JPH0447386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic recording device, and particularly to a magnetic recording device that records by automatically switching between two modes with different carrier frequencies.

Conventional technology Currently, household tapes using 1/2 width tape are used.
In VTR, the coercive force Hc is approximately 600 [Oe] to 750 [Oe],
An iron oxide magnetic tape (hereinafter referred to as standard magnetic tape) with a residual magnetic flux density Br of approximately 1100 [Gauss] to 1300 [Gauss] is used, and this standard magnetic tape has a magnetic flux density of approximately 3.4MHz.
Recording is performed using a carrier wave frequency set between ~5.5 MHz (for example, 3.4 MHz ~ 4.4 MHz), but in recent years, the performance of magnetic tape and magnetic heads has improved, and high resolution image quality
VTRs are becoming more and more in demand.

Therefore, in place of the standard magnetic tape mentioned above,
Coercive force used in mmVTR, commercial VTR, etc.
Hc is approximately 1300 [Oe] ~ 1500 [Oe], residual magnetic flux density Br
A metal tape with a high coercive force Hc of approximately 2700 [Gauss] to 2800 [Gauss] and a high residual magnetic flux density Br is used. carrier frequency (e.g. 5MHz to 7MHz)
Various types of VTRs have been considered that allow recording by using .

However, if the recording and playback mode in the current 1/2-internet home VCR is set to standard mode, and the recording and playback mode with a higher carrier wave frequency is set to high-quality mode, the carrier wave frequencies of these two modes are significantly different from each other, so Therefore, there is no compatibility between the recorded signals.

Furthermore, existing high-performance magnetic tapes such as the metal tapes used in the 8mm VTRs and commercial VTRs have a coercive force Hc of approximately 1300 [Oe] or more, which is much higher than the standard magnetic tapes mentioned above. When used in the current 1/2-internet home VTR, not only does head saturation occur and the desired characteristics cannot be obtained, but the long wavelength characteristics (linear audio characteristics) and erasure characteristics associated with recording and reproducing audio signals are inferior. It is not suitable for standard mode because it causes various problems such as storage, etc., and can only be used for high-quality mode. On the other hand, standard magnetic tape cannot be used in high-quality mode due to its performance, but can only be used in standard mode.

Therefore, in order to meet the above-mentioned demands, a new high-definition model equipped with a high-definition mode recording and playback means is needed.
It is sufficient to provide a high-performance cassette containing a VTR and the metal tape used in the above 8mm VTR and professional VTR, but in this case, the user will not be able to use the tapes that are compatible with each other.
It requires a VTR and various cassettes, making it very inconvenient to use.

Therefore, while providing a VTR equipped with recording and reproducing means for both the standard mode and high image quality mode and a switch for switching between these two modes, we also offer an 8mm VTR.
A high-performance cassette that stores metal tape used in commercial and professional VTRs has the same shape as the current standard cassette that stores standard magnetic tape, allowing the user to distinguish between the standard cassette and the high-performance cassette and switch to any mode. It is conceivable to perform a switching operation.

Problems to be Solved by the Invention However, in this case, since the cassette cases have substantially the same shape, it is easy to make a mistake in identifying whether a standard cassette containing a standard magnetic tape is a high-performance cassette containing a high-performance magnetic tape. Moreover, it is extremely troublesome to identify each cassette one by one and switch modes. There are problems such as if you make a mistake and record it, you may make a mistake, and when you play it back, it may be mistaken for a malfunction.

In addition, it is quite conceivable that users who own current VCRs may mistakenly purchase and use high-performance cassettes of the same shape, and they may also have the inconvenience of being confused as to which cassette to purchase. isn't it.

The present invention stores a magnetic tape capable of recording in both modes in a high-performance cassette, automatically distinguishes between a standard cassette and a high-performance cassette during recording, and at the same time is equipped with a standard recording mode priority switch, so that the standard cassette can only be used in the standard mode. In a high-performance cassette, a standard recording mode priority switch means is used to select and record between standard mode and high-quality mode, and the standard recording mode priority switch means can be used to change the cassette or switch the power supply. It is an object of the present invention to provide a magnetic recording device which can be reset by turning on and off the magnetic disk, thereby preventing erroneous recording.

