JPS6188678A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain reproduction surely in response to characteristics by using a frequency of a synchronizing signal in an FM luminance signal recorded at each recording standard to discriminate the standards of recording thereby switching automatically the characteristics of a reproducing signal processing system and omitting the operation for each recording standard. CONSTITUTION:A reproducing video signal (a) is fed to a filter 24 set so that a synchronizing signal subjected to FM modulation in the video signal of a recording standard passes through from an input terminal 21, a synchronizing signal (b) is separated and rectified by a rectifier circuit 25. Portions other than the synchronizing signal portion are excluded by using the same frequency as the synchronizing signal (b) to supply the synchronizing signal (d) from an input terminal 22 to a gate 26 as a gate pulse thereby driving an FF27. A head switching signal (f) is applied to a reset pulse generating circuit 28 from an input terminal 23 to reset the FF27 at each field. The output level of the FF27 is changed depending on the presence of the signal from the gate 26.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention reproduces images with higher quality than conventional ones.

The present invention relates to a magnetic recording and reproducing device that is capable of selectively recording and reproducing according to a recording standard different from the current one.

[Background of the invention]

In conventional magnetic recording and reproducing devices (hereinafter referred to as VTR) such as the VH8 system, when recording video signals of the current standard system (for example, NTSC system and below, simply referred to as the standard system), the brightness The signal is FM modulated and the carrier color signal is converted into a low frequency signal, and the FM modulated luminance signal (hereinafter referred to as FM/luminance signal) and the low frequency converted carrier color body array (hereinafter referred to as low frequency converted carrier color) are combined. In this case, as shown in Figure 6, the frequency band FY of the FM luminance signal is shifted to the high frequency side, and the frequency band FY of the FM brightness signal is frequency-multiplexed and recorded on the magnetic tape. Color signal frequency band Fo
is set to the low range side. .

FIG. 7 is a block diagram showing the reproduction signal processing system of such a VTR, in which 1 is a magnetic head, 2 is a preamplifier, 3 is an HPF (bypass filter), 4 is a peaking circuit, and 5 is a block diagram showing a reproduction signal processing system of such a VTR.
is an equalizer, 6 is an FM demodulation circuit, 7 is a de-emphasis circuit, 8 is an equalizer, 9 is a dynamic de-emphasis circuit, 10 is an LPF (low-pass filter),
11 is a color signal processing circuit, 12 is a mixing circuit, and 13 is an output terminal.

As shown in FIG. 6, the frequency-multiplexed FM luminance signal and low frequency conversion carrier color signal are reproduced by the magnetic hector 1, amplified by the preamplifier 2, and sent to the HPF 5 and L P
Flo. FM luminance signal in HPF5, and also in LPFlo.

The low-pass conversion carrier color signals are separated, respectively.

The FM luminance signal separated by the HPF 5 is supplied to the peaking circuit 4 having the characteristic α shown in FIG.
The component near j is emphasized, and then the phase lag characteristic α shown in FIG. 5 is obtained.

After the signal is supplied to the equalizer 5 and the delay characteristics around the frequency F1 are adjusted, it is supplied to the FM demodulation circuit 6.

and demodulated. The demodulated luminance signal is 1.
"It is supplied to the de-emphasis circuit 7 having the characteristic α shown in FIG.
After being supplied to an equalizer 8 having a phase delay characteristic α shown in the figure and adjusting the delay characteristic near the frequency equation 1, it is further processed by a dynamic de-emphasis circuit 9 to form a mixing circuit.

12.

On the other hand, the low frequency conversion carrier color signal separated by LPFlo is supplied to the color signal processing circuit 11, where it undergoes processing such as frequency replacement and crosstalk removal.

A carrier color signal in five frequency bands is obtained from the dark color signal processing circuit 11, and this carrier color signal is mixed with a luminance signal from the dynamic de-emphasis circuit 9 in a mixing circuit 12. Then, the original standard video signal is obtained at the output terminal 15. .

By the way, in recent years, the current standard recording standards (for example.

For example, VH8 standard), high resolution and high S/N can be obtained [
High image quality (hereinafter abbreviated as HQ).

