issues a reverse rotation command to the servo circuit 14, and starts the capstan. The motor 15 is rotated in the reverse direction to transport the magnetic tape 8 in the reverse direction, and the changeover switch 5 is set to the recording side.

At the same time, while the magnetic tape 8 is being transported backwards, the gate of the gate circuit 3 is opened, and the signal from the reference signal generator 2 is passed through the first amplifier 4 and applied to the cue track 20 by the cue head 7 for a predetermined number of pulses. Record saturation. When the recording of this predetermined pulse is completed, the changeover switch 5 is left in the recording side and the gate of the gate circuit 3 is closed, and the signal already recorded on the cue track 20 is erased by overwriting with DC saturated recording. While doing so, continue to reverse transport. This situation is shown in FIGS. 5b to 5f.

Next, when the magnetic tape 8 has been reversely transported by a certain amount, the reverse transport is stopped, the tape is temporarily stopped, and the recording standby state is entered. Then, the changeover switch 5 is connected to the playback side, and the following operation is the same as the conventional continuous shooting operation.

In this embodiment, the capacitor of the cue head is removed, a predetermined bias is applied to the cue head, and the signal already recorded on the cue track is erased by overwriting it with DC saturated recording. Unnecessary signals on the cue track can be erased without requiring a separate erase signal generator. Furthermore, for magnetic tapes with height Hc such as metal tapes, it is necessary to increase the erasing current in AC erasing, but as a result of experiments based on the example shown in Figure 4, in DC erasing it is necessary to increase the erasing current to the same level as the recording signal amplitude. Even when erasing using the level setting, erasing was ensured, and I was able to perform highly accurate splicing shots.

In the above embodiment, the bias applied to the cue head is a voltage half the amplitude of the signal, but if the first and second amplifiers operate with both positive and negative power supplies, the bias may be at ground potential.

〔Effect of the invention〕

As described above, according to the present invention, when the tape is transferred backward during a splicing operation, the cue head records a predetermined number of pulses on the cue track, and then overwrites the cue track with DC saturation recording. Since unnecessary signals are erased, there is no need for the erasure signal generator required in the conventional apparatus, and there is an effect that highly accurate continuous shooting can be performed.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing splicing using a cue track using a conventional pilot signal system, Fig. 2 is a diagram showing recording patterns on a conventional magnetic tape, and Fig. 3a is a diagram showing a cue head section of a conventional device. , FIG. 3b is a diagram for explaining its operation, FIG. 4 is a block diagram showing an example of continuous shooting of a VTR according to an embodiment of the present invention, and FIG. 5a is a diagram showing the cue head section of the device. , and FIGS. 5b to 5f are diagrams for explaining the operation. 2...Reference signal generator, 3...Gate circuit, 7
...Cuhead, 8...Magnetic tape, 11...
control circuit, 14... servo circuit, 15... capstan motor, 20... cue track, 21...
...(Kyuu) Pulse. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A running control means that superimposes a plurality of pilot signals with different frequencies onto a video signal and records them on a video track on a magnetic tape, and controls tape running based on the pilot signals during playback, and When a stop signal is input, the recording is stopped, and while the magnetic tape is moved in the opposite direction, the cue head records at least one or more pulses in saturation on a cue track provided separately from the video track, and continues to record the magnetic tape in a predetermined manner. Reverse transport/pulse recording, erasure/stop means for overwriting the cue track by direct current saturation recording while transporting the time magnetic tape in the reverse direction, and then stopping the tape, and a means for moving the magnetic tape in the forward direction when the temporary stop is released. transporting the magnetic tape, controlling the running of the tape so that the frequency order of the pilot signal recorded on the magnetic tape matches the frequency order of the pilot signal to be newly recorded, and reproducing the pulses recorded on the cue track. A magnetic recording/reproducing apparatus comprising: a recording start means for starting a recording operation when the number of reproduction pulses matches the number of pulses recorded during the reverse transport.