JPS61264981A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain reproduction of a tape recorded by a VTR of conventional standard to be reproduced without any breakage or deterioration in S/N at a VTR with high resolution by providing a switch part of RF signal, BPF part, detector circuit part, comparator part, data-holding part, timing circuit part, and a mode-switching part. CONSTITUTION:At a conventional standard VTR, because no output is supplied to a band pass filter 3, the output of a comparator 13 goes to low level. At a high resolution VTR, the output of the comparator 13 goes to high level. Therefore, above-mentioned two are identified with each other. Using this output from the comparator 13, the switchings of picture carrier, white clip, and of dark clip are executed by a mode switch 16. Furthermore, by driving an LED 18 with a transistor 20, the discrimination of a tape and its display are executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording and reproducing apparatus such as a video tape recorder, which is designed to improve image quality by opening a video carrier or the like.

BACKGROUND OF THE INVENTION In recent years, video tape recorders (hereinafter referred to as V
There is a demand for higher image quality of VTRs (abbreviated as TR), and various companies are developing high-resolution VTRs. Regarding higher resolution, (1) I would like to mention video carriers. (11) Raise the white clip and dark clip. (iii) Countermeasures such as widening the band of the filter and changing the peaking frequency of the fIVIRF system have been taken.On the other hand, countermeasures have been taken such as changing the emphasis amount of the luminance signal to deal with the deterioration of S/N due to raising the carrier. is commonly applied.

However, with the above configuration, the conventional standard (7)
When a tape recorded on a VTR (e.g. VH3M rated VTR, etc.) is played back on the high resolution VTR, the peaking frequency of the RF (radio frequency) system is different, so the S/N ratio may deteriorate or white clips may occur. Since the tapes are different, there are problems such as "blemishing" is likely to occur, and it is impossible to determine whether the tape being played back is a conventional standard tape or a tape recorded with a high-resolution VTR.

In view of the above-mentioned problems, the present invention provides a magnetic recording and reproducing apparatus that distinguishes whether a tape is recorded on a conventional standard VTR or a high-resolution VTR, and switches and displays various modes. That is.

Means for Solving the Problems In order to solve the above-mentioned problems, the magnetic recording and reproducing apparatus of the present invention includes a switch section that switches according to a small RF output, a vertical synchronization signal, or a horizontal synchronization signal of a video tape recorder, and the switch section. A bandpass filter that extracts the required band for small RF output after switching by , a detection circuit that detects the output of the bandpass filter, a comparison section that compares the output of the detection circuit with a reference voltage, and an output of the comparison section. a data holding section that holds the data holding section, a timing section that determines the timing of the data holding section, a mode switching section that switches the mode according to the output of the data holding section, and a display section that displays the output of the data holding section. It is constructed with the following features.

Effect of the Invention With the above-described configuration, the present invention enables tapes recorded in the conventional standard "/TR" to be played back on a high-resolution VTR, and it is also possible to distinguish and display tapes.

Embodiments Hereinafter, magnetic recording and reproducing apparatuses according to embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the main circuit configuration of an embodiment of the present invention. In Fig. 1, 1 is a switch circuit into which the RF multiplied signal of the VTR is input, 2 is a buffer amplifier, 3 is a band pass filter (B, P, ?), 4 is an amplifier, 6 is a buffer amplifier, 6 is a coupling capacitor, 1 is a detection circuit including diodes 8a and 8b, a capacitor 9, and a resistor 1o.
1. 12 is a resistor for creating the reference voltage E8, 13 is a comparator, 14 is a timing circuit, and 16 is a D type flip-flop (D, F, F) that is a data holding section.
circuit, 16 is a mode selection switch, 17 is a base resistor,
18 is a light emitting diode (LED) for display, 19 is a current limiting resistor, and 20 is a transistor for driving the LED. The magnetic recording/reproducing apparatus of this embodiment configured as above will be described below in FIGS. 1 and 2. The operation will be explained using figures.

First, FIG. 1 shows a circuit for identifying whether the VTR is a conventional standard VTR or a high-resolution VTR, and a switching circuit. FIG. 2 shows signal waveforms and timing at each part at that time.

