JPH0514337B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording/reproducing device, and in particular, it records data by automatically switching between two modes with different carrier wave frequencies, and automatically switches between these modes for reproduction. The present invention relates to a magnetic recording/reproducing device as described above.

2. Description of the Related Art In recent years, the performance of magnetic tapes and magnetic heads has improved, and there has been a demand for VTRs with higher resolution and higher image quality. For this reason, for example,
Instead of the standard magnetic tape that uses iron oxide magnetic material used in current home VTRs, we use high-performance magnetic tape that uses metal, vapor deposition, barium ferrite, etc.
Various high-quality modes have been considered in which recording is performed using a carrier wave frequency that is sufficiently higher than the carrier wave frequency of the standard mode used in VTRs.

Problems to be solved by the invention Therefore, the above standard mode and high image quality mode are set to 1.
For use in a VCR, for example, a switch may be provided to switch between the two modes, and the user may arbitrarily switch between the two modes. However, in this case, since the cassette cases have substantially the same shape, it is necessary to carefully identify and judge whether the cassette is a standard cassette containing a standard magnetic tape or a high-performance cassette containing a high-performance magnetic tape, and then performs a mode switching operation. For example, if a standard cassette is set to high quality mode and recorded, the user may make an incorrect operation, which may be mistaken for a malfunction when played back. be.

Also, when recording, high-performance cassettes may also record in standard mode, so when playing back, it is difficult to tell whether the high-quality cassette was recorded in high-quality mode or standard mode just by looking at it. ,
There are problems such as confusion in mode switching operations.
Furthermore, there is a risk that a high-performance cassette recorded in high-quality mode may be played back in standard mode, or a standard cassette recorded in standard mode may be played back in high-quality mode, so the performance of each magnetic tape is fully exploited for playback. There is a problem that it cannot be done.

The present invention provides a magnetic recording system that automatically distinguishes between a standard cassette and a high-performance cassette during recording, and automatically distinguishes in which mode the signal was recorded during playback so that the signal can be played back in an appropriate mode. The purpose is to provide a playback device.

Means for Solving the Problems In FIG. 1, the cassette discrimination circuit 13 detects the identification part provided in the cassette housing to distinguish between standard cassettes containing standard magnetic tapes and high-performance magnetic tapes. a storage body discriminating means (cassette discriminating means) for discriminating which high-performance cassette is installed in the apparatus, and a switch 1;
4 is a means for switching to standard recording mode when using a standard cassette, and switching to high-quality recording mode when using a high-performance cassette, and a mode discrimination circuit 37 determines whether the signal recorded on the magnetic tape is in standard recording mode or high-quality recording mode. The switches 34 and 41, which are playback determination means for determining whether the cassette was recorded in the standard recording mode, switch to the standard playback mode if the cassette is recorded in the standard recording mode, or to the high-definition playback mode if the cassette is recorded in the high-definition recording mode. This is one embodiment of the means for respectively switching to.

Function During recording, cassette discrimination circuit 37 and switch 1
4, the standard cassette and high-performance cassette can be automatically distinguished and switched to the respective recording mode, and during playback,
The mode discrimination circuit 37 and switches 34 and 41 can automatically discriminate in which mode the signal was recorded during recording and switch to the respective playback mode, eliminating the risk of malfunction and improving the performance of each magnetic tape. It can be fully extracted and regenerated.

Example Figure 3 shows the standard cassette 1, which is currently used in home VTRs.
Contains iron oxide magnetic tape used in In the figure, 2a and 2b are shaft holes, 3 is a capstan insertion recess, 4a and 4b are tape drawer member insertion recesses, 5 is a lid, and 6 is a recess for preventing incorrect insertion.

Figure 4 shows high performance cassette 7 and standard cassette 1.
The tape has approximately the same shape as the tape, and stores high-performance magnetic tape such as metal tape. In the figure, reference numeral 6a denotes a cassette identification hole, which is provided in a part of the recess 6 for preventing erroneous insertion.

FIG. 1 is a block system diagram of an embodiment of the apparatus of the present invention, and FIG. 2 is a schematic plan view thereof. In Figure 2,
Reference numeral 8 denotes a cassette discrimination pin, which is configured to move up and down by the action of a spring, for example, and is used at a position opposite to the cassette discrimination hole 6a when a high performance cassette 7 is installed.

