JPH03168902A - Tape selector device - Google Patents

Abstract

PURPOSE:To exactly set the recording frequency characteristics at the time of recording while holding a video tape stopped by providing a frequency characteristic setting means which sets the frequency characteristics at the time of recording as the recording frequency characteristics at the time of a recording mode in the reproduction reference signal detected by a detecting means. CONSTITUTION:A detector 14 detects the frequency characteristics of the reproduction reference signal inputted thereto, detects the reproduction signal having the best frequency characteristic and inputs the signal to a controller 16. The frequency characteristic of a recording characteristic varying device 13 is set the same as the frequency characteristic applied to the detected reproduction reference signal. The controller 16 operates a head position controller 15, after this setting, and executes the control to move the position of a recording and reproducing head 111 to the ordinary position having a step with an erasing head 112; thereafter, the controller sets the device to a recording mode and supplies a picture recording signal via a recording characteristic varying device 13 to the recording and reproducing head 111. The reference signal is recorded and reproduced on the video tape erased by moving the recording and reproducing head 111 of a movable type to the position having no step with the erasing head 112 at the time of executing tape selection.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a tape selector device used in a helical scan type video tape recorder (VTR).

(Prior Art) A tape selector device records this reference signal on a tape while changing the frequency characteristics of the reference signal, and then plays back the tape on which the reference signal was recorded, and selects the frequency at which an optimal playback signal is obtained. By setting the characteristics as the recording frequency characteristics of the normal signal during recording, it has the function of maximizing the performance of the tape being used, and has traditionally been used in 3-head audio cassette tape recorders. There is.

FIG. 5 is a diagram illustrating the operation of the tape selector device used in the audio cassette table recorder. First, before recording the original signal, a reference signal is generated from the reference signal generator 1, and the frequency characteristics of the obtained reference signal are changed by the recording characteristic variable device 2, for example, characteristics A, B, etc.
The reference signal is supplied to the recording head 5 while being varied as shown in C, and the reference signal is recorded on the magnetic tape 7. At this time, it is assumed that the magnetic tape 7 is erased by the erasing head 6.

The reproducing head 4 immediately reproduces the reference signal recorded on the magnetic tape 7 by the recording head 5, and outputs the reproduced signal to the detection device 3. The detection device 3 detects the reproduced signal having the best characteristics, and sets the frequency characteristic setting in the recording characteristic variable device 2 at this time to the recording frequency characteristic for the magnetic tape 77.

In this way, in the three-head audio cassette table recorder, since the recording head 5 and the reproducing head 4 are independent, recorded signals can be immediately reproduced. Therefore, since the detecting device 3 can immediately determine whether the reproduced signal characteristics are good or bad when the reference signal is recorded with a certain frequency characteristic, the tape selector device can be monitored relatively easily.

By the way, when the tape selector device described above is applied to a helical scan type VTR, it is impossible to have a recording head and a playback head independently as in the audio cassette tape recorder mentioned above due to cost reasons, so a recording and playback head is used. It is necessary to be wary of the tape selector device mentioned above. In such a case, as shown in FIG. 6, a reference signal with frequency characteristic A is recorded on the videotape 8 from positions 1 to m, and then a reference signal with frequency characteristic B is recorded on the same videotape 8 from positions m to n. Furthermore, a reference signal with frequency characteristic C is recorded on the same videotape 8 from position in to zero. After that, the video tape 8 is rewound to position l, the same video tape 8 is played back, the characteristics of the obtained playback signal are detected, and the frequency characteristics corresponding to the playback signal with the optimum characteristics are determined at the time of recording. This will be set to the recording frequency characteristics.

Here, the distance from position l to m can be shortened to a minimum of one field (one track), but since the tape must be rewound between positions l to n after recording the reference signal, the accurate position l must be determined. This greatly depends on the mechanical accuracy of the traveling system, and the cost to realize this is high, so the time from position 1 to position m must be managed, for example, for 1 second. However, video tape 8 that records a reference signal with one frequency characteristic in this way
If the length of the reference signal is time-managed, if the number of changes in the frequency characteristics of the reference signal increases, the recording and playback time of the reference signal will become longer, and rewinding must also be performed as described above. The drawback was that it took too much time to select the tape to set the frequency characteristics during recording to maximize the characteristics of the tape.

Therefore, as a method of shortening the above-mentioned detection time, it is conceivable to detect the optimum recording frequency characteristic by rotating only the head while the video tape is stopped.

This is because helical scan VTRs record and reproduce signals at a relative speed between the rotating speed of the rotating head and the running speed of the tape, and the running speed of the tape is slower than the rotating speed of the rotating head. The structure depends on the fact that it is possible to record and reproduce signals even when the device is stopped. However, recording and reproducing a reference signal with different frequency characteristics! ! In order to accurately detect a reproduced signal with suitable frequency characteristics, it is necessary to erase the video tape before recording. However, since the current rotary erasing head is placed on a cylinder ahead of the recording/reproducing head, when the video tape is stopped, the trace position E of the erasing head and the recording/reproducing head are A step is created between the trace position H of the head and the trace position H of the head. Therefore, it is necessary to record and reproduce the reference signal at a trace position where erasing is incomplete, and with conventional VTRs, it is difficult to configure a tape selector device that can accurately set recording frequency characteristics during recording. It had the disadvantage of being.

