JPS63114481A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To maintain a high order compatibility in a high band recording VTR and select a recording mode without an error and automatically discriminate by providing a discriminating circuit for a tape for a high band and the conventional tape and a discriminating circuit for the high band of a selection switch of a recording system and a reproducing signal and the convention. CONSTITUTION:When a cassette 24 of the H tape is inserted into the main body 19 of a high band (H)-VTR, the movable protruding part 20 of a tape discriminating device 21 is not pushed due to the hole of the H tape 24 but a signal indicating the H tape is outputted from a terminal 22. Then, it is inputted to a terminal 4 to change over a switch 3, a luminance signal via the switch 5 is frequency multiplexed on a chromaticity signal in an adder 12 through an LPF for recording the high band, an FM modulator 7, a switch 8, and an HPF11 and recorded on a magnetic tape 18. Then, the signal is read by a head 17 for a video and a reproduced FM luminance signal inputted to a terminal 25 through a reproducing amplifier 39 and an HPF40 is discriminated in frequency in a frequency discriminator 32 to change over a switch 31 by this output, added to an adder 47 from a terminal 29, frequency multiplexed on the chromaticity signal and outputted to a terminal 51.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a magnetic recording and reproducing device (hereinafter referred to as V'r R).
In particular, the present invention relates to a VTR in which recording is performed using a magnetic tape suitable for recording high-frequency signals, with the carrier wave of the FM luminance signal set to a higher frequency than in the past.

[Conventional technology]

In current VHS type VTRs, video signals are recorded on a magnetic tape using a luminance signal FM modulation/chromaticity signal low frequency diversion multiplex recording method. That is, the luminance signal is ICFM modulated with a carrier frequency of 54~4.4 MHz, and the chromaticity signal is modulated with a subcarrier frequency of 54 to 4.4 MHz.
The low range is converted and recorded. Therefore, the transmission frequency band of the luminance signal is approximately 5 MHz, and the horizontal resolution is 240 MHz.
The limit is about a book.

As a means of improving horizontal resolution, a high-band recording method that shifts the carrier frequency of the luminance signal to a higher frequency side is used, as described in the May 1986 issue of the Journal of the Institute of Technology, Television, and Television, pages 56 to 39. Can be mentioned.

[Problem that the invention seeks to solve]

When applying the short-wave recording method to a VHS type VTR, a magnetic tape is required that can record signals at higher frequencies, that is, shorter wavelengths than conventional ones. Currently, at the prototype level, by means of high-density packing of magnetic powder,
Magnetic tapes that can be encoded at about 2 MHz have been produced.

By the way, the above-mentioned conventional technology does not include the application of the C/% Iband recording method using a new magnetic tape for exclusive 71 Iband recording, and the difference between the high band recording tape and the conventional recording tape is not addressed. .

There were problems with the determination of the data and compatibility with conventional recording methods.

An object of the present invention is to realize a system for automatically discriminating between a high-band recording tape and a conventional tape in a high-band recording VTR, and to realize a system for automatically distinguishing between a high-band recording tape and a conventional tape, and by switching the signal system circuit.
・Enables both i-band recording and conventional recording, and when playing back, it automatically determines whether it was recorded using i-band recording or conventional recording, and allows for high-level interchangeability. It is an object of the present invention to provide a means for improving image quality by applying no-band recording while maintaining the original image quality.

[Means to solve the problem χ]

The above objective is achieved by the following means.

First, magnetic tape for high-band recording is capable of short-wavelength recording and has excellent recording and reproducing characteristics for high-frequency signals. Shape features such as holes, grooves, protrusions, etc. that are not present in No. 1-7 are provided.

Second, a circuit is provided to detect the characteristics of the cassette half of the high-band recording tape.

Third, there is a switch that allows the user to select between high-band recording and conventional recording when recording. Depending on the output of the detection circuit, if high-band recording tape is to be used, either high-band recording or conventional recording can be arbitrarily selected depending on the position of this switch. In case, the position of the switch does not matter (traditional record?) to Naruko.

