JPS6360958B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for checking the recording function of a magnetic recording/reproducing apparatus (hereinafter abbreviated as VTR), which makes it possible to check the function of the apparatus prior to official recording.

With the spread of VTRs, variable speed playback, program reservations,
As video cameras have become more multi-functional, such as video recording, the operation of VTRs themselves has become more complex. For this reason, when recording TV programs or camera images on a VTR, there have been cases where even beginners and experienced users end up failing to record due to operational errors when in a hurry. On the other hand, even if the operation is correct, there are cases where VTRs that have been used for a long period of time are unable to record properly due to clogging of the video head or deterioration of the circuitry over time.Furthermore, in these cases, it is frustrating to be unable to check anything during recording. It was hot.

In order to deal with the above-mentioned problems, it is possible to install two independent rotating video heads and a playback circuit that play back the same track as the recorded track, and to monitor the recording. , that is most certain. However, this method not only requires two sets of playback systems, making the equipment complex and expensive, but also requires simultaneous playback during recording, which requires a rotary transformer to connect the rotating video head and the electrical circuit that are normally used. Crosstalk interference to reproduced images could not be ignored, making it difficult to put it into practical use.

An object of the present invention is to provide a method for checking the recording function of a magnetic recording/playback device, which eliminates the drawbacks of the above-mentioned prior art, allows reliable checking of the recording mode and performance of the device with a simple configuration, and prevents recording failures. There is a particular thing.

In order to achieve this object, the present invention checks the recording function from the recording pause state of the VTR, records only one field while keeping the magnetic tape stationary, and then transfers that field to two rotating magnetic tapes of the same azimuth. The recording function is checked by playing still images on the video head, and the recording position of the field is controlled so that no interference occurs on the screen when shooting pauses. .

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing the configuration of a rotating video head of a magnetic recording/reproducing apparatus used in one embodiment of the present invention. In the figure, an auxiliary head A'3 having the same azimuth as the A head 1 is provided at a predetermined position near a B head 2 having an azimuth different from that of the A head 1. (Here, the A head 1 and the B head 2 may be separate chips or may be the same chip having an integral structure). 4
is a rotating cylinder on which rotating heads 1, 2, and 3 are mounted.

The general operation of the present invention will be explained based on FIG. 1 and FIG. 2, which is a recording pattern diagram as seen from the magnetic surface recorded on the magnetic tape 5 in the recording pause state. Recording patterns 7, 8, 9, and 10 indicated by dotted lines in FIG. 2 are patterns that have already been recorded.
Assuming that the pattern is written by head 1, the trajectory of the rotating head in the recording pause state is as shown by the solid line.

When a recording function confirmation button (not shown) is pressed in this state, only one field is recorded on the magnetic tape 5 by the A head 1, creating a solid line recording pattern 6. After that, if the same recording pattern 6 is reproduced for a predetermined period of time, the function of confirming the recording function can be realized by viewing the reproduced image. Even if reproduction is performed alternately using the same A head 1 and B head 2 used for recording, the recording pattern 6 having the same azimuth as the A head cannot be reproduced correctly. In the present invention, it is possible to check the recording function by playing back using the A head 1 and the auxiliary A' head 3 of the same azimuth.

Next, the specific operation of the embodiment of the present invention will be explained by the block diagram shown in FIG. 3, the flowchart of the operation shown in FIG. This will be explained using signal waveform diagrams of each part in the figure.

Reference numeral 11 denotes a VTR signal recording and reproducing circuit, and 12 a recording function confirmation control circuit, each of which is composed of an individual logic circuit or a microcomputer. Also, 13 is a rotary transformer, 14 is a recording switch,
15 is a playback switch, 16 is a recording amplifier,
17 is a playback amplifier that receives the A head recording control signal Ar.
The switch 14 is turned on when the A head reproduction control signal Ap is "H" (high level), and the switch 15 is turned on when the A head reproduction control signal Ap is "H".

First, in the recording state (recording pause signal P is "L" (low level)), when the head switching signal SW30 synchronized with the rotating cylinder 4 is "L", the A head recording control signal Ar is set to "H". Normal recording is performed by passing a recording signal current through the head for recording, and when the head switching signal SW30 is "H", the B head recording control signal Br is set to "H" and recording is performed by passing a recording signal current through the B head. (See Figure 6). When the recording pause signal P becomes "H", the recording pause state is entered and the magnetic tape 5 stops, and the recording control signals Ar and Br are set to "L" to stop recording.

Next, it is detected that the recording function confirmation button (not shown) is pressed and the command signal RC becomes "H", and then the A head recording control signal Ar is output for the period when the first head switching signal SW30 is "L". is set to "H" and one field is recorded on A head 1. If the pinch roller is separated in the recording pause state, take measures to press the pinch roller and apply torque to the reel before recording one field to prevent the tape from slackening, or to put the tape into a still image playback state. Immediately after that (in the embodiment, the next "L" period of the head switching signal SW30), the reproduction recording signal RCP is set to "H" for a predetermined time τ or while the recording function confirmation button is pressed, and the head switching signal SW30 is set to "H".
0 is "L", the A head reproduction control signal Ap is "H", and while the head switching signal SW30 is "H", the A' head reproduction control signal A'p is "H", and the A,
A′ Allows you to play still images on both heads and check the recording function. Thereafter, the reproduction control signal RCP becomes "L", and the VTR returns to the recording pause state.

