JPS637090A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To prevent degradation of the resolution of a chrominance signal in the vertical direction at the time of dubbing by conducting a reproduced chrominance signal to a chrominance signal output terminal for dubbing not through a crosstalk cancel circuit, and cancelling the crosstalk component by a means demodulating the low pass conversion chrominance signal into a com posite color video signal. CONSTITUTION:A crosstalk cancel circuit 6 isn't used at the time of dubbing. A low pass conversion chrominance signal whose crosstalk component isn't cancelled, that is, the low pass conversion chrominance signal where 1H of delay doesn't occur is supplied to a chrominance signal output terminal 16 for dubbing, so the chrominance signal having crosstalk is recorded on a mag netic tape. But when the dubbed magnetic tape is reproduced, as the low pass conversion chrominance signal the signal that the phase phi3 of the reproduced signal, the crosstalk component phi4 before dubbing and the crosstalk component phi5 which issues by being reproduced this time are piled like figure (g) is obtained. The signal delaying figure (g) is figure (h) and by composing figure (g) and figure (h) the crosstalk components phi4 and phi5 are cancelled, so that the signal whose crosstalk component is cancelled like figure (i) can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus for recording and reproducing composite color video signals using a rotating head without using a guard band.

Conventional technology In recent years, magnetic recording and reproducing devices have been used without using guard bands in order to achieve high-density recording. Solved by
The color signal recorded by low frequency conversion is phase shifted (VH8) 4
- Crosstalk components are canceled using matte) or phase inversion (beta format), but in order to maintain high image quality during dubbing and editing, the luminance signal and low frequency conversion color signal are transmitted and recorded separately. The method has been introduced into magnetic recording and reproducing devices.

FIG. 3 shows a recording and reproducing circuit for dubbing in the conventional magnetic recording and reproducing apparatus described above. 1 is a magnetic recording/reproducing device on the reproduction side, 2.3.4, 5.6, and 7.8 are reproduction heads, respectively.
These are a regenerative amplifier, a luminance signal demodulation circuit, a low acid pass filter, a crosstalk cancellation circuit, a luminance signal output terminal, and a chrominance signal output terminal. 9 is a recording side magnetic recording/reproducing device; 10
, 11, 12, 13, and 14.15 are a luminance signal input terminal, a luminance signal FM modulation circuit, a mixing circuit, a recording amplifier, a recording head, and a color signal input terminal, respectively.

A description will be given of spinning when dubbing using the conventional magnetic recording/reproducing apparatus configured as described above.

First, the luminance signal of the signal reproduced by the reproduction head 2 passes through the reproduction amplifier 3 and is demodulated into a video signal by the luminance signal demodulation circuit 4, and then passes through the luminance signal output terminal 7 and is output from the luminance signal input terminal 10 on the recording side for magnetic recording reproduction. Wave [enters 9, luminance belief @
The signal is FM modulated by an FM modulation circuit, passes through a mixing circuit 12 and a recording amplifier 13, and is recorded on a magnetic tape by a recording head 14. The color@moon is separated by a low-pass filter 5, and after crosstalk from adjacent tracks is removed by a crosstalk canceling circuit 6, it passes through a color signal output terminal 8 and is sent to a recording side magnetic recording/reproducing device 9 from a color signal input terminal 15. The signal is mixed with the luminance signal by the mixing circuit 12 and recorded.

Problems to be Solved by the Invention In the conventional configuration, crosstalk of adjacent tracks is canceled by a crosstalk canceling circuit 6 using an eleventh delay line, and then the color of the magnetic recording/reproducing device @1 on the reproduction side is canceled. Since the color signal is output to the signal output terminal 8,
On the dubbed magnetic tape, it can be recorded as a color signal component without cross daughters of adjacent tracks.Since the chrominance signal passes through the stalk cancellation circuit 6, a shift of 1H occurs in the color signal, so the vertical resolution of the β signal is reduced. It has the disadvantage of decreasing.

An object of the present invention is to provide a magnetic recording/reproducing apparatus in which the resolution of a color signal does not deteriorate as in the prior art even when dubbing is performed.

Means for Solving the Problems The magnetic recording and reproducing apparatus of the present invention converts the color signal of a composite color video signal into a low frequency band and records it, and upon reproduction, phase shifts or phase inverts the crosstalk signals from adjacent tracks. The present invention is characterized in that #4 is formed so that the reproduced color signal is guided to the dubbing color signal output terminal without going through the crosstalk canceling circuit.