VTR is attracting attention, Kakaru n Q -V TR
,,.

The production was also recorded according to the VH8 standard.

There is a need to make it reproducible. Video belief.

In order to record and play back issues with high image quality on a VTR.

To prevent the characteristics of this video signal from being impaired.

For this purpose, it is necessary to record and reproduce video signals in accordance with a new standard different from the VH8 standard. The standard for recording and reproducing (hereinafter referred to as the recording standard) is to record by frequency multiplexing the FM luminance signal and the low frequency conversion carrier color signal, as in the case of the VH8 standard.

However, because the frequency band of the luminance signal is very wide,
As shown in FIG. 12, the carrier frequency 7'82 of the FM luminance signal is changed to the carrier frequency f8 of the F'M luminance signal in the standard system. It is necessary to make the frequency band F'Y of this FM luminance signal sufficiently wide compared to (FIG. 6).

Thus, the carrier frequency of the FM luminance signal.

fs2 and frequency band p; are FM in VH8 standard
``If the brightness signal is made different from that of the VH8 standard, not only the characteristics of each circuit in the recording signal processing system but also the characteristics of each circuit in the reproduction signal processing system must be made different from those in the VH8 standard.

That is, in the case of the reproduced signal processing system shown in FIG. 7, the peaking circuit 4 processes components near the frequency fP2, which is higher than the frequency J'PI, as shown in FIG.

As shown in FIG. 9, the equalizer 5 needs to have a characteristic that adjusts the delay characteristic near the frequency f□2, which is higher than the frequency f□1. Dien.

As shown in FIG. 10, the fascis circuit 7 must have a characteristic such that higher components are attenuated than in the case of the VHS standard, and the equalizer 8 must have a characteristic that reduces frequency components as shown in FIG. It is necessary to have a frequency formula higher than f'r+, and to have characteristics such that phase adjustment is performed near the dynamic de-emphasis circuit 9.
It is also necessary to make the characteristics of the four-color signal processing circuit 11 different from those of the standard system.

Therefore, it is possible to record and re-record any video signal with different recording standards, VH8 standard and FiQ standard, on a VTR.

In order to make this possible, it is necessary to switch the characteristics of each circuit in the recording signal processing system and the reproduction signal processing system to suit the respective recording standards.

By the way, for example, JP-A-50-87726, JP-A-50-87727, JP-A-57-14710
As disclosed in Japanese Patent No. 4, a technique for switching the characteristics of a circuit in a signal processing system is already known. In this conventional technology, when magnetic tapes with different performances are used, it is possible to obtain good recording and reproducing characteristics for each magnetic tape, and the circuit is manually adjusted depending on the magnetic tape used. I am trying to switch the characteristics of.

Therefore, by applying this technique, in the reproduced signal processing system shown in FIG.
, de-emphasis circuit 7, equalizer circuit 8, dynamic de-emphasis circuit 9 and color signal processing circuit 1
1 when playing back from a magnetic tape recorded in the conventional VH8 recording standard and in the VHS recording standard such as the HQ standard.
It is conceivable to switch the characteristics when playing back from a magnetic tape recorded in a different recording standard (referred to as the new recording standard), but such switching of characteristics is done manually. , it takes a lot of effort and impairs the operability of the VTR, and also causes important problems as described below.

In other words, whether it is a video signal based on the VH8 standard or a video signal based on the new recording standard, once the video signal is recorded on a magnetic tape, it is difficult to determine what recording standard the recorded video signal is based on. You can't tell just by watching the tape. Of course, if video signals and signals of the same type of recording standard are recorded on one magnetic tape, it will be easier to switch the characteristics of the reproduction signal processing system by displaying the recording and standards on the magnetic tape.
This is for the user.

You cannot force people to record in a certain way. .

Therefore, the user has no choice but to attach the magnetic tape to a VTR, play it back, look at the reproduced image, judge which recording standard it is, and then switch the characteristics, but it is not up to the general user to make such a judgment. is almost impossible.