Means for Solving the Problems In FIG. 1, the cassette discrimination circuit 13 detects the presence or absence of a cassette discrimination hole in the attached cassette to determine whether a cassette, a standard cassette or a high-performance cassette, is attached to the device. The standard recording mode priority switch 60 (not mechanically locked type) is a priority switch means for giving priority to the standard recording mode, and the inverter 61, AND gate 62, and switch 14 are means for determining whether the cassette is a standard cassette or not. When it is determined that it is a high-performance cassette, it automatically switches to standard recording mode, and when it is determined that it is a high-performance cassette, it automatically switches to high-quality recording mode, and when it is determined that it is a high-performance cassette, it is linked to the operation of the standard recording mode priority switch means. The switch reset pulse generating circuit 31, which is a means for forcibly switching to the standard recording mode regardless of the judgment of the cassette discriminating means, detects the replacement of the cassette or the on/off of the power switch and switches the standard recording mode priority switch. 60 is an example of each of the means for resetting 60.

Function: The high-performance cassette contains a magnetic tape capable of recording in both modes, so it can be used with both current VTRs and this device.When recording, the cassette discrimination circuit 13
The switch 14 can automatically distinguish between a standard cassette and a high-performance cassette and switch to the respective recording mode, and when the cassette is a high-performance cassette, a standard recording mode priority switch 60 can selectively switch between the standard recording mode and the high-quality recording mode. You can also switch to
Set the standard recording mode priority switch 60 to recording mode 1.
Since it is reset every time, erroneous recording can be prevented.

Example Figure 3 shows the standard cassette 1, which is an iron oxide magnetic tape currently used in 1/2-inch home VTRs (coercive force is about 600 [Oe] to 730 [Oe], residual magnetic flux density is about 1100 [Oe]). Gauss] ~ 1300 [Gauss]) are stored. 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.
It has approximately the same shape as , and houses a high-performance magnetic tape, which will be described later. 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.

The high-performance magnetic tape stored in the high-performance cassette 7 has a luminance signal recording wavelength of 1.3 μm.
At 0.97μm and 0.73μm, the playback output value when recording at a current approximately 20% higher than the optimal recording current value of the standard tape used in current 1/2-inch home VTRs is the maximum output of the standard tape. For example, a Co-coated iron oxide magnetic material is used for the magnetic layer and the coercive force is 750 [Oe] so that the erasure rate of the audio signal is better than -65 dB. ] to 950 [Oe], the residual magnetic flux density is at least 1250 Gauss or more, and the grain length of the magnetic layer is at least 0.2 μm or less, or the magnetic layer is made of a metal magnetic material and the coercive force is 700 [Oe]. ] to 850 [Oe], a residual magnetic flux density of 2600 [Gauss] to 2800 [Gauss], and a particle length of the resistant layer of at least 0.16 μm or less. This high-performance magnetic tape is capable of recording in both standard recording mode and high-quality recording mode.

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 provided at a position opposite to the cassette discrimination hole 6a when a high performance cassette 7 is installed. 60
63 is a standard recording mode priority switch, 63 is an input signal changeover switch to be described later, and 32 is a recording mode display device, each of which is provided on the front surface of the panel. The standard recording mode priority switch 60 is of a non-mechanical locking type, and has an electrical latch-up function.
It has a forced L reset mode by reset.

Here, when, for example, the standard cassette 1 is installed in the apparatus shown in FIG. ) is taken out, and the switch 14 is connected to terminal A by the L level output of the AND gate 62 to enter the standard mode. Further, the recording mode display device 32 displays the standard recording mode by the L level output of the AND gate 62. At this time, since the L level signal is being output from the cassette discrimination circuit 13, this display will not change even if the standard recording mode priority switch 60 is operated. On the other hand, when the high-performance cassette 7 is installed in the apparatus shown in FIG. The switch 14 is connected to the terminal B by the H level output of the AND gate 62, and the high image quality mode is set.
Further, the recording mode display device 32 displays the high-quality recording mode by the H level output of the AND gate 62.

However, if the user wishes to record in the standard recording mode even though a high-performance cassette is installed, the standard recording mode priority switch 60 is operated. As a result, an H level signal is taken out from the switch 60, is set to an L level by the inverter 61, and the AND gate 6
2 is set to L level, the switch 14 is connected to terminal A, and the standard mode is set. Further, the recording mode display device 32 displays the standard recording mode by the L level output of the AND gate 62.

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 holder, the holder descends and the cassette identification pin 8 and the cassette identification hole 6a engage with each other. Let's be a guide together,
The engagement between the two is ensured. Furthermore, when a high-performance cassette is installed, the standard mode and high-quality mode can be freely selected by operating the standard recording mode priority switch 60.