According to this configuration, the low frequency conversion color signal is transmitted from the reproducing side magnetic recording/reproducing device to the recording side magnetic recording/reproducing device without canceling the zero stroke component, and is mixed with the 1III& signal and recorded on the magnetic tape. However, when the dubbed magnetic tape is reproduced, when the low frequency converted color signal is restored, the crosstalk components generated during the current reproduction and the previous crosstalk components are canceled.

Embodiment Hereinafter, a VHS format magnetic recording and reproducing apparatus according to an embodiment of the present invention will be explained with reference to FIGS. 1 and 2. Components having the same functions as those in FIG. 3 are given the same reference numerals and their explanations will be omitted.

FIG. 1 shows the connection state of the magnetic recording/reproducing apparatus of the present invention when dubbing is used, and differs from FIG. 3 only in the following points. In other words, in FIG. 1, the output of the low-pass filter 5 is directly supplied to the dubbing color signal output terminal 16, the crosstalk canceling circuit 6 is not used during dubbing, and the crosstalk canceling circuit 6 is connected to the TV. It is used when playing back onto a CRT of a John receiver (not shown).

Prior to explaining the operation of the present invention, the crosstalk cell operation of color signals in a conventional magnetic recording/reproducing device will be explained using FIGS. 2(a) to 2(f), and the present invention will be made clearer by comparison. .

FIG. 2(a) shows the phase of the low frequency conversion color signal of the track to be reproduced, and the phase is shifted by 90 degrees in the advancing direction from the 1st H, 2H, and 311th. FIG. 2(b) shows the phase of the low frequency conversion color signal recorded on the adjacent track,
The phase is shifted by 90 degrees in the lag direction at the 11th, 21st, and 31st positions. FIG. 2(C) shows a signal obtained when the signal in FIG. 2(a) is reproduced, and the two signals, the phase φ1 of the reproduced signal and the phase φ2 of the crosstalk component, are superimposed. Figure 2(d) is the demodulated signal of Figure 2(C) so that the phases of the reproduced signals are in the same direction.
Figure 2(e) is this signal delayed by a one-day delay line, and Figure 2(f) is the composite of the signals in Figures 2(d) and (e). . Conventionally, crosstalk is canceled in this way.

In contrast to the above conventional example, in the present invention, the crosstalk component is not canceled and the low frequency conversion 8@, that is, 111
Since the low-frequency converted color signal with a delay of 100 nm is supplied to the dubbing color signal output terminal 16, a color signal having crosstalk is recorded on the magnetic tape. However, when this dubbed magnetic tape is played back, the low frequency conversion color signal is as shown in Figure 2 (0), with the phase φ3 of the reproduced signal, the dubbing curve 0, the stroke component φ4, and the current reproduction. A superposition of the zero stroke component φ5 is obtained. This figure 2 (signal delayed from (1) is the second
In Figure (h), by combining Figure 2 ((+) and (h), the 0-stroke components φ4 and φ5 are phased, and the crosstalk component is canceled as shown in Figure 2 (1). You get what you get.

In this way, even if the color signal is extended by 8 times in the crosstalk cancellation circuit during dubbing, the crosstalk accumulated up to now can be eliminated by demodulating the low frequency converted color signal into a composite color video signal. It turns out that the ingredients can be canceled.

As described in detail, the magnetic recording/reproducing FI device of the present invention is configured so that the reproduced color signal is guided to the dubbing color signal output terminal without passing through the crosstalk canceling circuit.
By recording a color signal without IHill spread on a magnetic tape and demodulating the low frequency converted color signal into a composite color video signal by reproducing the dubbed magnetic tape, the crosstalk components that have been accumulated up to that point are canceled. can do. Moreover, when dubbing, the low frequency conversion color signal is 11
Since there is no delay, it is possible to avoid the conventional problem that the vertical resolution of the color signal decreases due to dubbing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of an embodiment of the magnetic recording/reproducing apparatus of the present invention showing the connection state when dubbing is used, and FIG. 2 is an explanatory diagram showing how crosstalk can be canceled.
FIG. 3 is a block diagram of main parts showing the connection state of a conventional magnetic recording/reproducing VC device when dubbing is used. DESCRIPTION OF SYMBOLS 1... Reproducing side magnetic recording/reproducing device, 2... Reproducing head, 3... Reproducing amplifier, 4... Luminance signal demodulator, 5...
...Low pass filter, 6...Crosstalk cancellation circuit, 7...Radiant signal output terminal, 16...Color signal output terminal for dubbing

Claims (1)

[Claims] 1. The color signal of the composite color video signal is converted to low frequency and recorded, and the crosstalk signal from adjacent tracks is canceled by phase shift or phase inversion during playback, and the reproduced color signal is configured to cancel the crosstalk signal. A magnetic recording/reproducing device configured to lead to a dubbing color signal output terminal without going through a circuit.