When, for example, the standard cassette 1 is installed in the apparatus shown in FIG. 2, the cassette discrimination pin 8 is displaced downward, and as a result, the standard cassette switching signal is taken out from the cassette discrimination circuit 13 shown in FIG. , switch 14 is connected to terminal A to enter the standard mode. On the other hand, when the high-performance cassette 7 is installed in the device shown in FIG.
is returned to its original position, and as a result, a high-performance cassette switching signal is taken out from the cassette discriminating circuit 13 shown in FIG.

In this way, simply loading different types of cassettes into the device automatically switches to the respective mode. In this case, since the cassette identification hole 6a is protected by the stepped portion of the erroneous insertion prevention recess 6, the intrusion of dirt and the like can be prevented as much as possible. Furthermore, when the cassette is inserted into the installed holder, the holder descends and the cassette identification pin 8 and the cassette identification hole 6a engage with each other, but at this time, both the groove and the stepped portion of the erroneous insertion prevention recess 6 are engaged. It acts as a guide and ensures engagement between the two.

Next, a method of recording using different carrier frequencies according to each mode will be described. 1st
In the figure, a video signal input to a terminal 9 is supplied to a low-pass filter and comb filter 10a with a cut-off frequency of, for example, about 3 MHz, and a low-pass filter and comb filter 10b with a cassette-off frequency of, for example, about 5 MHz. The luminance signal components are pre-emphasis circuits 11a and 11b, respectively.
The high frequency signal is amplified at , and then supplied to FM modulators 12a and 12b. As described later, the FM modulator 12a performs FM modulation using a carrier frequency of 3.4 MHz to 4.4 MHz (first carrier frequency) to produce a standard mode FM luminance signal, while the FM modulator 12b
Then, FM modulation is performed using a carrier wave frequency of 5.0 MHz to 6.7 MHz (second carrier wave frequency) to produce an FM brightness signal in high image quality mode, and the signal is sent to an adder via a switch 14 that is switched according to each mode. 1
5.

In the standard mode, the frequency spectrum of the FM luminance signal is as shown by I in FIG. 5, and in the high-quality mode, the carrier frequency is set higher than in the standard mode, as shown in the figure.

In the frequency spectrum of the FM brightness signal shown in FIG. 5, f _AS , f _AP and f _AW are the sync chip level S and pedestal level P of the brightness signal shown in FIG.
and the carrier frequency at the white peak level W, and similarly, in the frequency spectrum, f _BS , f _BP
and f _BW indicate the carrier frequency at the sync chip level S, pedestal level P, and white peak level W of the luminance signal. For example, the above carrier frequency f _AS in standard mode is 3.4MHz, f _AP is 3.8MHz,
f _AW is 4.4MHz, the above carrier wave frequency f _BS in high image quality mode is 5.0MHz, f _BP is 5.6MHz, f _BW is 6.7MHz
It is.

As can be seen from Fig. 5, at carrier frequencies f _AP and f _BP corresponding to the pedestal level, frequency components of the measurement band of the FM luminance signal of the other mode also exist, but at carrier frequencies f _AP and f _BP , The energy is sufficiently larger than the energy of the wave measurement band component of the same frequency as the other mode. At the time of reproduction in the present invention, mode discrimination is performed with attention paid to this point.

On the other hand, the video signal input to the terminal 9 is converted into a chroma signal by the band filter 16, processed by the recording chroma processing circuit 17, and then sent to the adder 15 as an FM signal.
Added to the luminance signal. The output of the adder 15 is amplified by the recording amplifier 18 and sent to the magnetic heads 19 ₁ , 1
9 ₂ and recorded on the magnetic tape 20.

In the above embodiments, the type of cassette is determined by providing a cassette discrimination hole in the cassette, but in the next embodiment, the type of cassette is determined by a bar code.

FIG. 7 shows a standard cassette 21 containing iron oxide magnetic tape. For example, there is a recess 2 on the top surface.
2 is provided, but no barcode, which will be described later, is provided here.