(Problem to be Solved by the Invention) As described above, by recording and reproducing a reference signal whose frequency characteristics are changed while the videotape is stopped, the recording frequency during recording can maximize the characteristics of the videotape. When checking the tape selector device for setting the characteristics, there is a difference in level between the erasing head and the recording/reproducing head mounted on the same cylinder. It is necessary to record and reproduce signals, and there is a drawback that it is not possible to accurately set the recording frequency characteristics during recording to match the characteristics of the videotape.

Therefore, the present invention aims to eliminate the above-mentioned drawbacks by making it possible for a recording/reproducing head to trace the erased portion on a video tape that has been erased by a rotary erasing head, so that the recording frequency characteristic during recording is adapted to the video tape. An object of the present invention is to provide a tape selector device that can accurately set the videotape while the videotape is stopped.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a videotape recorder that erases a videotape using a rotating erasing head and then records signals on the same videotape using a rotating recording/reproducing head, which provides characteristics of the videotape. In the tape selector device for setting recording frequency characteristics of the signal according to Before performing the recording, the position of either or both of the rotating erasing head or the rotating recording/playback head is adjusted so that the rotating recording/playback head traces the erased portion of the stationary videotape erased by the rotating erase head. After erasing the stationary video tape with the rotating erasing head, a moving head position control means generates a reference signal whose frequency characteristics are changed in several steps in one field using the rotating recording/reproducing head. A reference signal recording means for recording on the erased portion of the tape, and a reproduced reference signal obtained by reproducing the reference signal recorded by the reference signal recording means by the rotary recording/reproducing head, which has an optimal frequency characteristic. and a frequency characteristic setting means that sets the recording frequency characteristic of the reproduction reference signal detected by the detection means as the recording frequency characteristic in the recording mode.

(Function) In the tape selector device of the present invention, the head position control means causes the rotary recording/reproducing head to trace the erased portion of the static video tape erased by the rotary erase head before performing the tape selector operation. Then, the position of either or both of the rotary erasing head or the rotary recording/reproducing head is moved. The reference signal recording means erases the stationary video tape with the rotating erasing head, and then erases the reference signal, whose frequency characteristics are changed in several steps in one field, on the video tape using the rotating recording/reproducing head. Record in the erased area. The detecting means detects a reproduced reference signal having an ia frequency characteristic from among reproduced reference signals obtained by reproducing the reference signal recorded by the reference signal recording means using the rotary recording/reproducing head. The frequency characteristic setting means sets the recording frequency characteristic of the reproduction reference signal detected by the detection means as the recording frequency characteristic in the recording mode.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of the tape selector device of the present invention. ■1 is a rotating cylinder equipped with a recording/reproducing head 111 and an erasing head 112; 12 is a reference signal generator that generates a reference signal for detecting the characteristics of a videotape; 13 is the frequency of the reference signal or recording signal; A recording characteristic variable device 14 capable of changing the characteristics over several stages detects the frequency characteristics of the reproduction reference signal reproduced by the recording and reproduction head 111, and detects the optimum one among them. Detection device, l5 is erasing head 11
2, a head position control device for controlling the position of the recording and reproducing head 111; 111 is a control device for controlling each of the above devices to control the tape selector operation or the recording and reproducing operation of the VTR; This is a recording/reproducing head that records and reproduces signals on a video tape (not shown), and is a movable head whose mounting position on the cylinder 11 can be changed. Reference numeral 112 denotes an erasing head for erasing recorded signals on the video tape.

Here, the head position control device 15 serves as a head position control means, the reference signal generation device 12 and the recording characteristic variable device 13 serve as a reference signal recording means, the detection device 14 serves as a detection means, and the control device 6 and the recording characteristic variable device Reference numeral 13 constitutes frequency characteristic setting means.

Next, the operation of this embodiment will be explained. Normally, in the head position control device 15, the erasing head 1↓2 is the recording/reproducing head 1.
The position of the recording/reproducing head 111 is moved and fixed according to instructions from the control device 16 so that it is in a position that precedes the head 11 on the trace.

In such a state, as shown in FIG.
The erasing range on the video tape No. 12 becomes the range shown by E, and the tracing range of the recording/reproducing head 111 becomes the range shown by H, so that both ranges E. H has no overlapping parts and is located at a distance.