For this reason, even if a VTR is equipped with a characteristic switching means for the playback signal processing system, it cannot be used effectively, and even if video signals of different systems can be recorded and played back using different recording standards, this function cannot be used effectively. The problem is that it cannot be put to good use.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned problems and to enable video signals recorded in different recording standards to be processed without losing their characteristics and requiring special operations for each recording standard. An object of the present invention is to provide a magnetic recording/reproducing device that can perform playback without any problems.

[Summary of the invention]

In order to achieve this object, the present invention focuses on the fact that the frequency of the synchronizing signal in the FM luminance signal recorded for each recording standard is different, and by determining the recording standard based on the frequency of the synchronizing signal, the reproduced signal is The feature is that the characteristics of the processing system are automatically switched for each recording standard.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus according to the present invention, in which 14 is a peaking circuit, 15 is an equalizer, 16 is a de-emphasis circuit, 17 is an equalizer, 1B is a dynamic de-emphasis circuit, 1
9 is a color signal processing circuit, 20 is a determination circuit, and parts corresponding to those in FIG. 7 are given the same reference numerals, and a portion of the explanation will be omitted.

In FIG. 1, this embodiment is shown in FIG.

The prior art described above basically has the same circuit configuration, but includes a discrimination circuit 20, a peaking circuit, an equalizer 15, and a diene.

The difference is that the characteristics of the fascis circuit 16, the equalizer 17, and the dynamic de-emphasis circuit 18 are switchable, and the characteristics of the carrier color signal processing circuit 19 are also switchable.

Next, the operation of this embodiment will be explained using recording and reproduction of a VH8 standard video signal and a HQ standard video signal as examples.

As described above, since the frequency band and carrier frequency of the reproduced FM luminance signal differ between video signals of different recording standards, the frequency of the synchronization signal in the FM luminance signal also differs.

Therefore, the reproduced video signal output from the preamplifier 2 is also supplied to the discrimination circuit 20. The discrimination circuit 20 discriminates the frequency of the synchronizing signal from the supplied reproduced video signal, and outputs a control signal according to the standard of the reproduced video signal. This control signal is supplied to the peaking circuit 14, equalizer 15, de-emphasis circuit 16, equalizer 17, dynamic de-emphasis circuit 18, and color signal processing circuit 19, and the characteristics of these circuits are determined according to the recording standard of the reproduced video signal. is set to

Now, if a video signal according to the VH8 standard is being reproduced from the magnetic head 1, the discrimination circuit 2° discriminates this,
The peaking circuit 14, equalizer 15, de-emphasis circuit 16, and equalizer 17 are set to the characteristics shown by the curves α in FIGS. 8, 9, 10, and 11, respectively, and the video signal according to the new recording standard is reproduced. When the curves in the respective drawings are set to the characteristics already shown.

FIG. 2 is a block diagram showing a specific example of the discrimination circuit 20 shown in FIG. 1 is a reset pulse generating circuit, and 29 is an output terminal.

Figures 5 and 4 show the signals of each part in Figure 2.

2 is a waveform diagram showing signals corresponding to FIG. 2.

have the same sign, and Q represents the video signal.

Furthermore, A and B represent playback periods of video signals according to different recording standards. In addition, Fig. 5.

The time axis is different from that of Figure 4.

In Figures 2, 5 and 4, Buri.

The reproduced video signal α output from the amplifier 2 (Fig. 1) is
The signal is supplied from the input terminal 21 to the filter 24 . The filter 24 is, for example, a BPF (band pass filter) (it may be a low pass filter or a bypass filter), and separates the synchronization signal from the reproduced video signal α. In this case, the passband of the filter 240 is set so that the FM-modulated synchronization signal in the video signal of one recording standard passes. For this purpose, the passband of this filter 24 is set to V
If the FM-modulated synchronization signal in the video signal according to the H8 standard is allowed to pass through, the video signal according to the new recording standard has different recording standards, so the FM-modulated synchronization signal passes through the filter 24. Don't pass.

The output signal of the filter 24 is sent to a rectifier circuit 25.

After being rectified, it is supplied to the gate 26. centre.