Fourthly, a circuit is provided for determining whether the reproduced signal is one that has been recorded using an electronic band or a conventional one, based on one frequency, at the time of reproduction.

[Effect]

By using a magnetic tape with excellent short-wavelength recording characteristics for high-band recording, the attenuation of high-frequency components of the recording signal is reduced, making it possible to perform no-band recording on a VH8 VTR. Incidentally, conventional recording on a high band tape is of course also possible.

High-band recording has the following advantages and can improve image quality.

(a) Resolution is improved by widening the band of the luminance signal.

(Interference between luminance signals and chromaticity signals is reduced.

(The realism effect increases and crosstalk from adjacent tracks decreases.)

First, by adding a characteristic to the cassette half of the high-band recording tape and installing a circuit to detect this characteristic in the high-band recording VTR, it becomes possible to automatically distinguish between high-band recording and conventional recording. By using this together with the above-mentioned cassette half-characteristic detection circuit, the user can select the desired switch sound pattern to create a high-band recording tape.

It becomes possible to perform recording using the recording method, and it is also possible to prevent high-band recording from being erroneously performed on a conventional tape. Furthermore, if a circuit for determining the frequency of the reproduced signal is provided, it becomes possible to automatically determine whether the signal recorded on the tape is high-band recording or conventional recording.

By using these automatic discrimination circuits, by switching the signal circuit in the VTR to high band mode or conventional mode, recording and playback can be performed using either method on a high band VTR, ensuring upward compatibility with conventional VTRs. You can do it.

〔Example〕

Below are drawings of embodiments of the present invention? I will explain using

FIG. 2 shows the frequency range χ of a video signal recorded on a magnetic tape. Figure 2 (a) shows the case of a conventional VHS type VTR, where the carrier frequency &4~t
4MHz KFM modulated luminance signal (Y signal) and subcarrier frequency 5.58MHz to 0.6.29MHz
! ' is frequency-multiplexed with the chromaticity signal (C signal) that has been low-pass converted and recorded. In this case, the band of the Y signal is approximately 3MHz
The horizontal resolution of the reproduced image is limited to about 240 lines.

On the other hand, in a simple embodiment of the present invention, the carrier frequency of the Y signal is set to 5.5 to 45M, for example, as shown in FIG.
Hz, and perform high band conversion to about 2 MHz. However, the C signal is low frequency converted as before. In this case, the band of the Y signal is about 5 MHz, and the horizontal resolution can be improved to about 400 lines.

However, with conventional magnetic tapes, it is difficult to record short wavelengths, so when a high band of approximately 2 MHz is performed, the high frequency components of the reproduced signal are greatly attenuated. Therefore, we use a magnetic tape for pie band recording that is newly capable of recording short wavelengths. Examples of high band tapes include vapor-deposited tape,
Metal tape or the like may be used.

VT assuming the use of such high band tape
If R is put into practical use, both VTRs and tapes will come in two categories: conventional standards and high-band standards.

An important condition for high-band VTRs and tapes is to ensure upward compatibility with conventional standard VTRs and tapes that are currently widely used.Hereinafter, we will explain how to ensure upward compatibility.

Figure 3 shows each combination of V'rR and tape for the conventional standard and high band standard. This shows the recorded and reproduced contents.

In the case of recording, high-band recording is possible only when a high-band tape (hereinafter referred to as H-tape and connector) is used in a high-band VTR (hereinafter referred to as H-VTR and connector).

Well, when a conventional tape is inserted into an H-VTR.

In order to prevent high band recording from being performed by mistake, the H-V
A tape discrimination function Z is provided in the TR.

For tape identification, for example, the H tape cassette half has holes and grooves that are not present in conventional tape cassettes.