FIG. 8 shows a high-performance cassette 23, which stores high-performance magnetic tape such as metal tape.
A barcode 24 is provided in the recess 22 on the top surface. Also, Figure 9 shows a small high-performance cassette 25.
Similar to the one shown in FIG. 8, a bar code 26 is provided on the top surface. The barcodes 24 and 26 of these high-performance cassettes 23 and 25 are detected by the barcode detection section (optical sensor) 27 shown in FIGS. It is located at a position opposite to.

Here, when the standard cassette 21 is installed, the optical sensor 27 does not operate because there is no bar code here, and as a result, the standard cassette switching signal is taken out from the cassette discrimination circuit 13 shown in FIG. is connected to terminal A and enters standard mode. On the other hand, when the high-performance cassette 23 or 25 is installed, the optical sensor 27 reads the barcode 24 or 26, and as a result, a high-performance cassette switching signal is taken out from the cassette discrimination circuit 13 shown in FIG. Connected to terminal B and enters high image quality mode.

In this case, as in the previous embodiment, simply by loading different types of cassettes into the apparatus, the mode can be automatically switched to the respective mode.

In this way, the device of the present invention automatically switches modes simply by attaching a cassette, so there is no need to carefully identify each cassette and switch modes. However, if you set it to high quality mode and record, you won't make any mistakes.

Next, the operation during playback will be explained.

In the figure, FM recorded on magnetic tape 20
The frequency-division multiplexed signal of the luminance signal and the low-frequency conversion carrier chrominance signal is alternately reproduced by the magnetic heads 19 ₁ and 19 ₂ and is passed through the preamplifiers 28 ₁ and 28 ₂ by a head switching pulse of 2 field periods from the terminal 30. Switch being switched 2
9, where it is converted into a continuous signal and then supplied to a high-pass filter 31 and a low-pass filter 32.
Playback FM separated by high-pass filter 31
The brightness signal is equalized by the equalizer circuit 33 in high image quality mode.
a and the standard mode equalizer circuit 33b separately to the switch 34, and from this
The signal is supplied via the AGC circuit 35 to a limiter 36 and a mode discrimination circuit 37, respectively.

The reproduced FM luminance signal from which amplitude fluctuation components have been removed by the limiter 36 is supplied to the switch 41 via the FM demodulator 38a, low-pass filter 39a, and de-emphasis circuit 40a of the standard mode reproduction system, while the FM demodulator 38
b, is supplied to the switch 41 via the low-pass filter 39b and the de-emphasis circuit 40b.

On the other hand, the mode discrimination circuit 37 automatically discriminates whether the reproduced FM luminance signal was recorded in the standard mode or the high-quality mode as described later, and a mode discrimination signal obtained by this is supplied to the system controller 42. Furthermore, this signal is supplied to switches 34 and 41 as a switching pulse.
As a result, the switches 34 and 41 are connected to the terminal A side when the standard mode is determined, and are switched to the terminal B side when the high image quality mode is determined.

Further, the reproduced signal taken out from the switch 29 is separated into a low frequency converted carrier color signal by a low frequency filter 32, and then sent to the reproduced chroma processing circuit 4.
3, jitter is removed by known means and the reproduced carrier color signal of the original band is restored. The adder circuit 44 uses this reproduced carrier color signal and the switch 41
The reproduced luminance signal extracted from the above and reproduced and demodulated by the reproduction system in the same mode as that at the time of recording is added and synthesized and outputted to the output terminal 45 as a reproduced color video signal.

Next, the operation of the mode discrimination circuit 37 will be explained.

FIG. 12A shows a concrete block system diagram of one embodiment of the mode discrimination circuit 37, and FIG. 13 shows its detailed circuit diagram. The reproduced FM luminance signal input to terminal 46 has a pass band at the standard mode frequency f _AP (Figure 5).
A band filter 47a set nearby produces a narrow band signal, while a band filter 47b whose pass band is set near the frequency f _BP (FIG. 5) of the high image quality mode produces a narrow band signal. These narrowband signals are detected by detection and peak hold circuits 48a and 48b.
The peak is held at
Unnecessary frequency components are removed in 9a and 49b.
Considered to be a DC signal. This low-pass filter 49a, 4
Passing through 9b prevents malfunctions in FM signal missing portions due to noise bars and the like during search and stilling.

