JPS6337806A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To obtain excellent reproduced picture quality for each mode by using the optimum head resonance for the mode B and using a circuit after a head amplifier so as to cancel the peaking by the head resonance in the mode A reproduction. CONSTITUTION:The peaking by the head resonance compensating the high frequency reduction in the magnetic head output is applied so as to optimize the head resonance comprising a magnetic head 1, a capacitor C, a resistor R and a rotary transformer 2 for the mode B where the FM carrier frequency of a luminance signal is modulated with higher frequencies. In case of the mode B, a switch 7 is thrown to the position of a terminal (b) to allow an equalizer 5B to obtain the optimum head resonance. While the switch 7 is thrown to the position of a terminal (a) at the mode A where the spectrum arrangement is given by (a) in figure so as to allow an equalizer 5A to cancel the peaking by the head resonance of the mode B thereby obtaining the optimum head resonance to the mode A.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic reproducing apparatus, and more particularly, to a magnetic reproducing apparatus that reproduces signals recorded in two modes with different recording spectrum arrangements using the same magnetic head.

BACKGROUND OF THE INVENTION Conventionally, as shown in FIG. 9(A), a frequency-modulated luminance signal YA and a low 1ii! Recording of the converted color signal C is performed in a VTR or the like. However, the progress of recording media in recent years has been remarkable, as shown in the figure (
As shown in B), it is considered to improve the B1 degree before horizontal by increasing the FM carrier frequency of the luminance signal YL3 and recording it. Here, performing recording and reproducing according to the spectrum arrangement shown in FIG. 13 (Δ) will be referred to as A mode, and performing recording and reproducing according to the spectrum arrangement shown in FIG. 12B as 8 mode.

The present invention relates to a magnetic reproduction apparatus capable of reproducing both the A mode and B mode.

FIG. 8 shows a circuit diagram of an example of a conventional device. In the figure, a signal reproduced by a magnetic head 1 is taken out from an output terminal 4 via a rotary transformer 2 and a head amplifier 3.

In this case, the inductance L caused by the magnetic head 1 and the rotary transformer 2 and the capacitor C provided on the input side of the head amplifier 3 create resonance, and by adjusting the resonance point near the lower limit of the FM carrier, various losses can be reduced. Compensation for the drop in high frequency output is being carried out. Note that the resistor R is a resistor for adjusting Q damping of head resonance.

Here, for the A mode, for example, the head resonance is as shown in FIG. 9(C), and for the B mode, for example, the head resonance is as shown in FIG. 9(D).
The head resonance shown in FIG.

Problems that the invention aims to solveHowever, when a recording medium recorded in A mode is reproduced using a magnetic reproducing device whose head resonance is tuned to 8 modes, the frequency of the resonance point is too high for the FM carrier. Therefore, there is a problem in that noise is emphasized, and image quality deteriorates due to head resonance.

On the contrary, when reproducing a recording medium recorded in B mode with a magnetic reproducing device whose head resonance is tuned to A mode, the frequency of the resonance point is too low for the FM carrier, so compensation is required. There was a problem in that the desired high-frequency output was not emphasized, but instead the low-frequency side was emphasized, resulting in a so-called inverted tax phenomenon.

To solve this problem, for example, it may be possible to provide a circuit between the rotary transformer 2 and the heater pad 3 to switch between A and B, but such a circuit is not suitable for the part that handles low-level signals. It is not preferable to provide this in terms of the signal-to-noise ratio.

The present invention uses the optimum head resonance for the B mode, and attenuates the peaking band due to the head resonance during A mode reproduction, thereby obtaining the optimum head resonance for each mode, and achieving the optimum head resonance for both modes. It is an object of the present invention to provide a magnetic reproducing device that can obtain good reproduced image quality.

Means for Solving the Problems In FIG. 1, a magnetic head 1, a capacitor C1, a resistor R
a first circuit that performs peaking by head resonance so as to compensate for a drop in the high frequency range of the output of the reproducing magnetic head when reproducing a recording medium recorded with the first spectrum arrangement;
The A-mode equalizer 5A is a second circuit that attenuates the peaking band after being amplified by the head amplifier when reproducing a recording medium recorded with the second spectrum arrangement.

By using the optimum head resonance for operation B mode, and attenuating the peaking band due to the head resonance with the A mode equalizer f5A installed after head amplifier 3 during Δ mode playback, A7-C and B mode to get good playback quality.

Embodiment FIG. 1 shows a circuit diagram of a first embodiment of the apparatus of the present invention. In the same figure, capacitor C1 resistor R, rotary transformer 2
It is assumed that the head resonance is adjusted to the characteristic shown in FIG. 9(D), which is optimal for eight modes.

The specific circuit diagram for the A-mode equalizer 5 is shown in Figure 2 (,
). Conventionally, a peaking circuit connected to the collector and emitter of a VTR, for example, performs the peaking shown by the arrow in the same figure (B) to compensate for the drop in the high range of the reproduction band, and further increases the high range as shown in the figure (B). The one with the characteristics shown by the broken line is used. In this embodiment, a trap circuit 6 surrounded by a broken line in FIG. 12A is provided, and its trap frequency is set to fX near the frequency of peaking due to head resonance, and the characteristics are as shown by the solid line in FIG.