By the way, if you operate the standard recording mode priority switch 60 (switch to standard recording mode) after installing a high-performance cassette in order to record in standard mode on a high-performance cassette, standard recording will not be performed even after recording in standard recording mode has finished. The mode priority switch 60 remains in the standard recording mode unless operated again. For this reason, if the high-performance cassette is removed and a new high-performance cassette is installed after the standard mode recording is completed, recording will similarly occur in the standard mode.

In this case, it is generally not often used to record continuously on a high-performance cassette in standard recording mode.
Records in high-quality recording mode on a high-performance cassette,
On very rare occasions, it is recorded on a high-performance cassette in standard recording mode. In such a case, there will be no problem if the user checks the position of the standard recording mode priority switch 60 each time he or she records, but once the user operates the switch, he or she forgets about it, causing problems when recording in the standard recording mode from then on. This is dangerous and extremely inconvenient to use.

Therefore, in the device of the present invention, as shown in FIG.
The cassette replacement detection circuit 28 detects that the cassette has been replaced, or the power switch 2
9 is detected, and this causes OR gate 3 to be turned on.
0 through the switch reset pulse generation circuit 31
A switch reset pulse is generated from the switch, and the standard recording mode priority switch 60 is reset by this. If you do this,
Since both inputs to the AND gate 62 are at the H level, a high-quality recording mode is set, and the above-mentioned inconvenience does not occur, and usability can be improved.

Next, a method of recording using different carrier frequencies according to each mode will be described. 1st
In the figure, when the input video signal to be handled is a composite video signal, the switch 63 is connected to terminal A, and when it is a luminance signal/chroma signal separate video signal, the switch 63 is connected to the terminal port. For example, the composite video signal inputted to the terminal 9 is supplied to a reduction filter and comb filter 10a with a cut-off frequency of, for example, about 3 MHz and a reduction filter and comb-shaped filter 10b with a cut-off frequency of, for example, about 5 MHz, where it is converted into a luminance signal component. and pre-emphasis circuits 11a and 11, respectively.
The high frequency band is enhanced at b, and the FM modulators 12a and 12b
is supplied to The FM modulator 12a performs FM modulation using a carrier frequency of 3.4MHz to 4.4MHz as described later to produce a standard mode FM luminance signal, while the FM modulator 12b uses a carrier frequency of 5.0M.
FM modulation is performed using Hz to 6.7MHz to produce a high-quality mode FM brightness signal, which is sent to the adder 1 via a switch 14 that is switched according to each mode.
5.

The frequency spectrum of the FM luminance signal is as shown in Figure 5 in the standard mode, and as shown in the same figure in the high-quality mode, the carrier frequency is set higher than in the standard mode, and its deviation is also higher than in the standard mode. is also set widely.

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 3.4 MHz, f _AP is 3.8 MHz, f _AW is 4.4 MHz,
The above carrier frequency f _BS in high image quality mode is 5.0MHz,
_fBP is 5.6MHz and _fBW is 6.7MHz.

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 in the other mode. At the time of reproduction in the present invention, mode discrimination is performed with this point in mind.

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 case of separate video signals, the luminance signal input to the terminal 9y and the chroma signal input to the terminal 9c are processed in the same manner as described above.

Further, the recording amplifier 18 may change the characteristics and magnitude of the recording current according to the characteristics of the magnetic tape used, for example, for standard magnetic tape and high performance magnetic tape. It is also possible to provide recording amplifiers each having a desired characteristic and size set according to the characteristics of the recording amplifier, and to switch these amplifiers by the output signal of the AND gate 62.

In the above embodiment, a hole 6a for cassette identification was provided in the insertion prevention recess 6 on the bottom of the cassette to determine the type of cassette. The type of cassette is determined by the provided identification hole.

FIG. 8 shows a standard small cassette 68 in which a standard magnetic tape is stored. FIG. 9 shows a high-performance small cassette 69, which stores a high-performance magnetic tape capable of recording in both standard recording mode and high-quality recording mode, and has an identification hole 65 on the back side. A high performance small cassette is detected by detecting this discrimination hole 65 using a discrimination switch means such as a leaf spring in the apparatus.

In addition, the small cassettes 68 and 69 are of standard type.
When used attached to a VTR, it is housed in an adapter 66 shown in FIG. 10 and attached to the VTR. In this case, when the standard small cassette 68 shown in FIG. 8 is attached to the adapter 66, the identification hole 67 on the back side of the adapter 66 is closed as shown in FIG. 10B, while the high performance small cassette shown in FIG. 69 is attached to the adapter 66, the identification hole 67 on the back surface of the adapter 66 is opened as shown in FIG. 10B. By detecting the opening and closing of the discrimination hole 67, a standard small cassette 68 or a high performance small cassette 69 is discriminated.

