JPH04132383A - Magnetic recorder and reproducer - Google Patents

Abstract

PURPOSE:To prevent a black torn by switch an output from a reproducing equalizer according to the two kinds of formats modulated and recorded by different FM conveying waves. CONSTITUTION:A signal passing through a video frequency amplifier 21 for VHS and a low-pass passing filter 22 for VHS is selected by a switch 27 at the time reproducing a VHS tape, so that the signal obtained by amplifying the lower side band wave and upper side band wave of the video frequency for VHS to be well-balanced, can be supplied to a double limiter 12. And also, the signal obtained by sufficiently attenuating the unnecessary lower side band wave by a high-pass passing filter 24 for S-VHS, and amplifying the video frequency band for S-VHS by a video frequency amplifier 25 for S-VHS, at the time of reproducing an S-VHS tape, can be supplied to the double limiter 12. Thus, a reproduced picture without any black torn can be outputted.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention can record a luminance signal using only one type of FM carrier wave, but can reproduce luminance signals in two formats modulated and recorded using different FM carrier waves. It mainly relates to consumer magnetic recording and reproducing devices (hereinafter referred to as VTRs).

Below conventional technology, 3.4 MH2 to 4.4 MH2 (7) F is a typical VTR that can only record using one type of FM carrier wave.
A VHS format in which FM modulation and demodulation of a luminance signal is performed using M carrier waves will be explained. Further, the format for performing FM modulation and demodulation of the luminance signal using another reproducible FM carrier wave is assumed to be 5-VH3, which has an FM modulation band of 5.4 MH2 to 7.0 MH2. In other words, it is possible to record and play back tapes in VHS format, but not in 5-VH3 format.
R will be explained below.

Even if a conventional VHS format VTR (hereinafter referred to as normal VTR) tape recorded with 5-VHS tape is played back, it cannot output normal playback images due to the difference in format. Ta.

On the other hand, some manufacturers simply output reproduced images by switching the reproduction signal processing of a normal VTR during reproduction of a 5-VHS format tape. However, unlike the original 5-VH3 playback process, this is performed using the normal VTR playback process, so the original 5-VH3 image quality cannot be provided.

Hereinafter, this function will be referred to as simple S playback.

Hereinafter, the above-mentioned simple S playback will be explained with reference to the drawings.

Figure 2 is a block diagram showing signal processing (hereinafter referred to as RF processing) up to FM demodulation of the reproduction signal from the magnetic head, which is part of the luminance signal processing necessary for conventional simple S reproduction. It is something. In FIG. 2, a head amplifier 1 is configured to output a weak reproduction signal from 0 to I obtained from a magnetic head.
Amplify the band before OMH2. The FM video frequency amplifier 2 connected to the head amplifier 1 includes a series circuit consisting of a coil 3.4, a capacitor 5.6, and a switch 7.8, each of which is connected to the ground.

Further, a low-pass filter 9 is provided at the next stage of the FM video frequency amplifier 2, and a switch 10 for bypassing the low-pass filter 9 is provided at both input and output ends of the low-pass filter 9. The FM video frequency amplifier 2 and the low-pass filter 9 constitute a reproduction equalizer 11. Reference numeral 12 denotes a double limiter provided at the next stage of the low-pass filter 9, and its name will only be used here.

The operation of the RF processing of the S simple playback configured as described above will be described below. First, the FM video frequency of the brightness signal recorded in VHS format is NTS
C method, 3.4 MH2~4゜4 VH2 Te, 5
-VH3 (7) (-tllt5.4 MH2~7.0V
It is H2. The reproduced signal from the magnetic head whose band up to IOM HZ has been amplified by the head amplifier 1 is further amplified only for the FM video frequency component by the FM video frequency amplifier 2. In other words, if the tape being played back is a tape recorded in VHS format, the switch 7 becomes conductive and the frequency determined by the coil 3 and capacitor 5 (
4VH2~5MH2) center 11m V HS (7)
The FM video signal (luminance signal) is amplified. If the tape to be played back is a tape recorded in the 5-VHS format, the switch 8 is turned on and the frequency determined by the coil 4 and capacitor 6 (7VH
2), the 5-VH3 FM video signal (luminance signal) is amplified.

Next, the F of the VH3 amplified by the FM video frequency amplifier 2 is
In order to balance the sidebands of the M video signal, it passes through a low pass filter 9 to remove high frequency components. On the other hand, 5-VH
Since the FM video signal No. 3 has a high frequency, when it passes through the low-pass filter 9, the signal component itself is removed, so the switch 10 is made conductive to bypass it.

In this way, the switch 7.8 switches the amplification frequency of the FM video frequency amplifier 2, and the low-pass filter 9 is turned on and off to switch the playback equalizer characteristics, amplifying the FM video frequency and transmitting it to the next stage double limiter. 12.

Problems to be Solved by the Invention However, with the above conventional configuration, when a 5-VHS tape is played back, the upper and lower sidebands of the FM signal cannot be well balanced, and the portion of the screen that rises from black to white. In this case, black blurring occurs in which the originally white part is reversed to black.