In Figure 1, RF
The signal is input to the double signal switch circuit 1 and switched using a vertical synchronizing signal or a horizontal synchronizing signal (the following explanation will be based on a vertical synchronizing signal for the sake of simplicity). The output is passed through a buffer amplifier 2 to a bandpass filter 3.
Enter. This bandpass filter 3 converts the center frequency into an FM signal corresponding to the sync chip of a high-resolution VTR.
Set to the modulation frequency, and use a filter with a narrow band and steep characteristics. This output [see Fig. 2 (see cl)] is passed through the amplifier 4, the buffer amplifier 5, the entire detection circuit 7, and detected [Fig. 2 (see dl]).Then, the detected output is sent to the comparator 13 The clock of the OD flip-flop circuit 15 is generated from the falling edge of the vertical synchronization signal by the timing circuit 14, and the comparator output [see el in FIG. 2] is sent to the D flip-flop circuit 16. Make sure that the rising edge comes at about half the width of the vertical synchronization signal [see Figure 2 (see fl)]
.

Therefore, the comparator output is held at the rising edge of the D flip-flop circuit 15 until the next vertical synchronizing signal arrives.

In this way, in conventional standard VTRs, there is no output to the bandpass filter 3, so the comparator output is low (L
ow) level, and on a high-resolution VTR, the level shown in Figure 2 (e
Identification is possible because the comparator output is at a high level, as shown in 1. With this output, the mode changeover switch 16 is used to change the video carrier, white clip, dark clip, etc. Further LE
DlB is driven by the transistor 2o, and a tape discrimination 9 display is performed.

As described above, according to this embodiment, the RF doubler signal switch section, the bandpass filter section, and the detection circuit section.

By providing a comparison section, data holding section, timing circuit section, mode switching section, and display section, it is possible to
Tapes recorded on high-resolution VTRs are also blurred and S
/N can be played back without deterioration, and it can be determined by the display unit whether the tape being played back is a tape recorded in accordance with the conventional standard or a tape recorded on a high-resolution VTR.

Next, other embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a circuit diagram of a main part of a magnetic recording/reproducing apparatus showing a second embodiment of the present invention.
21 is a buffer amplifier, 22 is a band pass filter, 2
3 is an amplifier, 24 is a buffer amplifier, 26 is a coupling capacitor, 26 is a diode 2a, 27b and a capacitor 2
8 and a resistor 29. The relationship is the same as that in Figure 1. That is, the difference from the configuration shown in FIG. 1 is that the reference input (El) of the comparator 13 is obtained by the detection output of a steep bandhus filter 22 that passes only the FM modulation frequency corresponding to the sync chip of a conventional standard VTR. The point is that there is.

The operation of the magnetic recording/reproducing apparatus of this embodiment configured as described above will be described below. As mentioned above, the bandpass filter 3 sets the center frequency f to the high-resolution VTR.
The center frequency f2 of the bandpass filter 22 is set to the 2M modulation frequency corresponding to the sync chip of a conventional standard VTR. Therefore, when playing back a tape recorded on a conventional VTR, comparator 13 (7) (+
The relationship between input E1 and input E2 is E,>E2, and the comparator output becomes low level. Also, high resolution VT
When playing back a tape recorded in R, comparator 1
If the relationship of 3 is input E+*''2, E+<Ez, and the comparator output becomes high level.

As described above, by providing the bandpass filter 22 whose center frequency is the FM modulation frequency corresponding to the sync chip of a conventional standard VTR, and using the signal detected from the output as the reference input of the comparator 13, two The detection outputs of the bandpass filters 3 and 22 can be compared relatively, and more reliable operation can be expected with respect to noise and the like.

Effects of the Invention As described above, according to the present invention, tapes recorded on a conventional standard VTR can be played back on a high-resolution VTR, and tapes can be distinguished and displayed. I can do it.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts of a magnetic recording and reproducing apparatus according to a first embodiment of the present invention, FIG. 2 is a signal waveform diagram of each part of FIG. 1, and FIG. 3 is a diagram of a second embodiment of the present invention. 1 is a block diagram of main parts of a magnetic recording and reproducing apparatus according to the present invention. 1...Switch Do path, 3.22...
Bandpass filter, 7.26...detection circuit,
13... Comparator, 14... Timing circuit, 15... Flip-flop circuit, 16
...Mode selector switch, 18...L
ED, 20... River/LED drive transistor. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure Ij) D, FF70 7ﾄ≦θ

Claims (1)

[Claims] A switch section that switches the RF output of the video tape recorder using a vertical synchronization signal or a horizontal synchronization signal, a bandpass filter that extracts the necessary band of the RF output after switching by the switch section, and a detection of the output of the bandpass filter. a detector circuit that compares the output of the detector circuit with a reference voltage, a data holding section that holds the output of the comparing section, a timing section that determines the timing of the data holding section, and a timing section that determines the timing of the data holding section. 1. A magnetic recording and reproducing device comprising: a mode switching section that switches modes depending on the output; and a display section that displays the output of the data holding section.