JPH0516666Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention relates to a rotating head type magnetic tape reproducing device such as a VTR, and in particular, it is a method for feeding a magnetic tape using control signals reproduced by a rotating head. The present invention relates to a rotary head type magnetic tape reproducing device equipped with an automatic tracking device suitable for automatic tracking.

(b) Prior Art In the conventional tracking method using a control track used in VRT, the polarity of the tracking error signal does not change with respect to the feeding direction of the magnetic tape.

That is, the timing of the tracking reference pulse A1 and the reproduction control signals B1 and C1 when the magnetic tape is run in the forward direction is as shown in the characteristic diagram of FIG. In this case, the reproduction control signal C1 indicates a time when the magnetic tape is advanced in phase with respect to the reproduction control signal B1.

On the other hand, when the magnetic tape is run in the opposite direction, the timings of the tracking reference pulse A2 and the reproduction control signals B2 and C2 are as shown in the characteristic diagram of FIG. In this case, if the magnetic tape is being fed in the forward direction with respect to the reproduction control signal B2, the timing will still be as in the reproduction control signal C2. Therefore, the polarity of the tracking error signal does not change.

However, in a method in which a tracking error signal is obtained from a pattern recorded on a helical by a rotating head, the polarity of the tracking error signal is inverted depending on the feed direction of the magnetic tape, as shown in the characteristic diagrams of Figures 4 and 5.

In other words, Figure 4 shows the trajectory of the rotating head when the magnetic tape is fed in the normal direction, and F _f is F _po
This shows the trajectory of the magnetic tape as it progresses relative to the magnetic tape. On the other hand, Figure 5 shows the trajectory of the rotating head when the magnetic tape is fed in the opposite direction to the normal direction, and R _f is the trajectory when the magnetic tape is being fed in relation to R _po . It shows. As described above, by comparing FIGS. 4 and 5, it can be seen that the polarity of the tracking error signal is reversed depending on the feeding direction of the magnetic tape.

(c) Problems to be solved by the invention As mentioned above, when obtaining a tracking error signal from a pattern recorded on a helicopter using a rotating head, it is difficult to obtain a tracking error signal from a control signal depending on the running direction of the magnetic tape. There was a problem in that automatic tracking was not possible during reverse playback because the polarity of the tracking information was different.

The object of this invention is to provide a rotary head type magnetic tape reproducing apparatus which eliminates the above-mentioned problems.

(d) Means for solving the problem The rotary head type magnetic tape reproducing device according to this invention is provided with a switching means for switching the polarity of the tracking information obtained from the reproduced control signal according to the feeding direction of the magnetic tape. By doing so, we are trying to solve the problem.

(e) Effect When the magnetic tape is run in the opposite direction to the normal direction, the polarity of the tracking information obtained from the reproduced control signal is reversed by the switching means, even during reverse reproduction.
Automatic tracking is now possible.

(F) Embodiment An embodiment of the rotary head type magnetic tape reproducing apparatus according to this invention will be described with reference to FIG. FIG. 1 is a circuit diagram showing the overall configuration of the switching means.

In the figure, 1 is an input terminal for a tracking error signal obtained by a rotary head reproducing a pattern recorded on a magnetic tape, and 2 is an input terminal for a tracking error signal obtained by a rotating head reproducing a pattern recorded on a magnetic tape.
An input terminal for a control signal that determines the magnetic tape feeding direction output from the CPU; 3 is a non-inverting amplifier consisting of a comparator; 4 is an inverting amplifier consisting of a comparator; 5;
6 is an analog switch, 7 is an inverter, and 8 is an output terminal for a tracking error signal corresponding to the feeding direction of the magnetic tape.

By configuring as above, firstly, when the magnetic tape is running in the normal direction,
For example, a positive pulse control signal indicating the running direction of the magnetic tape is inputted from the CPU to the input terminal 2.

This control signal turns the analog switch 5 on and the other analog switch 6 off. When the analog switch 5 is turned on, the tracking error signal applied to the input terminal 1 is supplied to the output terminal 8 through the non-inverting amplifier 3.

On the other hand, when the magnetic tape is running in a direction opposite to the normal direction, a control signal of, for example, a negative pulse is input from the CPU to the input terminal 2, indicating the running direction of the magnetic tape.

This control signal turns off the analog switch 5 and turns on the other analog switch 6. At this time, since the magnetic tape is running in the opposite direction to the normal direction, input terminal 1 has
A tracking error signal with reversed polarity is applied. This tracking error signal whose polarity is inverted is turned into a tracking error signal by the inverting amplifier 4 with the same polarity as when traveling in the normal direction, and the tracking error signal is turned on. The signal is supplied to the output terminal 8 through the analog switch 6.

In this way, according to the above embodiment, tracking error signals of the same polarity can be output without being affected by the running direction of the magnetic tape.

(g) Effects of the invention According to the rotary head magnetic tape playback device of this invention, it is possible to obtain a tracking error signal of the same polarity without being affected by the running direction of the magnetic tape. Automatic tracking can be applied. This provides effects such as being able to fix the noise bar period of the reproduced RF.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of this invention. 2 to 5 are characteristic diagrams showing conventional examples. 1... Tracking error signal input terminal, 2
...Control signal input terminal, 3...Non-inverting amplifier,
4... Inverting amplifier, 5, 6... Analog switch, 7... Inverter, 8... Tracking error signal output terminal.

Claims (1)

[Claims for Utility Model Registration] A magnetic tape is wound around the outer periphery of a cylinder having a rotating head at a predetermined angle, and a capstan is provided to run the magnetic tape at a predetermined constant speed, and a control signal recorded on the magnetic tape is rotated. In a rotary head type magnetic tape reproducing device configured to perform playback by a head and control the rotational phase of a capstan, a switching device that switches the polarity of tracking information obtained from a reproduced control signal according to the feeding direction of the magnetic tape. A rotary head type magnetic tape, characterized in that a means is provided to enable rotational phase control of a capstan using a reproduced control signal even when the magnetic tape is running in a direction opposite to the normal direction. playback device.