This cancels out peaking due to head resonance in B mode. In the figure (B), α is the FM carrier frequency in A mode.

A specific circuit diagram of the B-mode equalizer 511 is shown in Figure 3 (
Shown in A). This one does not use a trap circuit like the A-mode equalizer 5A, and its characteristics are as shown in the figure (
It is considered as shown in B). In the figure (B), β is the FM carrier frequency in B mode.

In FIG. 1, in the A mode, switch 7 is connected to terminal a, and equalizer 5A compensates for peaking due to head resonance with the frequency characteristics shown by the solid line in FIG. 2(B). On the other hand, in the B mode, the switch 7 is connected to the terminal B, and the equalizer 5B obtains optimum head resonance with the frequency characteristics shown in FIG. 3(B).

In addition, the equalizer 'f5A for A mode is shown in Figure 2 (
It is not limited to what is shown in A).

For example, in FIG. 2<A), the trap circuit 6 is omitted, and its output terminal 5AO is used as shown in FIGS. 4(A) and 4(B).

A trap effect may be obtained by further connecting a circuit having the configuration shown in (C). In addition, the LC circuit can be used as shown in Figure 2 (
The frequency f× of B) may have a trap characteristic.

Further, it is not necessary to provide separate equalizers for A-t-mode and B-mode, and it is also possible to use one equalizer and switch it for each mode. In this case, a switch may be provided to open one end of the trap circuit 6 shown in FIG. 2 (A>) in the B mode.

FIG. 5 shows a circuit diagram of a second embodiment of the device according to the invention. In the same figure, the A-mode equalizer 5A' has, for example, the characteristics as shown in FIG.
I! (has no wrap property to L+). Further, as shown in FIG. 6, the low-pass filter 8 has a characteristic that the attenuation region occurs near the frequency afx shown in FIG. 2(B). In this way, A
By using the mode equalizer 5Δ' and the low-pass filter 8 in combination, it is possible to obtain substantially the same characteristics as the first embodiment shown in FIG.

4i. Also, as the equalizer for mode A in the second embodiment, an equalizer with characteristics having a Hatake area trap as shown by the solid line in FIG. good.

In addition, in FIG. 5, riser 5 for A7-
It is not necessary to provide two clearly differentiated circuits like the low-pass filter 8 and the low-pass filter 8, and the overall frequency characteristic is, for example, relative to the FM carrier frequency in the A mode, as shown in FIG. It is also possible to provide a circuit that is sufficiently attenuated in the vicinity of x at the frequency.

Effects of the Invention According to the device of the present invention, the optimum head resonance is used for the mode according to the first recording spectrum arrangement, and when reproducing the mode according to the second recording spectrum arrangement, the circuit provided after the head amplifier performs the head resonance that is most suitable for the mode according to the first recording spectrum arrangement. Since the Beyoung caused by head resonance is canceled, it is possible to obtain optimum head resonance for each mode, and it has the advantage of being able to provide good image quality for each mode.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of the first embodiment of the device of the present invention, and Figure 2 is △
Circuit diagram and characteristic diagram of mode equalizer, Figure 3 i, t
A circuit diagram and characteristic diagram of an equalizer for B mode, Fig. 4 is a circuit diagram of an embodiment of the present invention for obtaining trap characteristics, Fig. 5 is a circuit diagram of a second embodiment of the present invention, and Fig. 6 is a circuit diagram of an embodiment of the present invention. A characteristic diagram of the low-pass filter, No. 71 is a characteristic diagram of a circuit for obtaining frequency range 1 in A mode, FIG. 8 is a circuit diagram of an example of a conventional device, and FIG. 9 is a spectrum arrangement for each recording mode. It is a figure for explaining. 1...Magnetic head, 2...Rotary transformer, 3.
・・l\tudoamp, 4...output terminal, 5A, 5A'
...Equalizer for A mode, 5B...Equalizer for B mode, 6...Trap circuit, 7...Switch, 8...Low pass filter, C...Capacitor, R...
·resistance. Patent applicant Victor Company of Japan Co., Ltd. 'l
l' sheet Figure 8 Figure 9

Claims (4)

[Claims] (1) A first circuit that performs peaking by head resonance to compensate for a drop in the high frequency range of the reproduction magnetic head output when reproducing a recording medium recorded with the first spectral arrangement, and a second spectral arrangement. 1. A magnetic reproducing apparatus comprising: a second circuit that attenuates the peaking band after amplifying it with a head amplifier when reproducing a recorded recording medium. (2) The magnetic reproducing device according to claim 1, wherein the second circuit is provided with an equalizer having a trap characteristic that substantially cancels out the peaking. (3) The magnetic reproducing device according to claim 2, wherein the equalizer also has frequency characteristics that compensate for a drop in the high frequency range of the reproduction band in the second spectrum arrangement. (4) The magnetic field according to claim 1, wherein the second circuit is provided with a low-pass filter whose attenuation range is the frequency at which the peaking is performed, after the output of the head amplifier. playback device.