The output DC signals of the low-pass filters 49a and 49b are supplied to a comparator signal 50, where their levels are compared, and the above-mentioned mode discrimination signal corresponding to each mode is taken out from the output terminal 51 and sent to the above-mentioned system controller shown in the first figure. 42.

FIG. 12B shows a concrete block diagram of another embodiment of the mode discrimination circuit 37. In this device, the output level of the low-pass filter 49 is compared with a reference voltage V _Ref by a comparator 52, thereby outputting a mode discrimination signal corresponding to each mode.

In addition, the output DC of the low-pass filters 49a and 49b
If both signal levels are approximately the same and the level is not stable due to noise etc., comparator 5
Since an output signal of 0 causes so-called chattering, the comparator 50 may be provided with a hysteresis characteristic to prevent this chattering.

Moreover, peak hold circuits 48a, 48b, 48
The longer the time constant is, the less the peak hold will be affected by the video interval, but on the other hand, if the amplitude of the extracted FM signal changes greatly due to noise etc., and the outputs of the comparators 50 and 52 are inverted. takes a long time to recover. Therefore, the time constant is selected to be an optimal value that is not affected by the video section and that shortens the return time.

In this manner, the apparatus of the present invention automatically determines in which mode the signal was recorded simply by reproducing the cassette, and switches to the appropriate mode. Here, a high-performance cassette 7 is recorded using a conventional magnetic recording/reproducing device.
(Figure 4) or 23 (Figure 8), 25 (Figure 9)
When playing back what was recorded in standard mode,
Simply attach these high performance cassettes 7 and 2 to the device of the present invention.
3, 25 and detects the cassette identification hole 6a or the barcode 24, 26 to determine that it is a high performance cassette 7, 23, 25 and set the high image quality mode, playback in the standard mode will not work. It doesn't mean you've dealt with it. However, since the device of the present invention is configured to play back the cassette and switch to that mode, if a high-performance cassette recorded in standard mode is loaded using a conventional device, it will not switch to high-quality mode. Switches to standard mode correctly.

In the apparatus of the present invention, during playback, the signal is supplied to the output system controller 42 of the cassette discrimination circuit 13 to switch the switches 34 and 41 to their respective modes. As a result, when playing back what was recorded in high quality mode on the high performance cassettes 7, 23, 25,
If you want to play back something that was recorded in standard mode,
Mode switching can be performed more reliably. in this case,
For example, when a conventional device records a high-performance cassette in standard mode and plays it back with the device of the present invention, the device is first set to high-quality mode, but the playback signal immediately switches to standard mode, so there is no problem. No problem.

Further, during reproduction, the output of the cassette discriminating circuit 13 may not be supplied to the system controller 42, and mode switching may be performed only by the reproduction signal.

In addition, as mentioned above, if you want to record in standard mode for use with a conventional device, a standard mode priority switch is provided in addition to switch 14 in Fig. 1, and this switch is operated during recording. You may also do so.

Effects of the Invention According to the device of the present invention, when recording, the type of storage object can be determined by detecting the identification part provided on the storage object (cassette), so that the operator can carefully identify each cassette one by one. It is easy to use because there is no need to perform complicated operations such as identifying and switching modes. For example, it is possible to select the optimal recording mode according to the characteristics of the recording medium (magnetic tape) and automatically switch. This prevents erroneous operations such as recording in high quality mode on a standard cassette, and since the cassette identification hole is protected by the stepped part of the recess for preventing erroneous insertion, there is no possibility of dust etc. In addition, when inserting a cassette into a holder for another device, the groove and stepped portion of the recess for preventing erroneous insertion serve as guides to ensure the engagement of the two. Sometimes, the recording mode at the time of recording is determined based on the reproduction signal reproduced from the recording medium without detecting the identification section provided on the storage body, and the reproduction mode is automatically switched to the reproduction mode corresponding to the recording mode. Therefore, there is no need to worry about mode switching operations, and it is easy to use.For example, when playing back a high-performance recording medium (high-performance magnetic tape) installed in a high-performance storage body (high-performance cassette) that was recorded in the standard mode. It has features such as being able to reliably play back in the standard playback mode in some cases, and preventing erroneous operations such as when playing back a high-performance cassette recorded in the high-quality mode in the standard mode.