Next, before recording a signal, the head position control device 15 moves the recording/reproducing head 111 to a position where there is no step on the trace with respect to the erasing head 112 according to an instruction from the control device l6. . After that, the control device 1
6, the cylinder l1 rotates at a constant speed, and the reference signal generator 12 generates a reference signal. At this time, the video tape is controlled to remain stopped. The reference signal generated from the reference signal generator 12 is input to the recording characteristic variable device l3 and is given a certain frequency characteristic, but at this time, the frequency characteristic is alternated in several steps in predetermined intervals over one field. The control device 16
carried out by. The reference signal output from the recording characteristic variable device 13 is supplied to the recording/reproducing head 111 mounted on the cylinder l1, and the frequency characteristic is varied in several steps within the range indicated by H in FIG. One track is recorded on the videotape. In this way, as soon as the recording of the reference signal for one track is completed, the control device 16 puts the VTR into the reproduction state, and the recording/reproduction head 11
1, the track on which the reference signal is recorded is reproduced. The reproduction reference signal thus obtained is input to the detection device 14. At this time, as shown in FIG.
A recording track of the reference signal is formed in the portion E erased in step 12.

The detection device 14 detects the frequency characteristics of the input reproduction reference signal, detects a reproduction signal with the best frequency characteristics, and notifies the control device 16 of this. Upon receiving this, the control device 16 sets the frequency characteristic of the recording characteristic variable device 13 to be the same as that given to the detected reproduction reference signal. After this setting, the control device W16 operates the head position control device 5 to perform control to move the position of the recording/reproducing head 1↓1 to a normal position with a step relative to the erasing head 112. After that, the device is set to recording mode, and the recording signal is sent to the recording/reproducing head 111 via the recording characteristic variable device 13.
supply to.

According to this embodiment, when performing tape selection, by moving the movable recording/reproducing head 111 to a position with no step relative to the erasing head 112, the erasing head
Since the reference signal can be recorded and reproduced by the recording/reproducing head 111 in the erased portion of the videotape erased by step 12, it is possible to accurately set recording frequency characteristics that match the characteristics of the videotape. .

FIG. 4 is a diagram illustrating another embodiment of the present invention. This example has a structure in which the movable head is an erasing head and the recording/reproducing head is fixed. Therefore, under normal conditions, the part marked E in the figure is the erased part of the erasing head, and the part marked H is the traced part of the recording/reproducing head. On the other hand, W indicates the movable range of the erasing head, and when selecting a tape, the erasing head is moved so that its trace part overlaps the trace part of the recording/reproducing head, and a reference signal is applied to the stationary video tape. Recording and reproduction can be performed in the same manner as in the previous embodiment, and optimal recording frequency characteristics can be set. Therefore, this embodiment also has the same effects as the previous embodiment.

〔Effect of the invention〕

As described above, according to the tape selector device of the present invention, the recording/reproducing head can trace the erased portion on the videotape erased by the rotary erasing head, and the recording frequency at the time of recording compatible with the videotape can be adjusted. Characteristics can be set accurately while the videotape is stopped.

[Brief explanation of the drawing]

Fig. 2 is a block diagram showing an embodiment of the tape selector device of the present invention, Fig. 2 is a diagram showing an example of a trace pattern of the recording/reproducing head and erasing head shown in Fig. 1 in a normal state; Figure 3 is a diagram showing an example of the trace pattern of the recording/reproducing head and erasing head shown in Figures } in the tape select state, and Figure 4 is a diagram showing an example of the trace pattern of the recording/reproducing head of another embodiment of the present invention with respect to the trace position. Figure 5 is a block diagram showing an example of a tape selector device used in a conventional three-head audio tape recorder; Figure 6 is a diagram showing the range of movement of the erasing head. FIG. 7 is a diagram showing a recording portion when recording a reference signal with changed characteristics, and FIG. 7 is a diagram showing an example of a trace pattern of each head showing a step difference between a rotary erasing head and a recording/reproducing head. 11... Cylinder l2... Reference signal generator 13... Recording characteristic variable device 14... Detection device↓5... Head position control device 16... Control device

Claims (1)

[Claims] In a videotape recorder that erases a videotape using a rotating erasing head, and then records a signal on the same videotape using a rotating recording/reproducing head, the recording frequency characteristics of the signal are set in accordance with the characteristics of the videotape. In the tape selector device, either one or both of the rotary erasing head and the rotary recording/reproducing head is of a movable type that can move its mounting position on the cylinder, and before performing the tape selector operation, the static image erased by the rotary erasing head is head position control means for moving the position of either or both of the rotary erasing head or the rotary recording and reproducing head so that the rotary recording and reproducing head traces the erased portion of the videotape in the stationary state; After erasing the video tape with the rotary erasing head, a reference signal recording means records a reference signal whose frequency characteristics are changed over several steps in one field on the erased portion of the video tape using the rotary recording/reproducing head. a detecting means for detecting a reproduced reference signal having an optimum frequency characteristic from among reproduced reference signals obtained by reproducing the reference signal recorded by the reference signal recording means by the rotary recording/reproducing head; 1. A tape selector device comprising: frequency characteristic setting means for setting a frequency characteristic during recording of a detected reproduction reference signal as the recording frequency characteristic in a recording mode.