Provide a geometrical feature such as a protrusion. Does H-VTR have this feature? Detect @ structure, depending on the presence or absence of characteristics) l-
Is the tape inserted into the VTR a conventional tape or an H tape?
Discern. As an example of this example, a hole is provided in the cassette half of the H tape? It is shown in Figure 4. (4) is H-VTR
(4) shows the cross section when the H tape cassette 24 is inserted into the main body 19 of the 1-VTR. The tape discrimination device 21 is equipped with a movable protrusion 20 that detects the presence or absence of a hole in the cassette half.
), there is no hole in the cassette half, so the protrusion 2o
is pushed in, and a signal indicating that the inserted tape is a conventional tape is output from the terminal 22. Also, (4)
In this case, the protrusion 20 is not pushed in because it hits the hole in the H tape 24, and a signal indicating that the inserted tape is an H tape is output from the terminal 22.

As a result, the H-VTR automatically inserts channel 1.
Z discrimination is performed, and in the case of H tape, high band recording is performed.
In the case of conventional tape, conventional recording is performed. However, in the case of H tape, a manual switch is provided that allows the user to arbitrarily select between high-band recording and conventional recording so that conventional recording is also possible according to the user's needs. On the other hand, since conventional VTRs cannot of course perform high-band recording, conventional recording involving tape is performed. In this way, when recording, tape, VT
Depending on the combination of recording methods, there are five types of recorded contents as shown in FIG.

Next, the case of reproducing a tape with these five recorded contents will be explained. These tapes may be played on H-VTR or conventional VTFL,
Depending on the combination of the tape and VTR during playback, there are ten playback results as shown in FIG.

During playback, conventional VTRs always perform conventional playback regardless of the recorded content of the tape, but H-VTRs have to switch between high-band playback and conventional playback according to the recorded content of the tape. A discrimination function is required. A circuit block diagram of an embodiment of this discrimination function is shown in FIG. 5(a).
, (phrase, shown in (6).

The embodiment shown in FIG. 5CeL) utilizes a tape discrimination circuit Y during recording, which will be described later with reference to FIG. 1, and the circuit can be simplified by sharing the same with the discrimination circuit during recording. switch 2
6 sorts the reproduced FM 4 degree signal inputted from the terminal 25 according to the output signal of the tape discrimination circuit inputted from the terminal 27. For H tape, the signal is applied to switch 28. The switch 28 is a manual switch with which the user determines the recording method by looking at the reproduced image and switches between high band and conventional. If the recording method is high band, terminal 29,
In the conventional case, the signal is output to the terminal 30. 1. -1
In the case of Junmai tape, the recording method is conventional recording, so
The signal is output from switch 26 to terminal 60.

FIG. 5 (4) is an example using a frequency discriminator 52,
Discrimination during playback can be automated. A frequency discriminator 32 determines whether the reproduced FM luminance signal inputted from the terminal 25 is a high band recorded signal or a conventionally recorded signal, and this output switches the switch 61 to determine whether the high band is It outputs to terminal 29, conventionally to terminal 50. Note that the frequency discrimination circuit 62 may be configured as shown in the block diagram shown in FIG. 6, for example. The luminance FM signal input from the terminal 35 is made constant in amplitude by the FMAGC circuit 54, and is applied to the BPF 55 and B1'F36. BPF5
5, for example, around 4MHz, and BPF56, for example, 6
Only signal components near MHz are extracted and level comparator 3
Added to 7. The level comparator 67 determines that if the output level of the BPF 55 is high, the reproduced signal is conventionally recorded;
If the output level is high, it is determined that high band recording is being performed, and the result is output to the N terminal 38.

FIG. 5(c) is a composite type of (a) and (4). The reproduced FM luminance signal inputted from the terminal 25 is switched by the switch 26 according to the output signal of the tape discrimination circuit inputted from the terminal 27. Only in the case of H tape, the signal is applied to the switch 51 and the frequency discrimination circuit 52, and in the case of high band recording, the signal is applied to the switch 51 and the frequency discrimination circuit 52.
9 and terminal 50 in the case of conventional recording. Further, in the case of a conventional tape, the signal is output directly to the terminal 50.