Note that some VTRs have a pause continuous shooting function that aligns the phases of the control signals before and after the recording pause so that there is no image disturbance at the joint.
If the above method is applied directly to such a VTR to check the recording function, interference will occur in the reproduced image near the seam. This situation will be explained using the recording pattern diagram shown in FIG.

When a recording pause command is issued, recording is stopped in the state shown in FIG. 7a. The shaded areas on the magnetic tape 5 are already recorded areas. Next, the magnetic tape 5 is rewound to the position shown in FIG. 7b and stopped, resulting in a recording pause state. Thereafter, when a recording command is issued, the continuous recording function is an operation of running the magnetic tape 5 and starting a new recording from the position (arrow 21) where the previously recorded control signal and the vertical synchronization signal to be newly recorded coincide. Therefore, when checking the recording function in the recording pause state shown in FIG.
As shown in FIG. 3C, since it is not erased by new recording, interference occurs in the reproduced image near the seam.

In the present invention, the above-mentioned interference is solved by performing control as shown in FIG. 8 using the recording function confirmation control circuit 12 shown in FIG. In the recording pause state, the magnetic tape 5 is stopped in the state shown in FIG. 8b. When the recording function confirmation button is pressed, one field is not recorded immediately, but the magnetic tape 5 is run in the normal direction until it reaches the state shown in FIG. 8a, as shown in FIG. 8c, and then Recording of 1 field with A head 1 (shown as recording pattern 20)
Do this. Thereafter, the film is rewound again to the position shown in FIG. 8d and stopped, resulting in a recording pause state. If this is done, the recording pattern 20 for confirming the recording function is erased as shown in FIG. 8e when a new recording is made, so that image disturbance near the seam will not occur.

In the above description, image quality deterioration (mainly unerased colors) occurs due to overwriting immediately after a recorded magnetic tape cassette is mounted on the cassette holder or when the recording function confirmation operation is repeated. In order to solve this problem, in the present invention, as shown in FIG. 9, prior to recording one field to confirm the recording function,
During the period when the head switching signal SW30 is "L", that is, for one field, the one field erasing signal E is outputted as "H" from the recording function confirmation control circuit 12, thereby erasing one field. A high frequency oscillator 31 of about 4 MHz and 20 mA is used as the erasing signal, and erasing is performed by applying it to the A head 1 through the erasing changeover switch 30 for one field. In order to further increase the erasing effect, direct current may be applied instead of high frequency current. In this case, a direct connection means such as a slip ring is required in place of the rotary transformer.

Note that some home VTRs allow the recording speed to be switched (for example, 2-hour and 6-hour modes) for the purpose of long-term recording. In this case, it is desirable to use a head whose width corresponds to the speed in terms of high image quality. Another embodiment will explain how, by using the concept of the present invention, low-speed recording and playback (6-hour mode) is possible using an auxiliary head for checking the recording function. FIG. 10 shows an explanatory diagram of the structure of the rotating video head in that case. In the figure, the head width of the A' head 43 is approximately 30 μm compared to the head width of the A head 1, which is approximately 60 μm, and the head width of the A' head 43 is approximately 30 μm. A B' head 44 of approximately 30 μm is provided.
By using this set of A' head 43 and B' head 44, low speed recording and reproduction is possible. In this example, since the azimuth of the heads is reversed, a means is used to supply a signal obtained by inverting the head switching signal SW30 to each block as a new head switching signal.

As explained above, according to the present invention, the performance of the VTR can be reliably checked with the simple operation of pressing the recording function confirmation button from the recording pause state.
Recording failures can be prevented, and even when continuous pose shooting is performed, there is no interference on the screen due to confirmation of the recording function.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a rotating video head in an embodiment of the present invention, FIG. 2 is a recording pattern diagram on a magnetic tape, FIG. 3 is a block diagram showing an embodiment of the present invention, and FIG. 5 is a circuit diagram showing a head signal switching circuit in an embodiment of the invention, FIG. 6 is a signal waveform diagram of each part in an embodiment of the invention, and FIG. 8th
9 is an explanatory diagram of a one-field erasing means employed in the present invention, and FIG. 10 is an explanatory diagram of a head configuration according to another embodiment of the present invention. Code explanation 1...A head, 2...B head,
3...A' head, 11...signal recording and reproducing circuit,
12... Recording function confirmation control circuit, 14... Recording switch, 15... Playback switching switch, 4
3...A' head, 44...B' head.

Claims (1)

[Scope of Claims] 1. In a magnetic recording and reproducing apparatus employing an azimuth recording method, first and second video heads having different azimuths are mounted on a rotating drum at an interval of approximately 180 degrees, and the second head An auxiliary head having the same azimuth as the first head is installed at a predetermined position near the first head, the recording function confirmation element for confirming the recording function is pressed to run the magnetic recording medium a certain distance, and then the magnetic recording medium is A predetermined length of magnetic recording is performed by the second head while the medium is stopped, and then the recorded information is reproduced as a still image using the second head and the auxiliary head, and then the magnetic recording medium is moved to the predetermined length. A method for checking the recording function of a magnetic recording/playback device, characterized by checking the recording function by reversing the amount.