Since the filter 24 separates the frequency of the FM-modulated synchronization signal h1, this synchronization signal.

Component b2 having the same frequency is also extracted from other parts than the synchronization signal part. For this purpose, from the input terminal 22.

Supplying the synchronizing signal d as a gate pulse to the gate 26,
Only the synchronizing signal portion C1 is extracted from the output signal C of the rectifier circuit 25. Signal e from gate 26 triggers flip-flop 27. Further, a head switching signal f is supplied from the input terminal 25 to the reset pulse generating circuit 2, and a reset pulse t is formed and supplied to the F+) L/flop circuit 27. Therefore, the flip-flop circuit 27 is reset for each field.

Therefore, if a video signal according to the VH8 standard is being reproduced now, the output signal e from the gate 26 is obtained in the synchronization signal section, and every K after reset by the reset pulse t from the reset pulse generation circuit 28, the flip-flop Tsubu circuit 27 is Sera.

The output signal source is supplied from the output terminal 29 to each circuit shown in FIG. Further, when a video signal according to the new recording standard is being reproduced, since no signal is obtained from the gate 26, the flip-flop circuit 27 is supplied from the reset pulse generation circuit 28.

The reset/sorted state is maintained by the glue set pulse t. For this reason, the level of the output signal I of the 7-lip-flop circuit 27 is different from that when the video signal is reproduced according to the VH8 standard.

In this way, the recording standard of the playback video signal is automatically set.
Moreover, the determination is made accurately, and the characteristics of each reproduction signal processing circuit are automatically switched accordingly. Therefore, operations for each recording standard are not required, and the characteristics of the reproduced signal processing system are reliably switched, so that the characteristics of the reproduced video signal will not deteriorate for any recording standard. .

FIG. 5 is a block diagram showing another embodiment of the magnetic recording/reproducing apparatus according to the present invention. , 502 is a luminance signal processing circuit, 51. , 512 is a color signal processing circuit, 52
, 55 is a changeover switch, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In this embodiment, the characteristics of the reproduced signal processing system are varied by using different luminance signal processing circuits and color signal processing circuits for each recording standard.

In FIG. 5, a luminance signal processing circuit 501 and a color signal processing circuit 51. has characteristics suitable for processing the FM luminance signal and low-frequency conversion carrier color signal of the reproduced video signal according to one recording standard, that is, the video signal according to the VH8 standard, and also has a luminance signal processing circuit. The color signal processing circuit 502 and the color signal processing circuit 512 have characteristics suitable for respectively processing the FM luminance signal and the low frequency conversion carrier color signal of the reproduced video signal according to the new recording standard. Note that the luminance signal processing circuit 50. .

502 consists of each circuit from the peaking circuit 4 to the dynamic de-emphasis circuit 9 shown in FIG.

The luminance signal processing circuit 501 has the characteristics a shown in FIGS. 8 to 11, and the luminance signal processing circuit 502 has the characteristics a shown in FIGS.

Each has the characteristics shown in FIGS. 8 to 11.

The luminance signal processing circuits 501.502 are selected by the changeover switch 52, and the chrominance signal processing circuits 51.502 are selected by the changeover switch 52. , 512 are selected by the switch 53. Also, the changeover switches 52, 5! l is controlled by the output signal of the discrimination circuit 20.

Next, the operation of this embodiment will be explained.

Assuming that the magnetic head 1 is reproducing a video signal according to the VH8 standard, the discrimination circuit 20 discriminates this as described above, and the changeover switches 52 and 55 are controlled by the output signal of this discrimination circuit 20. The luminance signal processing circuit 50. and a color signal processing circuit 51. is selected. Therefore, the FM luminance signal of the video signal according to the VH8 standard is processed by the luminance signal processing circuit 501, and the low frequency conversion carrier color signal is processed by the color signal processing circuit 51. are processed by VH at the output terminal 15.
Video signals of 8 standards can be obtained.

Further, when the magnetic head 1 reproduces a video signal based on the new recording standard, the luminance signal processing circuit 502 and the color signal processing circuit 512 are selected in the same way, and the H signal is output to the output terminal 15.
A Q-standard video signal can be obtained.

