KR100216881B1 - Magnetic recording and reproducing device with selective line noise canceller - Google Patents

Abstract

The magnetic recording and reproducing apparatus includes a reproducing level detector for detecting the level of the reproduced signal and a memory for storing the reproducing level detected by the detector, which is stored and reproduced in advance in this signal when the video signal is recorded. The reproduced level is stored in the memory, and thus the amount of detail emphasis in the reproduction system and the equalization amount of the FM equalizer in the recorder can be controlled according to the stored reproduction level, while the reproduced FM is reproduced when the video signal is reproduced. The level of the luminance signal is detected by the reproduced level detector, and accordingly, the equalization amount of the FM equalizer, the amount of cancellation of the line noise canceller, and the amount of cancellation of the noise canceller in the reproduction system can be controlled according to the detected reproduction level, respectively. .

Description

Magnetic recording and reproducing apparatus with an optional line noise canceller.

1 is a block diagram schematically showing the main parts of a recording and reproducing system of a home VTR of a first embodiment according to the present invention;

FIG. 2 is a block diagram showing details of main parts of the recording system and the reproduction system of FIG.

3 is a block diagram schematically showing the main parts of a recording system and a reproduction system of a conventional home VTR.

FIG. 4 is a block diagram showing line noise canceling in the FIG. 3 recorder and reproduction system. FIG.

5 is a characteristic diagram showing a reproduction output level of a normal tape and a high sensitivity tape.

6 is a characteristic diagram showing playback video levels of normal tape and high sensitivity tape.

7 and 8 are characteristic diagrams showing line ozone cancellation.

8 is a spectrum of a signal reproduced by a video head of a signal magnetized on a video tape in a VTR.

10 is a characteristic diagram of the recorder FM equalizer of FIG.

11 is a characteristic diagram of the reproduction system FM equalizer of FIG.

12 is a characteristic diagram of a peaking circuit of the regeneration system shown in FIG.

FIG. 13 is a block diagram showing a detail emphasis circuit in the recorder reproduction system of FIG.

14 is an explanatory diagram showing a signal level according to a conventional example.

15 is an explanatory diagram showing a signal level according to an embodiment of the present invention.

FIG. 16 is a block diagram showing a second embodiment of the present invention. FIG.

17 is a block diagram showing a third embodiment of the present invention.

18 is a block diagram showing a fourth embodiment of the present invention.

19 is an explanatory diagram showing an application example of the fourth embodiment of the present invention.

20 is an explanatory diagram showing a fifth embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording and reproducing apparatus, for example, a home VTR, in which a luminance signal of a video signal to be recorded is FM modulated and recorded on one side wave.

In general household VTR, record Since the frequency band of the signal to be reproduced and obtained is narrower than the frequency band of the FM modulated luminance signal of the video signal for recording, the high band of the upper band of this FM signal is recorded. It does not play. As a result, the FM signal becomes a single sideband FM signal, and thus the reproduced FM signal is accompanied by an amplitude variation. When the amplitude fluctuation is removed by the limiter and demodulated, the high frequency portion of the upper band wave described above is restored. This is a one-sided wave record.

However, the FM signal passing through the limiter has a low modulation level because the high frequency portion of the restored high frequency wave and the low frequency portion of the low frequency wave are low. When the FM signal is demodulated, the high frequency of the demodulation luminance signal is smaller in energy than the region, so the level of the signal is reduced. In order to compensate that the level is reduced, a peaking circuit for lifting the high frequency of the demodulation luminance signal is used in the home VTR, and the peaking circuit makes the high frequency of the demodulation luminance signal at the same level as the low range.

In addition to the general tape, a so-called high-sensitivity tape having higher performance than that of the general tape is used as the video tape of the home VTR. In order to fully exhibit the performance of this high-sensitivity tape, it is necessary to make the characteristics of the recording system or the reproduction system different from that of the general tape. As this characteristic is changed differently, the following case is considered, for example.

1. In a recorder in which the luminance signal of the video signal is FM-modulated and magnetically recorded, the amount of emphasis in the detail emphasis circuit which emphasizes the high level small level signal component of the luminance signal before the FM modulation is controlled.

(2) In the recorder in which the luminance signal of the video signal is FM-modulated and magnetically recorded, the equalization amount of the FM equalizer which lifts the low-band signal component of the FM-modulated luminance signal is controlled.

(3) In the reproduction system in which the reproduced luminance signal is FM demodulated, the peaking amount of the FM peaking circuit for lifting the high range of the FM luminance signal before demodulation is controlled.

(4) In the reproducing system in which the reproduced luminance signal is FM demodulated, the amount of cancellation of noise cancellation for canceling the noise of the demodulated luminance signal is controlled.

Next, the recording and reproducing system of the home VTR will be described schematically with reference to FIG.

First, the recorder will be described. In Fig. 3, reference numeral 1 is an input terminal, and a video signal from a TV receiver or the like not shown is input to this terminal. This video signal is input to the LPF 2 to take out the luminance signal, which is input to the AGC 3 to control the level of the synchronization signal to be constant. The video signal input to the input terminal 1 is also input to the BPF (not shown), and the chroma signal is taken out and converted into the low range by the chroma signal processing circuit (not shown).

The luminance signal via the above-described AGC 3 is input to the detail emphasis circuit 4, and the high level low level signal of the luminance signal is emphasized and input to the luminance signal processing circuit 5.

In this luminance signal processing circuit 5, it is input to the FM modulator 6 as an emphasis etc. in which the high range of a luminance signal is emphasized. The low frequency portion of the FM luminance signal modulated by the FM modulator 6 is lifted by the FM equalizer 7, and the region corresponding to the band of the low frequency transformed chroma signal is cut by the next HPF 8. The FM luminance signal via this HPF 8 is input to the recording amplifier 9, mixed with the above-described low-conversion chroma signal from the input terminal 10, and amplified, and supplied to the video head 11. Then, the data is magnetically recorded on the video tape 12.

Next, the reproduction system will be described, and reference numeral 13 denotes a video head, which is shown separately from the video head 11 for the sake of convenience. The video signal reproduced from the video tape 12 by the video head 13 is amplified by the preamplifier 14 and the low frequency conversion chroma signal is extracted by the LPF 15, and the HPF 16 By this, the luminance signal which is FM-modulated is taken out. The chroma signal via the LPF 15 is converted into a chroma signal of the subcarrier band by the chroma signal processing circuit 17 and supplied to the mixing circuit 18 described later.

After the high frequency component (near 5MHZ) is lifted by the FM equalizer 19, the luminance signal via the HPF 16 becomes constant at the FM AGC 20, and is input to the FM demodulator 21 and demodulated. . The luminance signal output from the FM demodulator 21 is appropriately processed by the luminance signal processing circuit 22, and the high frequency component (2 MHZ or more) is lifted by the next peaking circuit 23. The luminance signal via this picking circuit 23 is input to the line noise canceller 24.

In this line noise canceller 24, as shown in detail in FIG. 4, the luminance signal from the input terminal 27 via the picking circuit 23 is transmitted by the 1H delay element 28 to one horizontal syringe slot ( Below 1H The delayed luminance signal and the undelayed original luminance signal are subtracted by a subtractor (indicated by the adder 29, but acts as a subtractor since the polarity is reversed in the 1H delay element 28). From the subtracted signal, only the micro level signal which is regarded as a noise component by the limiter 30 is extracted and the level of the micro level signal is attenuated by the attenuator 31 in half. The indicated subtractor is subtracted from the original luminance signal to cancel the noise component. The luminance signal from which the noise component is canceled is supplied to the noise canceller 25 by the output terminal 33.

In the noise canceler 25, many high frequency components of the noise component are extracted from the luminance signal via the line noise canceller 24, and components larger than a predetermined level are slice-recovered (not shown) from this high frequency component. ), And the output of this slice circuit is subtracted from the gray signal via the line noise canceller 24 to cancel the noise component.

The luminance signal via the noise canceller 25 is input to the mixing circuit 18, mixed with the chroma signal, and supplied to a known CRT (not shown) such as the output terminal 26 to obtain a reproduced image. Lose.

As a video tape used for home VTRs, so-called high-sensitivity tapes are commercially available in addition to general tapes. This highly sensitive tape obtains high regeneration output from the tape by ultrafine magnetization and high layer evolution of the magnetic material, and greatly improves S / N.

In particular, as shown in the characteristic diagram of FIG. 5, the high-sensitivity tape a1 has a higher reproduction output level from the tape than the normal tape b1, and in particular, the low range (1-2 MHZ) in the high range (4-6 MHZ). The output level is higher than that.

Video signals are recorded by this high sensitivity tape When regenerated, the level of the carrier of the reproduced FM signal, the low band of the upper band and the high band of the lower band is lifted, and the reproduced FM signal passing through the limiter is the low band of the carrier, the upper band and the high band of the lower band. The level is higher than that of a normal tape. The low level of the high frequency band and the low frequency band of the upper band of the reproduction FM signal passing through this limiter is relatively lower than the high band level of the low band and the lower band of the upper band as described above. As a result, for the low pass signal level maintained at the constant level of the demodulated luminance signal, the high pass signal level is lower, which is lower than that of the normal tape. When the signal level of the high range is lowered in this manner, it is not sufficiently compensated when the characteristic of the picking circuit 23 is set for the general tape.

FIG. 6 shows the level of the reproduced and demodulated video signal with respect to the high sensitivity tape a2 and the normal tape b2. In the case of the high sensitivity tape, the signal level in the high band is lower than that of the normal tape. Thus, it is known in the art that the signal level in the high range is low, and the reproduced screen becomes cloudy.

In the home VTR, a small level signal component is emphasized in the high range of the luminance signal to be recorded as described above to compensate for the blurring of the reproduced image due to deterioration of the high range in the luminance signal of the recorded and reproduced video signal. The detail emphasis circuit 4 is provided.

The detail emphasis circuit 4 mentioned above is comprised from the HPF 78, the amplifier 79, the limiter 80, the attenuator 81, the adder 82, etc. as shown in FIG. The luminance signal from the AGC 3 input to the input terminal 70 is extracted by the HPF 78, and the high frequency component thereof is amplified by the amplifier 79. As for this amplified high frequency component, a small level signal component is taken out by the limiter 80. FIG. The high level small level signal component via the limiter 80 is interpolated with the luminance signal from the input terminal 70 by the adder 82 after the level is adjusted by the attenuator 81 and the output terminal 84. It is input to the luminance signal processing circuit 5 via.

In the above-described VTR having the detail emphasis circuit 4, the high-frequency small level signal component included in the luminance signal of the video signal to be recorded, i.e., the input detail signal is set for general tape if it is equal to b3 in FIG. It is emphasized in the detail emphasis circuit 4 so as to be b4 in FIG. This is recorded using regular tape When reproduced and demodulated, a signal similar to the input detail signal b3 is reproduced as shown in b5 in FIG.

However, the signal shown in a3 in FIG. 15, which is equal to the input detail signal b3, is emphasized in the detail emphasis circuit 4 whose characteristics are set for general tape, so that the signal a4 is the same as the signal shown in b4. Record using high sensitivity tape When reproduced and demodulated, the level is lower than the above-described input detail signal a3 as shown by a5 in FIG. In this way, the level of the detail signal is lowered and the reproduced picture becomes cloudy.

As described above, the amount of emphasis of the conventional detail emphasis circuit is sufficient to compensate for the blurring of the reproduction screen in the case of the high-sensitivity tape.

In addition, the following are known to automatically exhibit the performance according to the type of the conventional video tape and to automatically compensate for the deterioration of the characteristic according to the type of the video tape.

1) The playback level is detected and stored to determine the type of video tape by the level of the reproduced signal, and the frequency characteristic of the recorder in which the frequency characteristic of the FM luminance signal is adjusted by FM is modulated according to the stored reproduction level. Japanese Patent Laid-Open No. 63-146674.

2) Envelope FM signal is detected and the detection output is used as a control signal to determine the peaking amount of the FM equalizer of the playback system so that the compensation amount of the frequency characteristic does not change even if the frequency characteristic of the video tape is changed. (Japanese Patent Application Laid-Open No. 63-59287).

3) The noise canceler 25 used in the reproduction system, i.e., the high frequency portion where noise in the reproduction feedback signal tends to concentrate is separated by a filter, and a low level signal component is taken out by the slice circuit. The high frequency and low level signals are considered as noise and are subtracted from the original signal. The FM luminance signal reproduced from the video tape is detected by the FM reproduction level detector, and the larger the reproduction level is (for example, in the case of a high sensitivity tape). The slice level of the said slice circuit is made small (Japanese Unexamined-Japanese-Patent No. 1-14178).

On the other hand, in the noise canceller 25 in which the slice level is constant, the original signal components other than the noise are also canceled due to the property of uniformly canceling the high frequency and low level signal components. In this sense, while the S / N is greatly improved, in the case of the high sensitivity tape in which the high frequency level of the reproduced and demodulated luminance signal is low, the amount of cancellation is small. Even in the line noise canceller shown in FIG. 4, only the noise component is canceled, and the micro level signal component (detail signal) is also subtracted to some extent, and the level thereof becomes small.

In the case of the luminance signal having the same correlation as that of the luminance signal before 1H, the level is not attenuated, but when it is not correlated, the level is small as it is not correlated.

The case where these correlations are the same and the case where they are not the same will be explained with reference to FIG. 7 and FIG. X1-X5 in Fig. 7 is the case of the very same correlation, where X1 is the original signal and X2 is the signal before 1H. They are in the same phase relationship. X3 shows the output of the adder 29 and is at the zero level. X4 is the output of the attenuator 31, and is also 0 level. X5 is the output of the adder 32 and a signal identical to the original signal shown by X1 is obtained. Y1-Y5 of FIG. 7 is a case where the phase of the signal before 1H advances by 90 degrees with respect to the original signal, and this signal and the signal before 1H are regarded as a signal of a minute level that cannot be limited by the limiter 30. FIG. Y1 is the original signal, And Y2 is a signal before 1H, , In other words Is displayed. Y3 represents the output of the adder 29, By synthetic formula as It becomes Y4 is the output of the attenuator 31 and is half of the level indicated by Y3, i.e. It is. Y5 is the output of the adder 32, As a synthetic formula Is displayed.

As described above, the original signal Y1 decreases by 30% in the output signal Y5, and the clothes advance 45 °.

Small signals generally have no correlation between lines than large amplitude signals. If it is a large amplitude signal, there is no correlation for each line and it cannot be recognized as a screen, but in the case of a small signal, it can be recognized as a screen even if there is no correlation. As a small signal, for example, irregularities in human skin have no correlation. Z1-Z5 in FIG. 8 is a case where there is no correlation between the original signal and the signal before 1H, Z1 is a convex original signal, and Z2 is a flat 1H signal.

These original signals and the signals before 1H are signals of small amplitude at noon that the amplitude is not limited by the limiter 30.

Z3 shows the output of the adder 29, and is the same convex signal as the original signal. Z4 is an output of the attenuator 31 and is a signal having a width of 1/2 of the original signal.

Z5 is the output of the adder 32, and is a signal having an amplitude of 1/2 of the original signal shown by Z1.

In this way, the line noise castler is less noise, while the level of the detail signal is somewhat smaller, and the level is smaller as it does not correlate with the luminance signal before 1H.

However, it is possible to automatically exhibit the performance according to the type of video tape such as general tape or high-sensitivity tape all day, and to automatically compensate for the deterioration of characteristics according to the type of video tape. Even with the technology, the performance of videotape can not be sufficiently achieved and the characteristics cannot sufficiently compensate for the deterioration.

Next, consider the case where the Japanese Unexamined Patent Application Publication No. 1-14178 is used as the noise canceller described above.

In general, when a color video signal is reproduced by VTR to demodulate a luminance signal, it is known that there is an unnecessary component of about 1.3 MHZ in the demodulated luminance signal. The level of the reproduced chroma signal of the level of this unnecessary component is high. In other words, the higher the color saturation, the higher.

The reason why this unnecessary component occurs is described. In the case of magnetic recording in the VTR, the recording current is subjected to third order distortion by hysteresis characteristics and is magnetized on the tape.

Luminance FM Signal = A sin α

When the low-conversion chroma signal = B sin β, the following equation is obtained on the tape.

Deploy

Likewise

9 is a spectrum in which a magnetized signal on a video tape is reproduced in a video head, and a is a low-conversion chroma signal. B is unnecessary component C is the FM luminance signal D is unnecessary component E, f are unnecessary components Each of these unnecessary components is not a problem since the output level is small with respect to the high frequency unnecessary components e and f.

When the noise of the luminance signal reproduced on the normal tape is canceled by the noise canceller whose noise is varied according to the reproduction level of the reproduced FM luminance signal as described above, the above slice level is large, and thus the above-mentioned unnecessary component b and d are also canceled.

However, the color saturation is high when the noise signal of the luminance signal reproduced on the high-sensitivity tape is high, and when the image such as animation is reproduced, the level of the unnecessary components b and d is relatively large, despite the small slice level described above. Therefore, this unnecessary component is not canceled.

If the unnecessary components b and d are present in the luminance signal, mesh-like noise is generated on one surface of the reproduced screen, resulting in a very bad view.

In the case of a screen with low color saturation, even if the reproduction signal from the high-sensitivity tape is low, the level of the unnecessary components b and d is low, and as a result, the above-mentioned mesh noise is not generated.

The first object of the present invention is to automatically and sufficiently exhibit the performance according to the type of video tape and the like, and also to automatically compensate for the deterioration of the characteristics according to the type of the video tape and the like sufficiently. A magnetic recording and reproducing apparatus can be provided.

The second object of the present invention is to record and reproduce a short wavelength standard signal on the video tape to automatically control the characteristics of the recorder or reproduction system according to the type of video tape, and detect the level of the reproduced standard signal. In a magnetic recording and reproducing apparatus for storing and controlling characteristics of the recording system or reproduction system in accordance with the stored standard signal level, a magnetic recording apparatus or magnetic recording capable of obtaining a short wavelength standard signal without using an independent oscillator. It is to provide a playback device.

It is a third object of the present invention to provide a magnetic recording and reproducing apparatus capable of preventing the aforementioned mesh noise generation.

In order to solve the above problems, the present invention includes a reproduction level detector for detecting a level of a reproduced signal and a memory for storing the reproduction level detected by the detector. And the reproduced level being reproduced is stored in the memory so that the amount of detail of the emphasis in the reproduction system and the amount of equalization of the FM equalizer in the recorder can be controlled in accordance with the stored reproduction level. The level of the reproduced FM luminance signal is detected by the reproduced level detector, and thus the equalization amount of the FM equalizer, the amount of cancellation of the line noise canceller, and the amount of cancellation of the noise canceller in the reproduction system are respectively detected. An apparatus that can be controlled, comprising: a magnetic reproducing apparatus, comprising: line noise canceller means; Detecting means for detecting an envelope level of a component of a first portion of a video signal reproduced from a recording medium, said populating line level indicating a grade quality of said recording medium; The line noise canceler means cannot be executed when the envelope level detected by the detection means is higher than a predetermined envelope level. The line noise canceller means is such that the envelope level detected by the detection means Delaying the luminance signal of the first portion of the video signal during a single horizontal scan period to provide a delayed luminance signal when lower than or equal to the predetermined envelope level, and providing the delayed luminance signal to a first subtraction result signal. To subtract from the undelayed luminance signal of the second portion of the video signal reproduced from the recording medium, and the amplitude exceeds a predetermined value from the first subtraction result signal constituting a noise component in the non-delayed luminance signal. To extract a signal that does not have an amplitude, and output a luminance signal with noise components whose amplitude is canceled therefrom The present invention relates to a magnetic recording and reproducing apparatus having an optional line noise canceller, wherein the signal is subtracted from the luminance signal which is not delayed.

Instead of controlling the equalization amount of the FM equalizer of the reproduction system, the peaking amount of the peaking circuit of the reproduction system may be controlled.

And a chroma level detector for detecting the level of the reproduced chroma signal when the chroma signal recorded by the low pass conversion is reproduced and converted to the subcarrier, and the amount of cancellation of noise canceller in accordance with the chroma level detected by the chroma level detector. A magnetic recording and reproducing apparatus for controlling the

In the magnetic recording and reproducing apparatus configured as described above, at the time of recording the video signal, the signal is recorded and reproduced in advance, and this reproduction level is stored in the memory. According to the stored reproduction level, the amount of emphasis of the detail emphasis circuit of the recorder and the equalization amount of the FM equalizer of the recorder are controlled to record the video signal.

When the video signal is reproduced, the reproduced FM luminance signal level is detected by the reproduction level detector, and according to the detected reproduction level, the equalization amount of the FM equalizer of the reproduction system, the amount of cancellation of the line noise canceller, and the amount of cancellation of the noise canceller are Each controlled.

The peaking amount is controlled when the equalizing amount of the FM equalizer of the reproducing system is controlled instead of the equalizing amount of the reproducing system.

In addition, the chroma signal is detected by the chroma level detector when the chroma signal recorded by the low pass conversion is reproduced and converted to the subcarrier, and the amount of cancellation of the noise canceller is controlled in accordance with the detected chroma level. In the present invention, the FM modulator is provided with a DC voltage source for selectively inputting a DC voltage of a predetermined level, and the output of the FM modulator obtained by inputting the DC voltage to the FM modulator is used as the reference signal.

In the magnetic recording or recording / reproducing apparatus configured as described above, the direct current voltage from the direct current voltage source is input to the FM modulator, whereby a short wavelength reference signal is obtained in the FM modulator.

In order to solve the above problems, the present invention has a means for detecting the level of the reproduced signal and storing it, and the amount of emphasis of the detail emphasis circuit is controlled according to the stored detection level.

In the magnetic recording apparatus configured as described above, the level of the reproduced signal is detected and this detection level is stored. The amount of emphasis in the detail emphasis circuit is controlled in accordance with the stored detection level.

In order to solve the above problems, the present invention provides an FM reproduction level detector for detecting a reproduction level of a reproduced FM luminance signal, means for extracting a noise component from a demodulated luminance signal from the FM luminance signal, and a noise component. Has a slice level for removing components larger than a predetermined level, the slice level being controlled so as to be smaller as the reproduction level is larger, and a self-playing apparatus having a subtractor for subtracting the output of the slice circuit from the luminance signal. A noise canceller in the apparatus comprising: a chroma level detector for detecting a level of a regenerated chroma signal, and controlling a larger slice level of the slice circuit as the detected chroma level is larger. That's it.

In the noise canceller of the present invention configured as described above, the larger the reproduction level of the reproduction FM luminance signal is, the smaller the cancellation amount is, the higher the resolution is, and the larger the chroma level of the reproduction chroma signal is, the greater the cancellation amount is. The unnecessary components included in the signal are removed so that no mesh noise of the reproduction screen is generated.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing the main part of the recording and reproducing system of the home VTR, and FIG. 2 is a block diagram showing the main part of FIG. 1 in detail.

In FIG. 1, the same reference numerals as those in FIG. 3 indicate the same elements, and detailed descriptions thereof will be omitted.

Reference numeral 4a denotes a detail emphasis circuit, similar to the detail emphasis circuit described in FIG. 3, which emphasizes the high level microlevel signal of the luminance signal, but the amount of emphasis is controlled in accordance with the level of the reproduction reference signal described later. different. In other words, when the level of the playback device signal is higher than that of a general tape such as a high-sensitivity tape, the amount of emphasis increases according to this high degree. do.

A luminance signal mute circuit of symbol 34 is used to input a predetermined voltage to the FM modulator 6 by means of a control signal from a microcomputer to be described later when recording a reference signal. For example, a short wavelength signal of 3.8 MHZ) is output. Reference numeral 35 denotes a mute circuit, which, when recording a reference signal, cuts off the chroma signal input from the input terminal 10 to the recording amplifier 9 by a control signal from a microcomputer described later.

Reference numeral 7a is an FM equalizer of the recorder, and similarly to the above-described FM equalizer 7, the low frequency of the FM-modulated FM luminance signal is lifted, but the amount of equalization is controlled. That is, when it is detected that the high sensitivity tape is detected by the level of the reproduced reference signal, the control signal from the microcomputer described later raises the lower range more than in the case of the normal tape (indicated by b3) as shown by the symbol a3 in FIG. The level of the high range of the luminance signal which is raised and reproduced and demodulated is reduced.

Reference numeral 19a denotes an FM equalizer of the reproduction system. Similarly to the FM equalizer 19 described above, the high frequency of the reproduced FM luminance signal is lifted, but the amount of equalization is controlled. In other words, when it is detected that the high sensitivity tape is used according to the level of the reproduced FM luminance signal as described below, the lifting amount of the high range is less than that of the normal tape (indicated by b4) as indicated by a4 in FIG. In addition, the level of the high range of the luminance signal to be reproduced and demodulated is reduced.

Reference numeral 23 is a picking circuit, which lifts the high range of the demodulated luminance signal similarly to the picking circuit 23 described above, but the lifting amount is controlled. That is, when it is detected that the use of the high-sensitivity tape according to the level of the reproduced FM luminance signal is described below, the high range is raised and reproduced more than in the case of the normal tape (indicated by b5) as indicated by a5 in FIG. And demodulation to reduce the level of the high range of the luminance signal is reduced.

Reference numeral 24a denotes a line noise canceller, and similarly to the above-described line noise canceller 24, the luminance signal via the picking circuit 23a is delayed by 1 H, and the delayed luminance signal and the original luminance signal without delay are subtracted. The subtractor extracts only the microlevel signal considered as a noise component by the limiter from the subtracted signal, and cancels the noise component by auditing the microlevel signal from the original luminance signal. The point where a switch (not shown) is provided between the attenuator 31 and the adder 32 of the line noise canceller 24 is different. This switch is opened when the video tape being used is a high-sensitivity tape by the reproduced FM luminance signal, and is judged as described below. The noise canceler is not working.

Numeral 25a denotes a noise canceller. Like the noise canceller 25 described above, many high frequency components of the noise component are extracted from the luminance signal via the line noise canceller 24a, and the high frequency component is larger than a predetermined level. The component is removed by the slice circuit, and the output of the slice circuit is subtracted from the above-mentioned luminance signal, but the cancellation amount is controlled according to the level of the reproduced FM luminance signal. .

The detail emphasis circuit 4a and the noise canceller 25a are used by switching the combined circuit. 2 shows this dual circuit, reference numeral 36 denotes an HPF 37 an amplifier, 38 a limiter, 39 a phase correction circuit, 40 a first glog regeneration switch, 41 an attenuator, 42 an inverting circuit, and 43 2 recording and playback switching switches, 44 is an adder, and 45 is a smoothing circuit. This combined circuit operates as the detail emphasis circuit 4a when the switches 40 and 43 are switched to the recording side, and as the noise canceler 25a when switched to the reproduction side.

First, when operating as a detail emphasis circuit, the high frequency component is taken out by the HPF 36 rather than the luminance signal from the AGC 3 via the input terminal 46, which is amplified by the amplifier 37. do. From the amplified high frequency component, the detail signal is taken out by the limiter 38, the level is attenuated by the attenuator 41, and is added to the luminance signal from the terminal 46 by the adder 44 to output terminal 48. It is supplied to the luminance signal processing circuit 5 through. A control signal of PWM (pulse wide modulator) described later is input from the input terminal 47, which is smoothed by the smoothing circuit 45 to become a DC voltage, and the limiter level of the limiter 38 is changed by this voltage. . If this voltage is high, for example, the limiter level is small, and if the voltage is low, the limiter level is large. If the limiter level is increased, the amount of addition in the adder 44 of the detail signal is increased, and the amount of emphasis is increased. On the contrary, if the limiter level is small, the amount of addition is reduced and the amount of emphasis is reduced.

Subsequently, when operating as the noise canceller 25a, the reproduction luminance signal in the line noise canceller 24a via the input terminal 46 is input to the HPF 36, whereby the high-frequency signal and noise It is taken out. This high frequency signal and noise are amplified by the amplifier 37, and the noise is taken out by the limiter 38. This noise is corrected by the phase correction circuit 39, and the phase shifted from the HPF 36 is corrected so that the phase is aligned with the reproduction luminance signal from the input terminal 46. After the phase is adjusted, the level is adjusted by the attenuator 41. It is added to the luminance signal from the terminal 46 by the adder 44 via the inversion circuit 42. That is, the noise leveled by the attenuator 41 is subtracted by the adder 44 into the luminance signal from the terminal 46. The luminance signal from which this noise is subtracted is supplied to the mixing circuit 18 through the output terminal 48. The noise canceller 25a originally subtracts the noise with the adder 44, but even the detail signal is subtracted from the drawing. As a result, if the tape has a low noise such as a high-sensitivity tape by the control signal described later from the input terminal 47, the limiter level of the limiter 38 is controlled according to the small degree. Conversely, for a noisy tape, such as a regular tape used several times, the limiter level should be increased.

Referring again to FIG. 1, reference numeral 49 denotes a reproduction level detector, which detects and reproduces the reproduction reference signal or the reproduction FM luminance signal from the preamplifier 14 by envelope detection. In the case where the signal from the preamplifier 14 is a reproduction FM luminance signal, it is preferable to direct-flow the signal sampled by the horizontal synchronization signal. The regeneration level detected by the regeneration level detector 49 is converted via the terminal 51 of the microcomputer 50 described above. It is input to 52.

Reference numeral 53 is a chroma level detector, which detects the saturation of the chroma signal from the chroma signal processing circuit 1? And converts it into direct current. The chroma level from the chroma level detector 53 is converted via the terminal 54 of the microcomputer 50. It is input to 55.

The microcomputer 50 is a conversion formula 52, conversion formula Besides the memory 55, the memory 56, the comparator 57, the third recording and reproducing switching switch 58, and the fourth recording and reproducing switching switch 59 are provided.

Conversion formula (52) The reproduction level of the reference signal previously recorded on the standard tape is read in and stored. This stored level is compared with the next read-in level as a reference value and a control signal is output. This control signal, for example, linearly shifts the duty of the PWM (pulse wide modulator) in a low direction when a voltage higher than the reference value is read in, and the duty of the PWM is high during reproduction. Linear movement in the direction. This control signal is stored in the memory 56. Conversion 55 is the conversion formula The control signal from 52 is superimposed by the chroma level from the chroma level detector 53, that is, the color saturation. When the comparator 57 is at the time of writing, when the output of the memory 56 becomes below the set level of the power generation source 60, H Output control signal, otherwise L Output a control signal. Conversion formula during playback When the control signal from (52) becomes above the set level of the voltage source 60 H Outputs a control signal L Output a control signal.

Conversion formula mentioned above The control signal from 55 is supplied to the noise canceler 25a via the terminal 62, and the control signal from the memory 56 is supplied via the terminal 62 to the detail emphasis circuit 4a. Is supplied. The control signal from the comparator 57 is supplied via the terminal 64 to the FM equalizer 7a of the recorder, the FM equalizer 19a of the playback system, the picking circuit 23a, and the line noise canceller 24a. do.

Next, the operation of the VTR configured as described above will be described.

First, in recording a video signal, the amount of emphasis of the detail emphasis circuit 4a of the recorder and the amount of equalization of the FM equalizer 7a can be set according to the video tape used before. The control signal is sent to the luminance signal muting circuit 34 and the muting circuit 35 through the terminal 61 of the microcomputer 50, and the short-wavelength reference signal is output through the FM modulator 6, and the terminal ( The chroma signal supplied to the recording amplifier 9 is cut off via 10).

The short wavelength reference signal from the FM modulator 6 is recorded on the video tape by the video head 11 via the FM equalizer 7a, the HPF 8, and the recording amplifier 9 described above. After recording, the video tape is rewound as it is, and the recorded reference signal is reproduced by the video head 13. The reproduced reference signal is supplied to the LPF 15 and the HPF 16 via the preamplifier 14 and also to the reproduction level detector 49. The playback level from this detector is converted It is stored in the memory 56 via 52. This memory 56 stores the value until the video tape is replaced.

In this state, when the VTR is set to the recording state, the output control signal from the memory 56 is supplied to the above-described detail emphasis circuit 4a via the switches 58 and 59 which are switched to the recording side. The amount of emphasis of this detail emphasis circuit is controlled. It is also input to the comparator 57 via the switch 58 on the output control signal recording side from the memory 56, and from the comparator 57 when the video tape is a high sensitivity tape. H When the control signal is a normal tape L A signal is output, which is supplied to the FM equalizer 7a of the recorder to control the equalization amount of the FM equalizer.

In this manner, during recording, the reference signal is recorded and reproduced in advance so that the amount of emphasis of the detail emphasis circuit 4a and the amount of equalization of the FM equalizer 7a are controlled to be set according to the type of video tape used.

In the state where the amount of emphasis or the like is set, the video signal from the input terminal 1 is recorded on the videotape by the video head 11 by recording the recorder, which is approximately the same as the conventional one described in FIG. Do.

Next, playback will be described. In the reproduction of the VTR, the video signal reproduced by the video head 13 from the video tape is amplified by the preamplifier 14 and supplied to the LPF 15, the HPF 16, and the reproduction level checker 49. The reproduction level detected by the reproduction level detector 49 is a conversion type of the microcomputer 50. The conversion type is converted via the switch 58, which is converted into the control signal described above at 52 and switched to the reproduction side. 55 and comparator 57 are supplied. In the comparator 57, when the video tape used as described above is a high-sensitivity tape, H If the control signal is a regular tape L A control signal is output, and this control signal is supplied to the FM equalizer 19a, the peaking circuit 23a and the line noise canceller 24a, and the equalization amount of the equalizer 19a and the peaking amount of the peaking circuit 23a are controlled. The line noise canceller 24a is controlled to be in an operating state or an inoperative state.

The chroma level detected by the chroma level detector 53 from the LPF 15 via the chroma signal processing circuit 17 is converted. Entered in 55, conversion formula The signal from 52 is superimposed by the color saturation and then supplied to the noise canceller 25a.

In the noise canceler 25a, the larger the regeneration level detected by the regeneration level extractor 49, the smaller the cancellation amount. However, even when the regeneration level is large, the chroma level detected by the chroma level detector 53 is large. At that time, the amount of cancellation is controlled to be large.

In this manner, the peaking amount of the equalizing amount peaking circuit 23a of the FM equalizer 19a of the reproduction system and the operation of the line noise canceller according to the video tape to be used. The video reproduced by the video head 13 from the video tape in a state in which the non-operation is controlled and the cancellation level of the noise canceler 25a is controlled because the video tape to be used and the chroma level of the chroma signal to be reproduced are different. The signal reaches the output terminal 26 in a manner similar to the conventional one described with reference to FIG.

In the above-described embodiment, both the equalization amount of the FM equalizer 19a of the reproduction system and the peaking amount of the peaking circuit 23a are controlled during reproduction, but only one of them may be controlled.

In the above embodiment, the chroma level detector 53 is provided and the chroma level detected by the detector controls the cancellation amount of the canceller 25a. However, if the generation of mesh noise is ignored, the chroma level is ignored. Level detector 53 and conversion This can be done without installing 55.

In the above embodiment, the chroma level detected by the chroma level detector 53 is converted. Conversion formula by typing in (55) The control signal from (52) is superimposed according to the saturation of the color, but the chroma level is converted. Enter this 52 to convert this expression The control signal output from the superimposed color may be superimposed on the saturation of the color. In this case Becomes unnecessary

Next, a second embodiment of the present invention will be described with reference to the drawings.

Figure 16 Records Home VTRs It is a block diagram schematically showing the main part of the reproduction system.

In the figure, reference numeral 201 denotes an input terminal of a recorder, and a video signal for recording obtained by a TV receiver or the like is input from the input terminal. The input video signal is input to the recording luminance signal processing circuit 202, and only the luminance signal is taken out by the LPF or the like. The separated high frequency chroma signal is processed by other means not shown. The extracted luminance signal is input to the FM modulator 204 via a switch 203 described later and FM-modulated. The FM luminance signal from this FM modulator is lifted to the FM equalizer 205 by its low-pass section and input to the adder 207 via the HPF 206. In this adder, it is added to the low-frequency converted chroma signal from the terminal 208, and is added to a video tape (not shown) by the video head 211 via the recording amplifier 209 and the recording / playback switching switch 210. Is recorded.

The color video signal reproduced by the video head 211 from the video tape is supplied to a chroma signal processing circuit and a luminance signal processing circuit (not shown) via a reproduction preamplifier and the color image is reproduced by a CRT (not shown). . The above is used for the well-known home VTR by removing the switch 203.

In the drawing, reference numeral 213 denotes a DC voltage source, and as described above, the recorder When setting to match the video tape using the characteristics of the reproduction system, a predetermined DC voltage is input to the FM modulator 204 via the switch 203. When the predetermined DC voltage is input, the FM modulator 204 outputs a short wavelength reference signal (for example, 3.8 MHz) corresponding to the DC voltage, and the reference signal is recorded on the video tape by the video head 211. do.

The recorded reference signal is reproduced by the video head 211 and supplied to the reproduction level detector 214 via the reproduction preamplifier 212. The reproduction level detector 214 is supplied to the reproduction level detector 214 of the reference signal detected by this reproduction level detector 214. The reproduction level of the reference signal detected by this reproduction level detector 214 is stored in the memory 215. The reproduction level of the reference signal stored in this memory is compared with the reference voltage of the DC voltage source 217 in the comparator 216, and the comparison error signal is supplied to the control signal generator 218.

In other words, the reference voltage is equal to the reproduction level output from the memory 215 when the reference signal is recorded on the standard tape and reproduced.

The control signal generator 218 generates a control signal according to the comparison error signal, which is output via the terminal 219 in the detail emphasis circuit, the FM equalizer 205, and the reproduction system, not shown. A non-FM picking circuit or a noise canceler (not shown) is supplied to control (set) the characteristics of the recorder or reproduction system.

In the VTR having the above-described configuration, after the DC voltage generator 213 is connected to the FM modulator 204 by the switch 203, the characteristics of the recording system or the reproducing system are set, and then the switch 203 is connected to the recording luminance signal processing circuit ( A video recording or reproduction is performed as described above by connecting to the 202 side.

In recording or reproducing the video signal, the characteristics of the video tape used by the characteristics of the recording system or the reproduction system are matched, so that the performance of the video tape can be sufficiently exhibited.

Next, a third embodiment of the present invention will be described with reference to FIG.

17 is a block diagram schematically showing a main portion of a regeneration system of the VTR. In FIG. 17, reference numeral 301 denotes a video tape, and the color video signal recorded on the tape is reproduced by the video head 302. FIG. The color video signal reproduced by this head is amplified by the reproduction preamplifier 303 and supplied to the LPF 304, the HPF 305, and the noise canceller 306. In the LPF 304, only a chroma signal is extracted from the color video signal and supplied to the chroma signal processing circuit 307. In the chroma signal processing circuit 307, the low frequency conversion chroma signal is converted into a subcarrier chroma signal. The HPF 204 extracts an FM luminance signal from the color video signal, and the FM luminance signal is demodulated by the luminance signal demodulation circuit 308.

The noise canceller 9360 is composed of a reproduction level detector 309, a chroma level detector 310, an HPF 311 slice circuit 312, a subtractor 313, a slice level control circuit 314, and the like. The luminance signal from the demodulation circuit 308 is extracted by the high frequency component by the HPF 311, and the high frequency component is supplied to the slice circuit 312. The slice circuit 312 has a predetermined level to the input high frequency component. A slice level for removing a larger component is removed, and a component exceeding this slice level is removed, and a high level low level component (referred to as a noise component) passing through the slice circuit 312 is subtracted from the subtractor 313. Is subtracted from the luminance signal from the luminance signal demodulation circuit 308. The slice level of the slice circuit 312 is subtracted by the signal from the slice level control circuit 314. This slice level controller Circuit (314) Is the level of the FM luminance signal in the reproduction preamplifier 303 detected by the reproduction level detector 309 and the chroma signal in the chroma signal processing circuit 307 detected by the chroma level detector 310. Output signal is controlled.

That is, the slice level of the slice circuit 312 is controlled to be smaller as the reproduction level of the FM luminance signal is larger, and larger as the level of the chroma signal is larger.

Therefore, even when the reproduction level of the FM luminance signal is reduced in chroma noise cancellation amount, when the chroma signal level is large, the unnecessary components b and d are canceled when the noise cancellation amount is increased.

The luminance signal in which noise is canceled in this way is added to the adder 315 from the subtractor 313, and is added to the chroma signal from the chroma signal processing circuit 307 in this adder, and the CRT (not shown) at the output terminal 316 is shown. The image is output to the back and the like to obtain a reproduction image.

A fourth embodiment of the present invention will be described with reference to the drawings.

18 is a block diagram schematically showing the main parts of a recording and reproducing system of a home VTR.

In Fig. 18, reference numeral 415 is an input terminal, and a video signal for recording obtained by a TV receiver or the like is input to this input terminal. The input video signal is input to the luminance signal processing circuit 416, and only the luminance signal is taken out by the LPF or the like. The separated high frequency chroma signal is processed by other means not shown. The extracted luminance signal is supplied to the detail emphasis circuit 417, and the high level small level signal component is emphasized. This detail emphasis circuit 417 has an HPF 8, an amplifier 9, an attenuator 11, and an adder 12, similarly to the detail emphasis circuit 4 described in the prior art, and includes a limiter 10. Except for the same configuration. The limiter 18 in place of the limiter 109 is configured such that the limit level can be varied.

In the detail emphasis circuit 417, the luminance signal in which the high level small level signal component is emphasized is input to the recorder luminance signal processing circuit 419, and the FM signal is modulated after the high frequency portion of the luminance signal is emphasized more than the low frequency portion, and other not shown. It is added to the chroma signal converted into the low range by the means and amplified by the recording amplifier 420. The video signal via the recording amplifier 420 is recorded. It is supplied to the video head 422 through the reproduction switching switch 421 and recorded on the video tape 423.

At the time of reproduction, the video signal reproduced by the video head 422 in the video tape 423 is recorded. Amplified by a reproduction preamplifier 424 via a reproduction switching switch 421, processed by a known chroma signal processing circuit and a luminance signal processing circuit (both not shown) to reproduce an image by a CRT (not shown). do.

The recording system and reproducing system of the above-described VTR are the same as those of the household VTR generally known except that the limit level of the limiter 418 is variable.

Record in the VTR of FIG. An oscillator (not shown) for generating a signal of short wavelength in the reproduction frequency band, for example, a signal of 3.8 MHZ corresponding to the front end of a synchronization signal of an FM modulated PAL video signal, is provided. Is supplied to the recording amplifier 420 described above. The short wavelength signal is recorded on the video tape 423 by the video head 422. The recorded short wavelength signal is rewound by the video head 422 after being rewound by the video tape 423 and amplified by the reproduction preamplifier 424. The short wavelength signal reproduced in this manner is envelope-detected by the reproduction level detector 425, and the reproduction level is detected. This detected reproduction level is stored in the memory 426. In other words, this stored reproduction level is not erased until the video tape 423 is ejected. This stored reproduction level is input to the detail amount control circuit 427. In this diet amount control circuit, the reproduction level of the normal tape is stored in advance, and the stored reproduction level and the input reproduction level are compared, and the limit level of the limiter 418 varies according to the error caused by this comparison. .

In particular, when the video tape 423 is a normal tape, the reproduction level stored in the detail amount control circuit 427 and the reproduction level input to the detail amount control circuit are the same level, so that the limit level of the limiter 418 is set. When the video tape 423 is a high-sensitivity tape, the reproduction level stored in the detail amount control circuit 427 is compared, and the level of the reproduction level input to the detail amount control circuit is high. The limit level is variable and relatively high levels of components will also pass through the limiter 418.

Accordingly, in the detail emphasis circuit 417, characteristics are set such that the high level small level signal component is emphasized more than in the case of the normal tape.

As described above, when a high sensitivity tape is used, the characteristics of the detail emphasis circuit 417 are automatically set for the high sensitivity tape. The high range of the reproduced video signal is obtained at a sufficient level, and the reproduced picture is not blurred.

In the above embodiment, an oscillator for generating a short wavelength signal of 3.8 MHZ is used for test recording and reproduction. Instead, the DC voltage corresponding to the leading level of the synchronization signal is supplied to the FM modulator in the recorder luminance signal processing circuit 419. The FM modulator may generate a short wavelength signal of 3.8 MHz. This short wavelength signal is not limited to 3.8 MHZ.

As described above, instead of recording a short wavelength signal as a test signal, a video signal from the input terminal 415 is recorded through a recorder, and this is reproduced as shown in FIG. With sample The holding circuit 429 may be disposed so as to be disposed. In Fig. 19, reference numeral 430 denotes an input terminal, to which an FM signal from the reproduction preamplifier 424 is supplied. The FM signal is supplied to the luminance signal demodulation circuit 431 in the reproduction level detector 425 described above. The luminance signal demodulation circuit 431 is a part of the luminance signal processing circuit described above. The demodulated luminance signal is output from the output terminal 432 to the rear stage and supplied to the horizontal synchronous separation circuit 428, and the horizontal synchronization signal is supplied. Are separated. Sample mentioned above The hold circuit 429 is supplied with an envelope detected signal of the reproduction FM signal from the reproduction level detector 425, and a stable portion corresponding to the horizontal synchronization signal of this signal is horizontal from the horizontal synchronization separation circuit 428. Sampled and held by the sync signal. In this way the sample The held reproduction level is stored in the memory 426, and the stored reproduction level is supplied to the detail amount control circuit 427 through the output terminal 433. [0035] FIG.

As the separated horizontal synchronizing signal, a horizontal synchronizing signal obtained through a known AFC circuit may be used.

In the above embodiment, the limit level of the limiter 418 is varied by the output of the detail amount control circuit 427, but instead, the attenuation amount of the attenuator 411 is controlled by the output of the detail amount control circuit 427. You may also do so. According to this, when using a high-sensitivity tape, you may set a characteristic so that the attenuation amount of the attenuator 411 may be small by the detail emphasis circuit 417 in order to emphasize the high level small signal component more.

A fifth embodiment of the present invention will be described with reference to FIG.

20 is a block diagram schematically showing the main parts of a regeneration system of the VTR. In Fig. 20, reference numeral 508 denotes a video tape, and the video signal reproduced by the video head 509 on this tape is amplified by the reproduction preamplifier 510, and the reproduction level detector 511, HPF 512 and LPF ( 513). In the playback level detector, the level of the video sync signal, for example, It is held and the level of this video signal is detected as a DC level. The detected DC level is input to the comparator 514 and compared with the reference voltage from the DC voltage source 515. This reference voltage is set to a value higher than the recording / reproducing level when the standard tape is used as the video tape 508. When the DC level is higher than the reference voltage, the switch 516 described later is opened, and when the DC level is low, the switch is closed.

In the HPF 512, a luminance signal is extracted from the video signal, and the luminance signal is an FM demodulation lamp in the luminance signal processing circuit 517, and is de-emphasized in the main de-emphasis 518 to produce a line noise canceller 519. Is supplied. This line noise canceller 519 is composed of a 1H delay element 501, an adder 502, a limiter 503, an attenuator 504, an adder 505, and the like, as described in the conventional example. And a switch 516 interposed between the adder and the adder 505. When the switch 516 is closed, a signal from the attenuator 504 is supplied to the adder 505 to bring the line noise canceller 519 into an operating state, but when the switch is opened, the attenuator 504 The signal to be supplied to the adder 505 of the circuit is cut off, and the line noise canceller 519 is made inoperative.

Via line noise canceller 519 from main deemphasis 518 (when line noise canceller 519 is inactive), do not pass through line noise canceller. Is supplied. The noise canceller, as is known, separates the high frequency components that are likely to concentrate noise in the reproduction luminance signal with a filter, extracts low level signal components by the slice circuit, and considers the high frequency and low level signals as noise. To subtract the original luminance signal. The luminance signal via the noise canceler 520 is supplied to the adder 521.

In the LPF 513, only the color signal which has been low-pass converted from the video signal from the reproduction preamplifier 510 is taken out and supplied to the color signal processing circuit 522. In the color signal processing circuit 522, the low frequency conversion color signal is converted into the subcarrier color signal.

The color signal from the color signal processing circuit 522 and the luminance signal from the noise canceler 520 are added by the adder 521 and supplied to a CRT (not shown) via the output terminal 523 to reproduce the color image. do.

When a general tape is used as the video tape 508 in the VTR, the DC level from the reproduction level detector 511 is lower than the reference voltage from the DC voltage source 515, so that the switch 516 is closed. Therefore, the line noise canceller 519 is in an operating state. On the other hand, when a high sensitivity tape is used, the DC level from the regeneration level detector 511 is higher than the reference voltage from the DC voltage source 515, so that the switch 516 is opened so that the line noise canceller 9519 is non- It becomes the operating state.

The present invention has a reproduction level detector for detecting the level of the reproduced signal as described above, and a memory for storing the reproduction level detected by the detector.

In recording the video signal, the signal is recorded and reproduced in advance, and the reproduction level is stored in the memory, and the amount of emphasis of the detail emphasis circuit of the recorder and the equalization amount of the FM equalizer of the recorder are controlled according to the stored reproduction level. The video signal is recorded. When the video signal is reproduced, the level of the reproduced FM luminance signal is detected by the reproduction level detector, and the equalization amount (or peaking of the peaking circuit) of the FM equalizer of the reproduction system is detected according to the detected reproduction level. Amount), the amount of cancellation of the line noise canceller and the amount of cancellation of the noise canceller are respectively controlled, and the video recording tape is a magnetic recording / reproducing apparatus that is capable of controlling the characteristics according to the type of the video tape over a few places. It is possible to fully exhibit the performance according to the type of tape and deterioration of the performance according to the type of tape. Can be sufficiently compensated.

In addition, when the chroma signal recorded by the low frequency conversion is reproduced and converted into the subcarrier, the level of the reproduced chroma signal is provided with a detector for detecting the chroma level, and according to the chroma level detected by the chroma level detector, Since the magnetic recording and reproducing apparatus is configured to control the amount of cancellation, unnecessary components fed to the reproduction luminance signal due to the chroma signal can also be canceled to eliminate the mesh noise on the reproduction screen.

The present invention is a magnetic recording or recording / playback apparatus in which an information signal such as a luminance signal of a video signal for recording is FM-modulated and has an FM modulator in a recorder, which records and reproduces a reference signal, and the level of the reproduced signal. In accordance with the above, the characteristics of the recording or reproducing system of the information signal are controlled, and the characteristics of the recording or reproducing system are set to match those of the magnetic recording medium such as video tape. It is equipped with a feeder voltage source to input and uses the output of this FM modulator obtained by inputting a DC voltage to the FM modulator as a reference signal. Therefore, it is possible to generate a short wavelength reference signal without using an independent oscillator. can do.

The present invention provides an FM reproduction level detector for detecting a reproduction level of an FM luminance signal reproduced as described above, means for extracting a noise component from a luminance signal demodulated from the FM luminance signal, and a component larger than a predetermined level in the noise component. A noise canceller in a magnetic reproducing apparatus having a slice level for removing and having a slice circuit controlled to be smaller as the reproduction level is larger and a subtractor for subtracting the output of the slice circuit from the luminance signal. And a chroma level detector for detecting the level of the chroma signal, and the larger the detected chroma level, the larger the slice level of the slice circuit is. Therefore, the slice level of the slice circuit is smaller as the reproduction level of the FM luminance signal is larger. In addition, the greater the chroma signal level, the larger the reproduction of the FM luminance signal. Even when the level is large and the noise cancellation amount is small, the noise cancellation amount is large when the chroma signal level is large, and the above-mentioned unnecessary components are canceled so that the reproduction screen can control the mesh noise.

The present invention is a magnetic recording apparatus in which a luminance signal of a video signal for recording is an FM modulator and is unilaterally recorded, and has a detail emphasis circuit for emphasizing a high level small level signal component of the luminance signal before FM modulation. And a means for detecting the level of the reproduced signal and storing it, and the amount of the emphasis of the detail emphasis circuit is controlled according to the stored detection level, and thus the magnetic recording medium used by the level of the reproduced signal. Can be determined and automatically set to the optimum amount of emphasis for this magnetic recording medium, so that the high frequency level of the reproduced signal is low, thereby preventing blurring of the reproduced screen.

The present invention delays the luminance signal of the reproduced video signal between one horizontal syringe as described above, subtracts this delayed luminance signal and the non-delayed luminance signal with a subtractor, and considers the subtracted signal as a noise component by the limiter. A magnetic reproducing apparatus having a line noise canceller that extracts only a small level signal and subtracts the small level signal into a luminance signal to substantially cancel out noise components, comprising: means for detecting a level of a reproduction video signal; Since the line noise canceller does not operate when the playback level detected by the means is higher than the predetermined level, the line noise canceller is automatically prioritized with detail reproducibility when a video tape with a low noise such as a high sensitivity tape is used. The canceler can be deactivated.

Claims (3)

A magnetic regeneration device comprising: line noise canceller means; Detecting means for detecting an envelope level of a component of a first portion of a video signal reproduced from a recording medium, said envelope level indicating a grade quality of said recording medium; The line noise canceller means cannot be executed when the envelope level detected by the detection means is higher than a predetermined envelope level; The line noise canceller means is adapted to provide a delayed luminance signal when the envelope level detected by the detection means is lower than or equal to the predetermined envelope level, during the single horizontal scanner. Delaying the luminance signal, subtracting the delayed luminance signal from the non-delayed luminance signal of the second portion of the video signal reproduced from the recording medium to provide a first subtraction result signal, the amplitude of which is not delayed luminance From the first subtraction result signal constituting the noise component from the signal, a signal that does not exceed a predetermined value is extracted, and the predetermined amplitude is derived from the luminance signal which is not delayed to output a luminance signal having the canceled noise component therefrom. Selective line noise cancellation characterized by subtracting the signal not exceeding the value A magnetic recording and reproducing apparatus having a, The magnetic recording and reproducing apparatus according to claim 1, wherein the first portion of the envelope includes a reproduced FM luminance signal of the video signal. 2. The apparatus according to claim 1, further comprising: reproducing means for reproducing an FM luminance signal of said first portion of said video signal and said second portion of said video signal; And demodulating means for frequency demodulating said FM luminance signal to obtain said luminance signal of said first portion of said video signal and said luminance signal of said second portion of said video signal. Magnetic recording and reproducing apparatus having a canceller.