JPS59101984A - Magnetic picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute a high speed reproduction which is free from a skew distortion and scarcely has a noise even in case when an H list is not formed, by specifying an interval of plural special reproducing heads to a reference head. CONSTITUTION:Reference heads 1, 2 for executing regular recording and reproducing, and special reproducing heads 5, 6 and 7 are provided respectively in the circumference of a drum 10. In this case, an interval of the heads 2, 6, an interval of the heads 1, 5, and an interval of the heads 1, 7 are set to 1.5H, respectively. In this state, in case when an H list is formed, the heads whose reproducing output is larger, among the heads 1, 2, or 5, 6, or 6, 7 are selected and used. On the other hand, in case when the H list is not formed, the heads whose reproducing output is larger, between the heads 2, 7 of 1, 6 are selected and used. In this way, even in case when the H list is not formed, a high speed reproduction which is free from a skew distortion and scarcely has a noise can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording/playback device, and more particularly, to a magnetic recording/playback device capable of switching between two tape running speeds, high-speed playback, and horizontal synchronization signals of video signals not being recorded side by side between adjacent tracks. The present invention relates to a magnetic recording and reproducing apparatus equipped with a special reproducing head capable of reproducing video signals recorded on such magnetic tape.

FIG. 1 is a diagram showing the head arrangement of a conventional magnetic recording/reproducing device. First, the playback operation in a conventional magnetic recording and playback device will be explained with reference to FIG. Around the rotating drum 10 are conventional recording and reproducing heads (L and R azimuth heads) 1. each at an angle of 180 degrees.
In addition to the head 2, a slow and steel playback head (R azimuth head) 3.4 having the same azimuth is provided, and these heads realize slow field playback and still playback. However, as recording times have become longer in recent years, in the case of two tape speeds,
Eight to six heads are required, making the structure very complex. Also, when special playback is performed at a tape speed where the horizontal synchronization signals (H) of the video signal are not lined up between adjacent tracks, so-called H alignment is not established, the heads are arranged as shown in Figure 1. In the magnetic recording/reproducing apparatus, there is a problem in that distortion occurs when the head crosses the track, that is, skew distortion occurs in which the upper part of the screen is tilted diagonally.

Therefore, the main object of the present invention is to provide a magnetic recording and reproducing apparatus that can reproduce at high speed and obtain good reproduced images even when the H arrangement is not established.

FIG. 2 is a diagram showing the head arrangement according to an embodiment of the present invention. In FIG. 2, heads 11 and 2 for normal recording and reproduction serve as reference heads and are arranged in the same manner as in FIG. 1.

An R azimuth head 5 and an azimuth head 7 are arranged on one rotational direction side and the other rotational direction side of the drum 10 from the head 1, and an R azimuth head 6 is arranged on one side of the head 2. In the case of still playback, field still playback is performed using the R azimuth head 5°6.

On the other hand, in the case of slow playback, R azimuth head 5, R
By switching the heads in the order of azimuth head 6.1 and azimuth head 7, field still playback and normal playback can be repeated, and field slow playback can be realized. Record when performing high-speed playback, so-called speed search.

Playback heads 1 and 2 are not dedicated heads for each of the two tape speed modes, so in either tape speed mode, the track width is wider than the head width (
This causes an unrecorded part (gart band). Therefore, as the magnetic tape traverses the head, a wide noise is generated. Furthermore, when the horizontal synchronization signals are shifted between adjacent tracks, that is, when the H arrangement is not established, skew distortion appears in the noise.

Therefore, the embodiment of the present invention has an R azimuth head of 2.6
The respective intervals of 1.58 (H is the interval of the horizontal synchronizing signal period) are selected, and azimuth head 1 and R azimuth head 5 and L azimuth head 1 and L azimuth head 7 are selected.
The interval between each is chosen to be 1°5H.

In tape speed mode where H arrangement is established, R
If you use azimuth head 2 and L azimuth head 1, or R azimuth head 6 and R azimuth head 5, or use either R azimuth head 6 or L azimuth head 7, whichever head has the larger reproduction output, noise will occur. It is possible to perform high-speed playback with less noise. In the tape speed mode where the H alignment is not established (if there is a deviation of 0.58), the R azimuth head 2 and the L azimuth head 1.5 days apart from the L azimuth head 1 to correct the H alignment. 7, or by selecting the R azimuth head 6, L azimuth head, or head 1, whichever has a larger reproduction output, high-speed reproduction without skew distortion and with less noise can be performed.

FIG. 3 is a diagram showing a head switching circuit for switching the heads arranged as shown in FIG. 2. First, the structure shown in FIG. 3 will be explained. Each head 1, 2 shown in FIG. 2 above
．． Outputs 5 and 7 are head amplifiers 8 and 1, respectively.
2 and amplified. The output of the head amplifier 8 is given to a signal processing circuit 20. The output of the head amplifier 9 is given to one input of an amplitude detector 13 and a head switch 16. The output of the head amplifier 10 is connected to the amplitude detector 14 and the head is turned off! It is given to the other input of IW16.