In this way, effects similar to those of the embodiment shown in FIG. 1 can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited only to these embodiments.

That is, as in the above embodiment, the video signal may not only be a video signal of the VH8 standard, HQ, or the standard, but also any video signal that is recorded and reproduced with different recording standards such as different horizontal synchronization signals, and By providing two or more discrimination circuits, the present invention can be applied to video signals based on 5 or more recording standards.The present invention is also applicable not only to the NTSC system but also to other systems such as the PAL system. In addition, it is also applicable to VTRs that record and reproduce high-definition television signals.

〔Effect of the invention〕

As explained above, according to the present invention, the recording standard is automatically and reliably determined8, and by this determination,
Since the characteristics of the reproduction signal processing system are set for each recording standard, operations for each recording standard can be omitted, and a reproduced video signal with characteristics according to the recording standard can be reliably obtained. It is possible to provide a magnetic recording and reproducing device that has excellent operability and can fully utilize its multifunctionality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the magnetic recording/reproducing apparatus according to the present invention, FIG. 2 is a block diagram showing a specific example of the determination circuit of FIG. 1, and FIGS. FIG. 5 is a block diagram showing another embodiment of the magnetic recording/reproducing apparatus according to the present invention, and FIG. 6 is a waveform diagram showing signals of each part in the figure.
7 is a block diagram showing an example of a conventional magnetic recording/reproducing device, FIG. 8 is a characteristic diagram showing the characteristics necessary for the peaking circuit shown in FIG. 7, and FIG. The characteristics required for an equalizer for the frequency modulated luminance signal in the figure are shown. The characteristic diagram, Figure 10, is the de-emphasis stage of Figure 7. Fig. 11 is a characteristic diagram showing the characteristics necessary for the equalizer for the frequency demodulated luminance signal in Fig. 7, and Fig. 12 shows the recording standard for the HQ video signal. FIG. DESCRIPTION OF SYMBOLS 1...Magnetic head, 5...Bypass filter, 6 degrees,..., FM recovery 111 circuit, 1o...Low pass filter, 12...Mixing circuit, 15...Output terminal, 14...
・Peaking circuit, 15... Equalizer, 16...
De-emphasis circuit, 17... Equalizer, 18.
... Dynamizuku day emphasis circuit, 19... Color signal processing circuit, 20... Discrimination circuit, 24... Filter, 25... Rectifier circuit, 26... Gate, 27...
・Flip-frosive circuit, 28... Reset pulse generation circuit, ``+ + 502... Luminance signal processing circuit, 511, 512... Color signal processing circuit, 52, 55.
...Switching diagram 3 Figure 4; Figure 11G, Rei frequency table f82 Frequency emission

Claims (3)

[Claims] (1) A magnetic recording and reproducing apparatus that records and reproduces multiple types of video signals of different recording standards in such a manner that at least the frequency modulation carrier frequency of the luminance signal of the video signal is different for each recording standard. A discrimination circuit is provided which detects the frequency of the synchronization signal of the frequency modulated luminance signal and discriminates the recording standard of the reproduced video signal, and the output signal of the discrimination circuit determines the recording standard of the reproduced video signal. 1. A magnetic recording/reproducing apparatus characterized in that the characteristics of a reproduction signal processing system can be switched to suit the needs of the user. (2) In claim (1), the discrimination circuit includes a filter that separates a signal component of a frequency set for a synchronization signal from the reproduced frequency-modulated luminance signal of a predetermined recording standard; A rectifier circuit that rectifies the signal component, a gate circuit that extracts a period portion of the synchronization signal from the output signal of the rectifier circuit, and a flip-flop circuit that is set and periodically reset by the output signal of the gate circuit. A magnetic recording/reproducing device characterized by: (3) In claim (1) or (2), the reproduction signal processing system includes a plurality of reproduction signal processing circuits, each having characteristics according to a different recording standard, and the discrimination circuit. 1. A magnetic recording and reproducing apparatus comprising a changeover switch that selects one of the reproduction signal processing circuits according to an output signal of the reproduction signal processing circuit.