According to these embodiments, the recorded content of the tape is determined in the H-VTR, and reproduction is performed in accordance with the determined content. Therefore, the )l-VTR can accommodate five types of recording contents.

On the other hand, since high-band reproduction is not possible with conventional VTRs, it is not possible to reproduce H tapes recorded in high-bands with H-VTRs. However, the other four recorded contents are all conventional recordings and can be reproduced on a conventional VTR.

From the above, this embodiment enables recording and reproduction as shown in FIG. 3, and ensures upward compatibility with conventional VTRs and conventional tapes.

Next, an embodiment of the circuit of the present invention will be described.

FIG. 1 shows a block diagram of a video signal recording system circuit in an embodiment of an H-VTR. In the figure, the chromaticity signal is removed from the NTSCp image signal inputted from the terminal 1 by the chromaticity signal removal circuit 2, and only the luminance signal is applied to the switch 3. The output signal of the above-mentioned tape discrimination circuit is input to the terminal 4 of the switch 3, and the switch 6 is switched in accordance with this signal, and in the case of an H tape, a signal is sent to the switch 5. Switch 5 is a manual switch that can switch between high band recording and conventional recording according to the user's needs.
In the case of high band recording, the signal is the LP for high band recording.
P6. It passes through an FM modulator 7 and is applied to a switch 8.

- If conventional recording is selected with switch 5, the signal is transmitted to LPF 9. 107 FM modulators are applied to switch 8. Also, when a conventional tape is inserted into the H-VTR, the signal is transmitted from switch 3 to LPF 9. sent to the FM modulator 10.

Conventional records are processed. Switch 8 is connected as shown in Figure 1 for high band recording, and reversed for conventional recording.
Send to Fl. In HPFII, signal components in a frequency band overlapping with a low frequency converted chromaticity signal, which will be described later, are removed, and the signal is applied to the 2IOfJ filter 12.

The video signal input from terminal 1 is also applied to the LPF 15, where it becomes only the chromaticity signal component, and the frequency converter 14 converts the subcarrier frequency from 58 MHz to 62 MHz.
9M) Signal components in a frequency band that overlaps the l'M-modulated luminance signal after lz&c low-pass conversion is removed and added to the adder 12.

The luminance signal and the chromaticity signal are frequency-multiplexed by the adder 12, passed through the distribution amplifier 16, and recorded on the magnetic tape 18 via the video head 17.

FIG. 7 shows a block diagram of a video signal reproduction circuit in the embodiment. In the figure, the video signal recorded on the magnetic tape 18 is read out by the video head 17, and is applied to the LPF 40 via the reproducing amplifier 39Y. Here, FM
After that, for example, the recording content is determined by the determination circuit 41 shown in FIG. It will be done.

On the other hand, in the case of conventional recording, the conventional FM equalization circuit 46Y
: Added to the pass switch 44. The switch 44 is a switch that is switched by the output of the frequency discrimination circuit 52, and when the reproduced signal is high band recording, the connection is as shown in FIG.
In the case of conventional recording, the connection is reversed.

The signal is sent from the switch 44 to the FM demodulator 45 , where it is demodulated, and then unnecessary frequency components are removed by the LPF 46 and added to the adder 47 .

The output of the regenerative amplifier 39 is also applied to the LPF 4B, where it becomes only the chromaticity signal with the low frequency range Km converted.The output of the regenerative amplifier 39 is converted to the original 5saMaz subcarrier by the frequency converter 49, and unnecessary frequency components are removed by the LPF 50. is removed and the adder 47
added to. Here, it is frequency multiplexed with the previously mentioned luminance signal to become the original NT8C signal and output to the terminal 51.