The output of the head switch 16 is given to a signal processing circuit 20. The amplitude detectors 13 and 14 detect the amplitudes of the read signals read by the azimuth head 1 and the L azimuth head 7, respectively.

The outputs of the amplitude detectors 13 and 14 are then given to an amplitude comparator 15. The amplitude comparator 15 determines which of the L azimuth heads 1 and 7 outputs a signal with a higher level.

The output of the amplitude comparator 15 is used as a switching signal for switching the head switching device 16, and is also connected to one input terminal of the head switching device 19 and sent to the other input terminal of the head switching device 19 via an inverting circuit 18. connected to the end.

The respective outputs of the head amplifiers 11 and 12 are connected to one input and the other input of the head switch 17. This head switch 17 is switched by the output of the head switch 19 described above. Then, the read output of the R azimuth head 2 or 6 switched by the head switch 17 is given to the signal processing circuit 20. The head switch 19 mentioned above is H
Input terminal 2 when in speed mode where no alignment is established.
It is switched by a signal given to 0.

Next, the head switching operation will be described with reference to FIGS. 2 and 3. First, in the case of the tape speed mode in which the H arrangement is established, no switching signal is applied to the 'input terminal 20. For this purpose, the Herad switch 19 is switched to the amplitude comparator 15 side. In this state, the outputs of L azimuth head 1 and L azimuth head 7 are each amplified by head amplifier 9.10, and amplitude detector 13.1
4, the amplitude comparator 15 compares the magnitude of each amplitude. Based on the output of the amplitude comparator 15, head switching devices 16 and 17 are respectively switched.

These head switchers 16 and 17 allow the combination of L azimuth head 1 and R azimuth head 2 or R
One of the pairs of azimuth head 7 and R azimuth head 6 is selected. Then, the output of the head with the larger reproduction output is given to the signal processing circuit 20.

In tape speed mode where H alignment is not established,
A switching signal is applied to the input terminal 20. This switching signal causes the head switch 19 to switch to the inverting amplifier 18 side. For this purpose, based on the comparison output of the amplitude comparator 15, the azimuth head 7 is shifted by 1.5 days from the L azimuth head 1 in order to correct the R azimuth head 2 and H alignment.
or the combination of the R azimuth head 6 and the azimuth head 1 shifted by 1.5H from the R azimuth head 5, whichever combination has the largest reproduction output is selected. That is, in the case of the tape speed mode in which the H arrangement is not established, any combination of R azimuth head 2 and L azimuth head 7 or R azimuth head 6 and azimuth head 1 is selected. Of the selected heads, the R azimuth head 6 and the L azimuth head 7 are the reference R azimuth head 2.
Since it is shifted by 1.5H with respect to the L azimuth head 1, it is possible to achieve high-speed reproduction without skew distortion and with little noise.

As described above, according to the present invention, a plurality of magnetic heads are arranged such that the interval between them is an odd multiple of 1/2 of the horizontal synchronization signal period with respect to the reference head, and the signal detected by each magnetic head is Since the amplitude level is determined and the magnetic head with the highest amplitude level is selected, high-speed playback with no skew distortion and low noise is achieved even in tape speed mode where H alignment is not established. can do.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of heads in a conventional magnetic recording/reproducing device. FIG. 2 is a diagram showing the head arrangement according to an embodiment of the present invention. FIG. 3 is a diagram showing a head switching circuit according to an embodiment of the present invention. In the figure, 1.7 is the azimuth head, 2°5.6 is the R azimuth head, 8 to 12 are the head amplifiers, and 13 is the azimuth head.
．． 14 is an amplitude detector, 15 is an amplitude comparator, 16.17.
19 is a head switch, and 18 is an inverting amplifier. Agent Shin Kuzuno - (1 other person)

Claims (2)

[Claims] (1) A magnetic recording and reproducing device having a plurality of magnetic heads including a special reproduction head for reproducing information recorded on a magnetic tape in a special state, wherein the interval between each of the plurality of magnetic heads is a standard. The magnetic heads are arranged so as to correspond to an odd multiple of 1/2 of the horizontal synchronization signal period relative to the head, and the amplitude level of the signal detected by each of the magnetic heads is determined, and the magnetic head with the largest amplitude level is selected. A magnetic recording and reproducing device equipped with means. (2) Each of the plurality of magnetic heads includes: a pair of reference heads disposed facing each other, and each of the plurality of magnetic heads having a width of 1/1 of the horizontal synchronization signal period on one side with respect to each of the pair of reference heads. first and second magnetic heads disposed opposite to each other with an interval of an integral multiple of 2; and 1/2 of the horizontal synchronization signal period on the other side of one of the pair of reference heads. 2. The magnetic recording and reproducing apparatus according to claim 1, further comprising a third magnetic head arranged at an interval that is an integral multiple of .