This black blur will be explained using FIGS. 3(a) to 3(d). The waveform a in Fig. 3(a) is the playback signal waveform of the amplified head amplifier l output in the band up to 10VH2, and the waveform in Fig. 3(b) is the playback signal waveform of the playback equalizer when playing a VHS format tape. Waveform C in FIG. 3(C) is the output waveform of a conventional playback equalizer during playback of a 5-VHS format tape.
The waveform d) in d) is an output waveform of a reproduction equalizer that has a balanced upper sideband and lower sideband, with little black blurring during reproduction of a 5-VHS format tape.

In the conventional reproduction equalizer 1 shown in FIG. 2, only the amplification frequency of the FM video frequency amplifier 2 is switched, so as shown in FIG. It became too wide, causing black blurring due to imbalance with the upper sideband wave.

Therefore, the waveforms in FIGS. 3(b) and 3(d),
In order to satisfy both requirements d and d, conventional systems have had the problem of complicating switching and increasing the scale of the circuit.

The present invention is intended to solve the above-mentioned conventional problems, and an object of the present invention is to provide a VTR that has a simple configuration and can eliminate black blurring.

Means for Solving the Problems In order to solve the above problems, the VTR of the present invention performs FM modulation and demodulation as a magnetic recording and reproducing process for the luminance signal of the video signal, and records the luminance signal using only one type of FM carrier wave. Is the luminance signal modulated and recorded in two formats using different FM carrier waves?In a reproducible VTR, is the luminance signal modulated and recorded using FM carrier waves in the two formats reproduced from a magnetic head? A reproduction equalizer is provided for each of the two types of formats, and a switching means is provided that can switch the output from the reproduction equalizer according to the two types of format.

Effect: With the above configuration, the output from the playback equalizer provided for each of the two formats can be switched according to the two formats using the switching means, so that the output can be independently ideal for the two formats. This makes it easy to set the characteristics of the playback equalizer, which makes it possible to perform simple S playback with a simple configuration and less blurred black.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of RF system processing compatible with S simple playback in a VTR showing an embodiment of the present invention. Components that have the same functions and effects as those of the conventional example are given the same reference numerals, and their explanations are omitted. do. In FIG. 1, a VH3H3 video frequency amplifier 21 is connected to the output end of the head amplifier 1 that amplifies the weak signal obtained from the reproducing magnetic head over the entire frequency band. Amplify. Video frequency amplifier 21 for VH3H3
A VH3 low-pass filter 22 connected to the power end attenuates unnecessary high-frequency components. A VH3 reproduction equalizer 23 is configured by a VH3H3 video frequency amplifier 21 and a VH3 low-pass filter 22. Further, the 5-VH3 high-pass filter 24 connected to the output end of the head amplifier 1 sufficiently attenuates unnecessary lower sideband waves of the 5-VH3 video frequency. The 5-VH8 video frequency amplifier 25, which is the next stage of the 5-VH3 high-pass filter 24, is a 5-VH8 video frequency amplifier 25.
3 Amplify the video frequency band. A low-pass filter 22 for VH3 and a video frequency amplifier 25 for 5-VH3H3 constitute a simple S reproduction equalizer 26. Low-pass filter 22 for VH3 and video frequency amplifier 2 for 5-VH3H3
The switches 27 connected to the 5 output terminals are configured to switch between the output signal of the VH3 low-pass filter 22 and the 5-VH3H3 video frequency amplifier 25 output signal, and connect the output signal to the double limiter 12.

The operation of the S simple playback compatible RF system configured as described above will be described below. First, when playing a VHS tape, the VH3H3 video frequency amplifier 21
The signal that has passed through the low-pass filter 22 is sent to the switch 27.
By selecting , it is possible to supply the double limiter 12 with a signal in which the video frequency of VH3 is amplified with a well-balanced lower side band and upper side band. Also, when playing back a 5-VHS tape, the S, -V HS high-pass filter 2
4 to sufficiently attenuate the unnecessary lower sideband waves, 5-VH3
A signal obtained by amplifying the 5-VH3 video frequency band from the H3 video frequency amplifier 25 is supplied to the double limiter 12, and a reproduced image without black blur is output.

Effects of the Invention As described above, according to the present invention, ideal playback equalizer characteristics can be easily set independently for two types of formats, and can be switched according to the two types of formats. , it is possible to eliminate black blurring with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram of RF system processing for S easy playback in a VTR showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional VT
FIGS. 3A to 3D, which are block diagrams of RF system processing compatible with S simple playback in R, are output waveform diagrams of the main parts of FIG. 2 for explaining black blurring. 21...VH3 video frequency amplifier, 22...VH
3 low-pass filter, 23...VH3 reproduction equalizer, 24...5-VH3 low-pass filter, 25.
...5-VH3 video frequency amplifier, 26...Simple S
Playback equalizer, 27...switch.

Claims (1)

[Claims] 1. FM modulation and demodulation is performed as a magnetic recording and reproducing process for the luminance signal of the video signal, and the luminance signal can only be recorded using one type of FM carrier wave, but the luminance signal in two formats modulated and recorded using different FM carrier waves. A magnetic recording and reproducing device capable of reproducing signals, wherein a reproduction equalizer for a luminance signal modulated and recorded by an FM carrier wave of the two formats, which is reproduced from a magnetic head, is provided for each of the two formats, and A magnetic recording and reproducing apparatus provided with a switching means capable of switching output from a reproduction equalizer according to the two types of formats.