In this way, the device of the present invention automatically switches modes as soon as the cassette is installed.
There is no need to carefully identify and judge each cassette and change the mode, and there is no possibility of making an erroneous operation such as setting the high image quality mode for recording even though the cassette is a standard cassette. Furthermore, when a high-performance cassette is installed, by operating the standard recording mode priority switch 60, it is possible to select and record in both modes, which can be effectively used, for example, when it is desired to play back even on a current VTR.

In the above embodiment, the standard recording mode priority switch 60 and the recording mode display device 32 are configured separately, but they may be configured as an integrated unit in which the standard recording mode priority switch 60 has a display function.

Effects of the Invention According to the device of the present invention, it is easy to use because there is no need to perform complicated operations such as carefully identifying each cassette one by one and switching modes during recording. It is possible to prevent accidental operation when recording in this mode, and since the high-performance cassette can record in both modes, it can be used with current VTRs without any problems.
When a high-performance cassette is installed, any mode can be selected by operating the standard recording mode priority switch, which makes it easy to use, and the cassette identification hole is protected by a stepped recess to prevent incorrect insertion. This prevents the intrusion of dust, etc., and when inserting the cassette into the holder of another device, the groove and stepped portion of the recess for preventing erroneous insertion serve as a guide.
The engagement between the two is ensured, and furthermore, the system detects whether the power switch is turned on or off, or when the cassette is replaced, and resets the standard recording mode priority switch.For example, when a high-performance cassette is installed, It has features such as being able to prevent erroneous recording, such as by recording in standard mode and then inserting a new high-performance cassette after recording ends to switch to high-quality recording mode.

[Brief explanation of the drawing]

1 and 2 are respectively a block system 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 the frequency spectrum of the FM luminance signal, Fig. 6 is a luminance signal waveform diagram, Fig. 7 is a perspective view of a small cassette, Figs. 8 and 9 are perspective views of a standard small cassette and a high performance small cassette, respectively.
FIG. 10 is a perspective view of the small cassette adapter. 1, 68... Standard cassette, 6... Recess for preventing incorrect insertion, 6a, 65, 67... Hole for cassette identification, 7, 69... High performance cassette, 8... Pin for cassette identification, 9, 9y, 9c...Video signal input terminal, 10a, 10b...Low pass filter and comb filter, 12a, 12b...FM modulator, 1
3...Cassette discrimination circuit, 14...Switch, 1
9 ₁ , 19 ₂ ... magnetic head, 20 ... magnetic tape, 28 ... cassette replacement detection circuit, 29 ...
Power switch, 30...OR gate, 31...Switch reset pulse generation circuit, 32...Recording mode display device, 60...Standard recording mode priority switch, 61...Inverter, 62...And gate, 63...Input signal Changeover switch, 66...adapter.

Claims (1)

[Claims] 1 A standard cassette containing a standard magnetic tape capable of recording only in a standard recording mode with a predetermined carrier frequency, and a standard recording mode and a magnetic tape set at a carrier wave frequency higher than the carrier wave frequency in the standard recording mode and wider than its deviation. A high-quality magnetic tape with coercive force, residual magnetic flux density, and particle length set to enable recording in both modes is stored in the cassette housing to distinguish it from the standard cassette mentioned above. A high-performance cassette having a cassette discrimination hole, and a magnetic recording device capable of mounting both of these cassettes, detecting the presence or absence of the cassette discrimination hole in the loaded cassette, and distinguishing between the standard cassette and the high-performance cassette. cassette discriminating means for discriminating which of the cassettes is attached to the device;
It has a standard recording mode priority switch means that gives priority to the standard recording mode, and when the cassette discriminating means determines that the cassette is the standard cassette, the standard recording mode is set, and when it is determined that the cassette is the high performance cassette, the high quality recording is set. means for automatically switching to the standard recording mode, and forcibly switching to the standard recording mode regardless of the determination by the cassette discriminating means when the priority switch means is operated when the cassette is determined to be a high performance cassette; A means is provided for detecting replacement of the standard cassette and high-performance cassette or power on/off and resetting the priority switch means, and automatically switching to a recording mode corresponding to each installed cassette, A magnetic recording apparatus characterized in that, when the high-performance cassette is attached, the priority switch means allows the standard recording mode and the high-quality recording mode to be selected for recording.