[Brief explanation of the drawing]

1 and 2 are respectively a block diagram and a schematic plan view of an embodiment of the apparatus of the present invention, FIG. 3 is a perspective view of a standard cassette, FIG. 4 is a perspective view of a high performance cassette, and FIG. 5 is a perspective view of a high performance cassette. is the frequency spectrum of the FM luminance signal, Fig. 6 is the luminance signal waveform diagram, Fig. 7 is a plan view of the standard cassette, Figs. 8 and 9 are plan views of the high performance cassette, and Fig. 10 is the cassette installed in the device. Figure 11 is a diagram showing the position of the optical sensor and the barcode on the cassette, Figure 12 and Figure 1 are for insertion.
3 is a concrete block diagram of the mode discrimination circuit shown in FIG. 1 and a concrete circuit diagram thereof, respectively. 1, 21... Standard cassette, 6... Recess for preventing incorrect insertion, 6a... Hole for cassette identification, 7, 23,
25... High performance cassette, 8... Cassette identification pin, 9... Video signal input terminal, 10a, 10b
...low-pass filter and comb filter, 12a,
12b...FM modulator, 13...Cassette discrimination circuit, 14, 34, 41...Switch, 24, 26
... Barcode, 27 ... Barcode detection section (light sensor), 35 ... AGC circuit, 37 ... Mode discrimination circuit, 38a, 38b ... FM demodulator, 42 ...
...System controller, 45...Output terminal, 4
7a, 47b, 47...Band filter, 48a,
48b, 48...detection and peak hold circuit,
49a, 49b, 49...low-pass filter, 50,
52...Comparator.

Claims (1)

[Claims] 1. In a magnetic recording and reproducing device that records and reproduces an input signal via a recording medium provided in a storage body, a standard recording medium is stored by detecting an identification section provided in the storage body. storage object discrimination means for determining whether either a standard storage medium containing a high-performance recording medium or a high-performance storage medium containing a high-performance recording medium is installed in the device; , a recording means for selecting a high-performance recording mode when determining the high-performance storage body; and a recording means that selects a high-performance recording mode when the recording medium is in the standard recording mode or the high-performance recording mode based on a reproduction signal reproduced from the recording medium. reproduction determination means for determining whether the reproduction signal is recorded in the standard recording mode; and when determining that the reproduction signal is recorded in the standard recording mode, the reproduction signal is recorded in the standard reproduction mode, and the reproduction signal is recorded in the high performance recording mode. 1. A magnetic recording and reproducing device characterized by comprising means for switching to a high performance reproducing mode when it is determined that the mode is the same. 2. In a magnetic recording and reproducing device that records and reproduces input signals via a magnetic tape provided in a cassette, it is possible to distinguish between a standard cassette containing a standard magnetic tape and a high-performance magnetic tape by detecting an identification section provided in the cassette. a high-performance cassette containing a cassette, and a cassette discriminating means for discriminating whether any of the high-performance cassettes containing a a recording means for selecting a high-performance recording mode set to a higher carrier frequency than the high-performance recording mode; a reproduction determination means for determining whether the reproduction signal was recorded in the recording mode; and when it is determined that the reproduction signal is recorded in the standard recording mode, the reproduction signal is recorded in the standard reproduction mode and the reproduction signal is recorded in the high performance recording mode. 1. A magnetic recording and reproducing apparatus, comprising: means for switching to a high performance reproduction mode when it is determined that 3 Playing back a magnetic tape recorded in a standard recording mode in which FM modulation is performed and recorded at a first carrier frequency or in a high performance recording mode in which FM modulation and recording is performed at a second carrier frequency higher than the first carrier frequency. A magnetic recording/reproducing device, wherein the magnetic tape is in the standard recording mode or a reproduction determination means for determining whether the reproduction signal was recorded in the high-performance recording mode; and when it is determined that the reproduction signal is recorded in the standard recording mode, the reproduction signal is switched to the standard reproduction mode; 1. A magnetic recording and reproducing apparatus comprising means for switching to a high performance reproduction mode when it is determined that recording is being performed.