By using the circuits shown in Figures 1 and 7 to record the frequency allocation signals shown in Figure 2, it is possible to ensure upward compatibility and to record I/I/I/N signals. becomes.

〔Effect of the invention〕

As described above, the present invention provides a VH8VTR with
Two-band recording7 is performed using a magnetic tape for no-band recording with excellent short-wavelength hole characteristics, and a circuit for discriminating between high-band tape and conventional tape, a recording method selection switch, and a reproduction signal control circuit are also installed. By using a discriminating circuit between the 1-key card and the conventional one, it is possible to ensure upward compatibility in a VTR for recording a blank card, and to realize error-free selection and automatic discrimination of the card for recording.

The tape discrimination @ path and frequency discrimination circuit automate the discrimination between high band and conventional method during playback, and
At the time of recording, high band recording can be arbitrarily selected only when a tape for the )1 band is used, and the inconvenience of erroneously performing high band recording on a conventional tape can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a recording system according to the present invention, and FIG. 2 is an explanatory diagram showing the frequency allocation of a recording signal in the conventional standard of VH 80,000-type VTR and the present invention.
Figure 3 shows magnetic tape and VTR. Explanatory diagram showing reproduction results by combination of recording methods, Part 4
The figure is an explanatory diagram of a tape discrimination device, FIG. 5 is a block diagram of a discrimination circuit during recording, FIG. 6 is a circuit block diagram of a frequency discriminator, and FIG. 7 is a block diagram showing an embodiment of a playback system according to the present invention. It is a diagram. 2...Chromaticity signal removal circuit, ! , 5.8...Switch, 6,9...LPF, 7
．． 10... FM modulator, 21... Tape discrimination device. 26.28.51...Switch, 32...Frequency discriminator, 55, 56...BPF, 37...Level comparator. 41... Recording system discrimination circuit, 42.43... FM equalization circuit. 44...Switch. Representative Patent Attorney Katsuo Ogawa' ＼, 30 Tsumugi 2 Kunima 3n Tsumubr: 3 Tsubo 70

Claims (1)

[Claims] 1. A first recording mode in which a video luminance signal is recorded on a magnetic tape as an FM modulated signal with a carrier frequency, and a video luminance signal is recorded in a carrier frequency higher than that in the first recording mode. A cassette-type magnetic tape that has a second recording mode in which it is recorded on a magnetic tape as an FM modulated signal, and uses a specified magnetic tape with excellent short wavelength recording characteristics when recording in the second recording mode. In the recording/playback device, a cassette half containing a specified magnetic tape used in the second recording mode is provided with a shape characteristic, and a circuit for detecting this characteristic and selecting the first and second recording modes at the time of recording are provided. 1. A magnetic recording and reproducing apparatus comprising a switch and a circuit that determines whether recording is performed in a first or second recording mode based on the frequency of a reproduction signal during reproduction. 2. In the magnetic recording and reproducing apparatus according to claim 1, if the characteristic of the shape of the cassette used in the second recording mode is not detected during recording, the first recording mode is started regardless of the position of the switch. A magnetic recording/playback device characterized in that it records in a mode. 3. In the magnetic recording/playback device according to claim 1, if the characteristic of the shape of the cassette used in the second recording mode is not detected during playback, the first recording mode is started regardless of the position of the switch. A magnetic recording/playback device configured to perform playback signal processing corresponding to the mode. 4. In the magnetic recording and reproducing apparatus according to claim 1, the circuit for determining the frequency of the reproduction signal includes a bandpass filter that passes the luminance FM carrier frequency in the first recording mode, and a bandpass filter that passes the luminance FM carrier frequency in the first recording mode. It consists of a band leaker that passes the luminance FM carrier frequency of , and a circuit that compares the levels of the outputs of both band filters, and is configured to input the reproduced luminance FM modulated signal to both band filters. A magnetic recording/playback device characterized by: