JPS61292494A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To reproduce a clear image of high S/N by recording and reproducing in the same mothod as the conventional technique when a frequency band of a luminance signal is comparatively narrow, and prohibiting the recoding and the reproduction of at least an FM sound signal in the case of the frequency band being wide, and windening the frequency band to the frequency band in which the FM sound signal is set. CONSTITUTION:By a switch SW1, from an automatic gain control (AGC) circuit 2, a character signal is directly supplied to a luminance signal processing circuit 5, so as to be the character signal FM modulated throughout the whole required frequency band. Therefore, switches SW2-SW4 controlled by a switch control circuit 18 are provided and the FM modulated character signal from an FM modulator 6 is not passed through a high-pass filter (HPF) 7 but supplied to a recording amplifier 8 in the wide frequency band then there are intercepted between an FM sound signal trap circuit 16 and the recording amplifier 8 and between an FM modulator 21 and the recording amplifier 8. Thereby, the recording of the FM sound signal is prohibited and the frequency modulated character signal is recorded in the wide frequency band.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention angle-modulates a luminance signal, low-frequency converts a carrier color signal, and frequency-modulates an audio signal to convert the frequency band into an angle-modulated luminance signal. and the frequency band of the low-frequency-converted carrier color signal, and these signals are combined and supplied to the magnetic head to record and reproduce color television signals. Regarding equipment.

[Background of the invention]

Conventional helical scan video cheapre □′
In a magnetic recording and reproducing device such as Korg, when recording and reproducing a color television signal, the luminance signal is frequency modulated and the carrier chrominance signal is The audio signal is frequency-modulated, and as shown in FIG. 2, a frequency-modulated luminance signal (hereinafter referred to as FM luminance signal) is obtained.
The frequency band Yym of the frequency band Yym is set to the high band side, and the frequency band C of the low band converted carrier color signal (hereinafter referred to as the low band converted carrier color signal) is set to the low band side, and the frequency band Yym of the frequency modulated audio signal (hereinafter referred to as the low band converted carrier color signal) is set to the low band side. , FM audio signal) frequency band At
M is set between the frequency band YFM of the FM luminance signal and the frequency band C of the low frequency conversion carrier color signal, and these signals are combined for recording and reproduction.

In this case, a pilot signal P for performing tracking control during reproduction is also superimposed on the low frequency side of the low frequency conversion carrier color signal.

According to this method, very good characteristics regarding reproduced images and sounds can be obtained as a home-use magnetic recording/reproducing device. On the other hand, teletext broadcasting has begun in which a character signal is superimposed on the vertical retrace period of a color television signal, but when this character signal is recorded and reproduced using the conventional magnetic recording and reproducing device described above, the character signal deteriorates. There was a problem.

To explain this in more detail using the K3 diagram, the transmission bit rate of the character signal is 5.73 Mbits/
sec (815 times the color subcarrier frequency) 11 is adopted, and the signal format is binary NR and Z, but it is shaped into a squared cosine wave to have a spectrum most suitable for digital transmission. Further, the steady amplitude of the character signal is suppressed to 70% of the white peak of the luminance signal in consideration of overshoot. Therefore, the frequency characteristic of a single pulse of a character signal is as shown by the blank line in FIG. Clear character prints can be obtained from such a character signal, which requires at least 5.73 ÷ 2 = 2.86 MHz.
In Figure 3, -6d
B is set to 2.86 MHz.

On the other hand, when recording and reproducing a color television signal in which each signal component has a frequency band as shown in FIG. 2, the FM luminance signal is band-limited using a filter etc. The frequency characteristic of the luminance signal obtained by demodulating the reproduced FM luminance signal is K as shown by the broken line B of the third factor. In this case, the frequency is still 2.86 MHz, although it differs depending on the machine of the magnetic recording/reproducing device.
The frequency band is -7 to -15 dB, which is narrower than the frequency band of the character signal. For this reason, if the character signal superimposed on the vertical retrace period of a color television signal is directly FM modulated and recorded and reproduced, this character signal becomes 2.86 M
Hz is not transmitted, making it impossible to print clear character images.

Therefore, in order to obtain a clear character image print, it is necessary to change the frequency of the FM carrier modulated by the luminance signal to I! It is conceivable that the frequency be increased higher than that of the prior art shown in FIG. 2, and that even if the character signal is FM modulated, it can be recorded and reproduced sufficiently up to 2.86 MHz. however,
In this way, the frequency band of the FM luminance signal and the FM-modulated character signal is further expanded to the high frequency side, and the attenuation on the high frequency side becomes large due to the influence of the frequency and number characteristics of the head-tape system. For this purpose, the S/
N decreases, and the image quality of reproduced color television signal images and character images deteriorates.

Furthermore, magnetic recording and reproducing devices are usually configured so that they can not only receive and record television programs, but also record and reproduce color television signals from video cameras. By the way, the color television signal from a video camera has a wider frequency band, such as a luminance signal, than the color television signal in a television program, and for this reason, the reproduced image is clearer than the reproduced image of a television program. should be obtained.

However, when a color television signal from such a video camera is recorded on a magnetic recording/reproducing device and then reproduced for image reproduction on a television receiver, the frequency band of the FM luminance signal is limited as described above. As a result, the high-frequency components of the reproduced luminance signal are attenuated and the frequency band becomes narrow, which makes it difficult to reproduce images by supplying a color television signal directly from a video camera to a television receiver. In comparison, the quality of the reproduced image will deteriorate significantly.

As described above, in the conventional technology, wideband luminance signals such as character signals processed as luminance signals and luminance signals of color television signals from video cameras are recorded and reproduced with the frequency band narrowly limited. It turns out.

[Purpose of the invention]

The purpose of the present invention is to solve the problems of the above-mentioned conventional technology, to prevent the 8/N deterioration of the luminance signal, and to enable recording and reproduction of wideband luminance signals in the required frequency band.
To provide a magnetic recording/reproducing device capable of obtaining a clear reproduced image at a height of 87N.

[Summary of the invention]

In order to achieve this object, the present invention records and reproduces a color television signal whose luminance signal has a relatively narrow frequency band by using a method similar to that of the prior art as shown in FIG. When the frequency band of the luminance signal is wide, at least FM
The feature is that the frequency band is extended to include the frequency band where the M audio signal is set.

[Embodiments of the invention]

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

FIG. 1 is a block diagram showing an embodiment of a magnetic recording/reproducing apparatus according to the present invention, and FIG. 1(a) shows a recording system.

Φ) in the figure is the reproduction system. In FIG. 1(a), 1 is an input terminal, 2 is an AGC (automatic gain control) circuit, 3 is a Y-shaped filter, 4 is an LPF (low-pass filter), and 5
is a luminance signal processing circuit, 6 is an FM modulator, 7 is an HPF (high pass filter), 8 is a recording amplifier, 9 is a magnetic head,
10 is a magnetic tape, 11 is a BPF (band pass filter)
, 12 is an ACC (automatic chroma control) circuit, and 13 is a carrier color signal processing circuit.

14 is a frequency converter, 15 is an LPF, 1-6 is an audio signal trap circuit, 17 is a synchronous separation circuit, 18 is a switch control circuit, 19 is an input terminal, 20 is a non-linear circuit,
21 is an FM modulator, and swi to SW4 are switches.

In addition, 22 is a preamplifier, 23 is
is an H'PF, 24 is an AGC circuit, and 25 is an HPL (bypass limiter) circuit.

26 is a dropout compensation circuit, 27 is an IH (one horizontal period) delay line, 28 is an FM demodulator, 29 is an LPF, 30 is a noise cancel circuit, 31 is a line noise canceler A
/ circuit, 32 is a mixing circuit, 33 is an output terminal, 34 is an LP
F, 35 is frequency converter, 36 is BPF, 37 is A
CC circuit, 38 is a carrier color signal processing circuit, 39 is a BPF,
40 is an AGC circuit, 41 is an FM demodulator, 42 is a noise reducer, 43 is an output terminal, and SW5 to SW9 are switches, and parts corresponding to those in FIG. 1(a) are given the same reference numerals.

In this embodiment, a predetermined IH or 2H of vertical retrace period is used.
The color television signal of a broadcast program on which a character signal is superimposed during the period , is the target KL, and this character signal is a broadband luminance signal. First, the recording system shown in FIG. 1(a) will be explained.

In the figure, input terminal 1 receives a color video signal of a color television signal to be recorded, and input terminal 19 receives a color video signal of a color television signal to be recorded.
are respectively supplied with audio signals.

A predetermined I of the vertical blanking period of this color television signal.
At the time of teletext broadcasting, a text signal is supplied over H or 2H, but once over this specified IH or 2HK
．． Xf7+SW1 to SW4 are closed to the A side, and otherwise these switches 8W1 to 8W4 are closed to B111. However, even during the predetermined IH or 2H period, during the color burst signal period, the switches SW1 to SW8W4
closes to the B side.

After the color video signal supplied to the input terminal l is leveled at a constant level by the AGC circuit 2, the color video signal is sent to the A of the switch 8W1.
and the Y-shaped filter 3. Color image 1# with Y-shape filter 3! The carrier color signal interleaved on the high frequency side of the signal is attenuated, and the carrier color signal remaining at this time is further attenuated by the LPF 4 to extract only the luminance signal. This luminance signal is supplied to the B side of the switch SW1.

In the following, periods other than the above-mentioned predetermined IH or 2H period (hereinafter referred to as character signal period) in which the character signal of the vertical blanking period of the color television signal is superimposed will be explained. Switches SW1 to SW8W4 are closed to the B side. ing.

Therefore, the luminance signal output from the LPF 4 is supplied to the luminance signal processing circuit 5, where emphasis, dynamic emphasis, clip, etc. are processed, and then FM modulated by the FM modulator 6. The obtained FM luminance signal is
At step 7, the frequency band portion in which the FM audio signal and the low frequency conversion carrier color signal are set is suppressed and limited to the frequency band Yrm shown in FIG. 2, and then supplied to the recording amplifier 8 via the switch SW2.

On the other hand, from the color video signal supplied to input terminal 1, BP
A carrier color signal is extracted at FII. This carrier color signal is
The color burst signal is level-adjusted in the ACC circuit 12 so that the level is constant, and after predetermined processing is performed in the carrier color signal processing circuit 13, the frequency converter 14 and the Li
'F15 performs low frequency conversion. The obtained low-frequency converted carrier color signal is sent to the audio signal trap circuit 16 as FMf7i! The frequency band portion in which the signal is set is trapped and, after being limited to the frequency range C shown in FIG. 2, is supplied to the recording amplifier 8 via the switch 8W3.

Furthermore, the audio signal supplied to the input terminal 20 is processed by the non-rear circuit 20 to suppress the noise generated during recording, and by the FMK modulator 21 to adjust the frequency in the AVIF range 89 shown in Figure 2. FM is broadcasted in a way that makes me feel depressed. The obtained Mf signal is supplied to the recording intensifier 8 via 8W4t.

The recording amplifier 8 receives the "M" signal.

The low-pass converted carrier color signal and the FMii voice signal are combined and amplified. This composite signal is supplied to the magnetic head 9 and recorded on the magnetic tape 10.

Next, in the character signal section, the switches 8W1 . -8V'V4 closes to the A side.

Thereby, the character signal from the input terminal 1 passes through the AGC circuit 2, avoids the Y-shaped filter 3 and the LPF 4, and is supplied from the switch 8W1 to the luminance signal processing circuit 5. The character signal processed there is FM-modulated by the FM modulator 6, and is supplied to the recording amplifier 8 from the switch SW2, avoiding the HPF 7.

Friend, the color burst signal is supplied from the switch SW3 to the recording amplifier 8, but since the switch SW4 is closed to the A side, no FM audio signal is supplied. Therefore,
In the recording amplifier 8, the FM modulated character signal and the color burst signal are combined and amplified. This composite signal is supplied to the magnetic head 9 and recorded on the magnetic tape 10.

” In such a recording system, Y-shaped filter 3 and L-shaped filter 3
When using PF4 to extract the luminance signal from the color video signal, it is important to note that if the carrier color signal remains in the high range of the luminance signal, this will interfere with the FM audio signal and cause buzz in the reproduced audio. This is to ensure that there is no such thing. That is, although the carrier color signal can be sufficiently suppressed using only the Y-shaped filter 3, errors may occur in the filter characteristics and the carrier color signal may not be sufficiently attenuated. In such a case, the color subcarrier remains with relatively large energy, and the luminance signal processing circuit 5 applies emphasis to the high frequency range in order to improve the S/N of the high frequency range of the luminance signal. The luminance signal is then subjected to FM modulation, but at this time, if the carrier color signal remains on the high frequency side of the luminance signal, the color subcarrier will be emphasized. Therefore, F.M.
A high-energy color subcarrier component exists on the low-frequency side of the luminance signal, that is, close to the FM audio signal.
This affects the FM audio signal and causes buzz in the reproduced audio. For this purpose, an L
P F 4 is provided so that the color subcarrier in the high range of the luminance signal is sufficiently attenuated. Of course, the audio signal is not combined with the FM luminance signal or the low frequency conversion carrier color signal as shown in FIG.
If recording is to be performed at a different position, PF'4 can be removed, or a wideband filter can be used to remove high frequency noise.

However, when the character signal is passed through the comb-shaped filter 3 and LPF 4, the frequency band of the character signal is limited to be narrower than the originally required frequency band (2.86 MHz in the above example). For this purpose, in this embodiment switch 8
W1 is provided so that the character signal is directly supplied from the AGC circuit 2 to the luminance signal processing circuit 5, so that the character signal is FM-modulated over the entire required frequency band.

Nine, for HPF7, the frequency band Yrw of the FMM degree signal is
As shown in Figure 2, the frequency band AFM of the FMM voice signal
This is to avoid overlapping with the frequency band C of the low frequency conversion carrier color signal. By the way, this HPF7
The cutoff frequency of is Y-shaped filter 3 and LPF 4.
Since it corresponds to the cutoff frequency of the synthesis filter characteristic, the character value FM modulated by the FM modulator °
This HPF issue? The frequency band of the resulting frequency-modulated character signal is determined by passing the signal to f4 extracted by Y-shaped filter 3 and L P F 4.
The frequency band is narrower to the same extent as the frequency band of the signal obtained by M modulation.

For this reason, in this embodiment, switches SW2 to SW4 are
is provided, and supplies the FM modulated character signal from the F'M & modulator 6 to the recording amplifier 8 without passing it through the HPF 7, and with this, the FM modulated character signal is supplied to the recording amplifier 8 without passing through the HPF 7. k
The four-signal trap circuit 16 and the recording amplifier 8 are cut off, and the MM modulator 21 and the recording amplifier 8 are cut off.

This prohibits recording of the FMit voice signal, and since there is no carrier color signal during the vertical retrace interval, the frequency-modulated character signal is recorded in a wide frequency band.

FIG. 4 shows the recording frequency band Yt- of this frequency-modulated character signal, which includes the frequency band AFM to which the FM sound signal shown in FIG. 2 is set, and the low frequency conversion carrier color signal is set. frequency band C.

Here, the switches 8W1 to 8W4 are the switch control circuit 1
8. The character signal is superimposed over a predetermined period (i.e., a character signal section) spanning IH or 2H, respectively, from the IOHth to the 21st vertical blanking period and from the 273rd to 284th vertical blanking period of the color television signal frame. , switch 8W during this predetermined period.
Switch SW1 to SW4 to the A side. However, even in this character signal section, the switches 8W1 to 8W4 are switched to the B side while the color burst signal is present. This is due to the following reason. Since there is no carrier color signal during the above-mentioned vertical retrace period, the switch SW3 is originally unnecessary, but if it is not provided, the noise output from the character signal section audio signal trap circuit 16 will be FM modulated. It will be mixed with the character signal. For this purpose, a switch SW3 is provided, but if this switch is closed to the A side over the entire character signal period, the color burst signal present within this period will be lost. On the other hand, the response of the PC circuit of a television receiver is slow, and if the color burst signal is absent when it starts responding with the color burst signal supplied after the burst blanking period within the vertical retrace period, the color burst The response to the signal becomes increasingly slow and the hue becomes undefined at the top of the playback screen. For this reason, even in the character signal section, the switch 8W3 is closed to the B side during the period where the color burst signal exists.
This prevents the color burst signal from being lost.

Therefore, the color video signal is supplied from the input terminal 1 to the synchronization separation circuit 17, where the vertical synchronization signal VD is separated and the burst flag pulse BP is output. In the switch control circuit 18, a pulse representing the entire character signal section is formed based on the vertical synchronization signal VD, and a switch pulse is formed by subtracting the period of the burst flag pulse BP from the period of this pulse. The switches SW1 to SW8W4 are controlled.

Alternatively, the switch control circuit 18 may close the horizontal blanking period switches 8W1 to SW4 in the character signal section to the B side. In this case, not only the color burst signal but also the horizontal synchronization signal will not be lost.

Furthermore, the switches SW1 to SW4 may not be controlled simultaneously by the switch control circuit 18, but may be controlled separately. For example, in the character signal section, switches SWI and SW2 are closed during the horizontal blanking period BIIIK.

Switch SW3 is set during period B when the color burst signal exists.
switch SW4 can also remain closed to A[ throughout this character signal interval.

It goes without saying that a broadband LPF may be provided between the AGC circuit 2 and the A side of the switch SWI to remove high frequency noise from the character signal.

Next, the reproduction system shown in FIG. 1 Φ) will be explained.

In the figure, a signal recorded on a magnetic tape 10 as explained in FIG. 1(a) is reproduced by a magnetic head 9 and amplified by a preamplifier 22. To explain, the switches SW5 to SW9 are closed to the B side by the switch control circuit 18.

The regenerated signal having the frequency characteristic shown in FIG. 2, which has been amplified by the preamplifier 22, is supplied to the IPF 23, where the CFM luminance signal is separated. This FM Hikaru F! L signal is switch sW;
through the AGC circuit 24, the level is adjusted to a constant level, and the H
After the PL 25 performs processing to prevent frequency spectrum inversion, the dropout compensation circuit 26 removes the dropout by the delayed FMnKM signal from the IHil extension @27.

'yM/4ILllI unit 28 decodes the signal. The luminance signal obtained by the FM demodulator 28 has out-of-band noise removed by the LPF 29, and then is supplied to the noise canceling circuit 3 (l) via the switch SW6 to remove low-level noise in the high frequency range. Furthermore, the tin salt is supplied to the noise canceling circuit 31 via the switch SW7 to improve the S/N using line correlation.The luminance signal output from the line noise canceling circuit 31 is , are supplied to the mixing circuit 32 via the switch SW8.

Moreover, the reproduction signal output from the preamplifier 22 is LPF
34 to separate the low-pass converted carrier color signals. This low-pass converted carrier color signal is frequency-converted by a frequency converter 35, and a carrier color signal in the original frequency band is obtained by a BPF 36. This carrier color signal is level-adjusted in the ACC circuit 37 so that the color burst signal has a constant level, and after being subjected to predetermined processing in the carrier color signal processing circuit 3B,
The signal is supplied to the mixing circuit 32 via the switch 8W9. Therefore, a color video signal is obtained from the mixing circuit 32 and supplied to the output terminal 33.

Furthermore, the reproduction signal output from the preamplifier 222 is BP
It is supplied to F39 and the FM audio signal is separated. This F
The level of the M audio signal is made constant by the AGC circuit 40, and then demodulated into an audio signal by the FM demodulator 41. This audio signal is supplied to the output terminal 4Δ after noise is removed by a noise reducer 42 having a characteristic opposite to that of the non-rear circuit 20.

Next, in the character signal section, the switch control circuit 18
Accordingly, the switches SW5 to SW8 are as shown in Fig. 1(a) K
It operates in the same way as the switching switches SW1 and 5Vi2.
The switch SW9 operates similarly to the switch S'W3 in FIG. 1(a) and closes to the A side.

The reproduced signal from the preamplifier 22 in this character signal section has the frequency characteristics shown in FIG. 4, and the frequency band Y in FIG. 4 of the FM-modulated character signal at this time
HPF23 is removed by closing switch SW5 AIIK so as not to limit F-, and FM@[
In order not to limit the frequency characteristics shown in FIG. 3 of the character signal demodulated by the modulator 28, the LPF 29 is removed by closing the SW 6 to the A side.

The noise canceling circuit 30 detects low-level high-frequency noise in the input signal and performs subtraction processing on the input signal to remove this noise. At this time, some of the high-frequency components of the input signal are removed. I end up. For this reason, when a broadband character signal is passed through the noise canceling circuit '30, the S/N ratio of the character signal is improved, but its frequency characteristics and waveform are deteriorated. When obtaining a print of a character image using a character signal, the image quality is degraded more by deterioration of the frequency characteristics and waveform of the character signal than by low-level high-frequency noise. Therefore, it is preferable that the noise canceling circuit 30 does not operate in the character signal section, and for this purpose, the switch SW
7 is closed to the A side, and the Jansell circuit 30 in the noise is removed.

The line noise canceling circuit 31 uses the fact that the video signal has line correlation and the fact that noise has no line correlation to remove noise that has no line correlation. This is subtracted from the IH-delayed signal to detect noise with no line correlation.
This detected noise is subtracted from the input signal. For this reason, the character signal that exists only in 1H of the vertical retrace period is simply generated by the Janse circuit 31 in this line noise.
In this case, the line noise canceling circuit 31 may be inserted as is or may be removed. However, character signals that exist over 2H of the vertical retrace period generally have no line correlation. Therefore, in this case, the line noise canceling circuit 31 must be removed. From the above.

In the character signal section, the line noise canceling circuit 31 is removed by closing the switch SW8 to the A side.

The switch SW9 is the switch SW in FIG. 1(a).
3, it is closed to A11l to prevent the noise output from the C carrier color signal processing circuit 38 from being supplied to the mixing circuit 32, but during the period when the color burst signal is present, it is closed to the B side and the mixing circuit 32 is closed. The color burst signal is supplied to the

Since no switch is provided from the BPP 39 to the output terminal 43 to turn off the character signal section, a character signal is obtained at the audio signal output terminal 43 during the character signal section. However, although not shown, the reproduction processing circuit connected to the output terminal 43 includes a mute circuit.
In addition, the FM modulated character signal has a large amplitude and the FM
Since there is a difference of about 1QdB between the audio signal and the audio signal, the text signal section is muted. Therefore, BPF39
and output terminal 43, I! There is no need to provide a switch at #.

Furthermore, since dropout compensation for one character signal section cannot be performed, this compensation operation must be stopped.

For this purpose, the detection level may be made extremely low, or the character signal may be allowed to pass through the dropout compensation circuit 26 as is.

Furthermore, a broadband LPF may be inserted between the FM demodulator 28 and the A side of the switch SW6 to remove noise outside the frequency band of the single character signal.

As described above, wideband character signals can be recorded and reproduced without band limitation, and clear character images can be obtained, and color television signals can also be recorded and reproduced in the same manner as in the prior art.

In the above embodiment, the FM audio signal in the character signal section was prevented from being recorded by the switch SW4 (Fig. In this case, the character signal section FM audio signal and the character signal are mixed and obtained at the audio signal output terminal 43 (in FIG. 1) of the reproduction system, but as explained earlier, the reproduction processing There is no problem because this section is muted by the mute circuit of the circuit.Furthermore, in the playback system, the FM-modulated character signal KFM audio signal is superimposed, but as explained earlier, there is no problem between them. Since there is a difference of about 10 dB, the voice signal does not interfere with the text signal.

Also, when there is no need to record or reproduce character signals,
All you have to do is to forcibly close SWI to SW9 to the B side. This allows recording and reproduction to be performed exactly the same as in the prior art.

Further, the switch control circuit 18 closes the switches SWI to SW9 to the A side between character signals, as described above. This is because if the period during which these switches are closed to the A side is much longer than the character signal section, recording of the FM audio signal will be prohibited by switch SW4 for an unreasonably long period. - The signal reproduction processing circuit either mutes the signal or pre-holds it as a drop alert, significantly deteriorating the sound quality.

FIG. 5 is a circuit diagram showing a specific example of the HPF 7 and switch SW2 in FIG. Resistor, 51, 52.53 is capacitor, 5
4.55 is a coil, and 56.57 is a switching transistor.

In FIG. 5, the input terminal 44 is supplied with the output signal of the FMy&adjuster 6 (FIG. 1(a)), and the input terminal 45 is supplied with a switch pulse from the switch control circuit 18 (FIG. 1(a)). Supplied. Resistance 48. The capacitor 51 and the coil 54 constitute a trap circuit for the low frequency conversion carrier color signal, and the resistor 49. Capacitor 52 and coil A155 are FM
It constitutes a trap circuit for audio signals. variable resistance 50
is used as the adjustment resistance for recording current.

A high-level switch pulse is supplied to the input terminal 45 in periods other than the character signal section. For this purpose, the switched transistors 56 and 57 are turned on, and the trap circuit for the low frequency conversion carrier color signal and the trap circuit for the FM audio signal are inserted. These trap circuits) IPF7t-
It consists of The FM luminance signal from the input terminal 44 is suppressed in the frequency band in which the low frequency conversion carrier color signal and the FMf voice signal are set, and passes through the variable resistor 50 to the output terminal 46.
The signal is supplied from the recording amplifier 8 (FIG. 1(a)).

, In the character signal section, a low-level switch pulse is supplied to the input terminal 45, and the switch transistor 56
．． 57 is turned off. For this reason, the trap circuit for the low frequency conversion carrier color signal and the trap circuit for the FM audio signal are inactive, and the FM converted character signal from the input terminal 44 is 1. Resistance 47. Output terminal 4 through variable resistor 50
6 to a recording amplifier 8.

Although the effect of each trap circuit varies greatly depending on the constants of each element, it is preferable to select the constants of each element as shown in the figure, for example.

FIG. 6 is a circuit diagram showing one specific example of the HPF 23 and SW5 in FIG.

67-69 are capacitors, 70-72 are coils, 73-
76 is a transistor.

In FIG. 6, an input terminal 58 is supplied with a reproduction signal from the preamplifier 22 (FIG. 1 Φ)), and an input terminal 59 is supplied with a switch pulse from the switch control circuit 18 (FIG. 1 Φ)). The capacitor 67 and the coil 70 are the trap capacitor 69 and the coil 72 for the low frequency conversion carrier color signal.
and constitute a trap circuit for the FM audio signal.

The transistor 73 and the resistor 61 constitute an emitter follower, the transistor 4 constitutes an amplifier together with the resistors 63 and 64, and the transistors 75 and 76 are switching transistors.

First, in a period other than the character-signal section, a high-level switch pulse is supplied to the input terminal 59, and the transistor 75.7
6 turns on. As a result, the 7 reproduced signal having the frequency characteristic shown in FIG. After peaking near the carrier, the FM audio signal trap circuit
The audio signal is suppressed. Then, at the output terminal 60! Only the M luminance signal is obtained and supplied to the AGC circuit 24 (FIG. 1(b)).

Next, in the character signal section, a low level switch pulse is supplied to the input terminal 59, and the transistors 75' and 76
is turned off, and the trap circuit for the low frequency conversion carrier color signal and the trap circuit for the FM audio signal are removed. This is H
This is a state in which the PF23 is removed. The reproduced signal having the frequency characteristic shown in FIG.
supplied to

Note that representative examples of constants of each element are illustrated.

Figure 7 shows the noise canceling circuit 30 in Figure 1 Φ).
and a circuit diagram showing a specific example of SW7,
．． 78 is an input terminal, and 79 is an output terminal.

80 is an HPF, 81 is a limiter, and 82 is a subtracter.

83.84 is a resistor, 85.86 is a capacitor, 87 is a switching transistor, and 88 is an inverter.

In FIG. 7, input terminal 77 is connected to switch 5W6 (first
)), and the output terminal 79 is connected to the Jansell circuit 31 during line noise and the A side of the switch SW8 (see Figure 1).
3)). Further, a switch pulse is supplied to the input terminal 78 from the switch control circuit 18 (in FIG. 1), and this switch pulse is inverted by an inverter 88 and supplied to the switching transistor 87. Resistance 83.84. A capacitor 85 constitutes a circuit that attenuates or limits the band of the signal to adjust its level. Capacitor 86 has a very large capacity.

First, in a period other than the character signal section, a high-level switch pulse is supplied to the input terminal 78, and the switching transistor 87 is turned off. In this state, in FIG. 1(b), the switch SW7 is closed to the B side, and the noise canceling circuit 30 is inserted and drawn. A luminance signal from the input terminal 77 having the frequency characteristic indicated by the broken line B in FIG. You get noise. This high frequency noise is level-adjusted by resistors 83, 84 and capacitor 85, and then supplied to subtracter 82. The subtracter 82 subtracts the level-adjusted high-frequency noise from the luminance signal, and a luminance signal from which the low-level high-frequency noise is removed is obtained at the output terminal 79.

In the character signal section, a low level switch pulse is supplied to the input terminal 78, and the switching transistor 87 is turned on. In this state, switch SW7 is shown in Figure 1 [Yes].
is closed to the A side and the noise canceling circuit 30 is removed. When the switching transistor 8) is turned on, a capacitor 86 is inserted between the resistor 83 and the ground terminal,
Since the capacitance of this capacitor 86 is very large, it may be grounded between the resistor 83 and the subtracter 82, which could be dangerous. Therefore, the character signal having the frequency characteristic shown by the solid line A in FIG.

FIG. 8 is a circuit diagram showing a specific example of the line noise canceling circuit 31 and switch SW8 in Q3)' in FIG. 93 is IJ Mitter, 94.9
5 is a subtracter, 96.97 is a resistor, 98°99 is a capacitor, ioo is a switching transistor, and 101 is an inverter.

In FIG. 8, input terminal 89 is connected to switch 5W7 (first
). That is, it is connected to the output terminal 79) in FIG. 7, and the output terminal 91. is the mixing circuit 32 (Fig. 1(b))
It is connected to the. A switch pulse is supplied to the input terminal 90 from the switch control circuit 18 (FIG. 1(b)), and this switch pulse is supplied to the base of the switching transistor 1000 via the inverter 101. Resistors 96 and 97 and capacitor 98 constitute a circuit that attenuates or limits the band of the signal to adjust its level. Capacitor 99 has a very large capacity.

First, in a period other than the character signal section, a high-level switch pulse is supplied to the input terminal 90, and the switching transistor 100 is turned off. In this state (in FIG. 1), the switch SW8 is closed to the B side and the line noise canceling circuit 31 is inserted. A luminance signal having a frequency characteristic indicated by the broken line B in FIG. 3 from the input terminal 89 is sent to the subtracter 94. '95, CCD, etc., is supplied to the IH delay circuit [92. A subtracter 94 subtracts the luminance signal delayed by the IH delay circuit 92 from this luminance signal, and extracts signals and components having no line correlation from the luminance signal. This signal component is supplied to a limiter 93, whereby low level noise without line correlation is obtained. This noise is caused by resistor 96°97 and capacitor 9
8, and is supplied to a subtracter 95, where this noise is subtracted from the luminance signal from the input terminal 89. Therefore, a luminance signal from which noise without line correlation has been removed is obtained at the output terminal 91. −
In the character signal section, a low level switch pulse is supplied to the input terminal 90 1, and the switching transistor 100
is turned on, and a large capacitor 99 is inserted between the resistor 96 and the ground terminal. In this state, switch SW8 is closed to A@ in Figure 1 (b).

This is a state in which the line noise canceling circuit 31 is removed. Therefore, it is grounded between the resistor 96 and the subtracter 95, and the character signal with the frequency characteristic shown by the solid line A in FIG. Supplied.

FIG. 9 is a block diagram showing a recording system of another embodiment of the magnetic recording and reproducing apparatus according to the present invention, in which 102 is an image sensor;
103 is a luminance signal processing circuit, 104 is a low frequency conversion color signal trap circuit, 105 is an FM audio signal trap circuit, 10
6 is a color signal processing circuit.

107 is a switch pulse input terminal, 5WIO-8W16
is a switch, and parts corresponding to those in FIG. 1(a) are given the same reference numerals.

In the previous embodiment, a wideband character signal was superimposed on the vertical retrace period of a color television signal, but in this embodiment shown in FIG. 9, a color television signal of a broadcast program and a video camera are superimposed. It is possible to selectively record and reproduce color television signals from In this case, the video camera can obtain luminance signals and carrier chrominance signals with a wider frequency band than the luminance signals and carrier chrominance signals in the color television signal of the broadcast program, so recording and playback can be performed without loss of these frequency bands. I hope I can
to obtain high-resolution playback images.

First, a case where a color television signal of a broadcast program is recorded with the frequency characteristics shown in FIG. 2 will be described.

In this case, switches 5WIO, 5WII and SW
I6 is closed to the D side, a control signal indicating that an FM audio signal is to be recorded is supplied to the input terminal 107, and the switches SW1.2 to SW1.5W15 are closed to the B side. Color video Shinsho is Switch 5WIO.

After passing through the AGC circuit 2, the Y-shaped filter 3 and the LPF 4 provide a luminance signal in which the carrier color signal is sufficiently suppressed, as described above. This luminance signal is subjected to processing such as emphasis in a processing circuit (not shown) and then modulated by an FM modulator 6. The obtained FM luminance signal is suppressed in the frequency band C (FIG. 2) in which the low-band conversion carrier color signal is set in the low-band conversion carrier color signal trap circuit 104, and is further suppressed in the FM audio signal trap circuit 105. A portion of the frequency band AFM (FIG. 2) in which the FM audio signal is set is suppressed and supplied from the switch SWI 3 to the recording amplifier 8.

Further, a color video signal is supplied from the input terminal 1 to the BPF II, and a carrier color signal is separated. This carrier color signal is
The signal passes through the switch SWI 6 and the ACC circuit 12, and becomes a low frequency converted carrier color signal at the frequency converter 14 and LPF 15. This low frequency converted carrier color signal is suppressed in the frequency band C (FIG. 2) in which the FM audio signal is set by the FM audio signal trap circuit 16, and is supplied to the recording amplifier 8 via the switch SWI 4. .

In this way, the audio signal supplied to the input terminal 19 is processed by the nonlinear circuit 20 and then subjected to FM modulation by the FM modulator 21. The obtained FM audio signal is supplied to the recording amplifier 8 via the switch 5W15.

In the recording amplifier 8, the F'M luminance signal, the low frequency conversion carrier color signal, and the FM audio signal are combined and amplified, and then supplied to the magnetic head 9 and recorded on the magnetic tape 10.

The above recording signal processing is similar to the processing of the luminance signal of the color television signal in FIG. 8g1 diagram (a)
Compatible with HPF7.

Here, if the luminance signal is separated from the color video signal using only the Y-shaped filter 3, if the attenuation of the color subcarrier interleaved in the high frequency range of the luminance signal is insufficient, this luminance signal is FM-modulated. Since the front is emphasized, the remaining subcarrier of the next color interferes with the FM audio signal, causing a buzz in the reproduced audio. For this purpose, an LPF 4 is provided after the Y-shaped filter 3 to further attenuate the carrier color signal remaining in the luminance signal. According to the supplied control signal, 5W12 to SWI 5 are switched to the A side, and the LPF
4. Except for FM audio signal trap circuit 105.16, F
It is possible to relax the restrictions on the frequency band of the M luminance signal and the low-frequency converted carrier color signal and extend the frequency band to within the frequency band in which the FM audio signal is set. This allows the resolution of the reproduced image to be increased.

Incidentally, in this case, the audio signal can be recorded on a linear track with a fixed head, and it is also possible to digitize and compress the time axis, so that so-called oats < lap recording is also possible, so this is not a particular problem.

Next, when recording color television produced by a video camera, switch 5w1o.

Switch to 5WII and 5W16t-C side. In this case, both the luminance signal obtained by the luminance signal processing circuit 103 and the carrier color signal obtained by the chrominance signal processing circuit 1.06 have a wide frequency band. These are mixed to form a color video signal.The luminance signal is sent from the luminance signal processing circuit 103 to the AGC circuit via the switch SWIO, and the carrier color signal is sent from the color signal processing circuit 106 to the switch SW 1.6. via the ACCQ path 12. Since the luminance signal is not interleaved with the carrier color signal, processing by the Y-shaped filter 3 is unnecessary, and the frequency characteristics and waveform of the luminance signal processed thereby are degraded. For this purpose, switch 5
WII is closed to the C side, excluding the Y-shaped filter 3.

When recording and reproducing these luminance signals and carrier color signals as broadband signals, the FM audio signal is not recorded. At this ninth stage, the switches 8W12 to 5w1s are closed to the A side by the control signal supplied to the input filter 107, and as explained earlier, the frequency band of the FM luminance signal and the low-frequency conversion carrier color signal is FMf7! ! Extend the signal to the frequency band to which it is set.

When recording FM audio signals, switch 5W12~
5W15 closes to the B side. In this case, the FM brightness is 1g
Both the color signal and the low-pass converted carrier color signal are recorded as narrowband signals.

As described above, in this embodiment, it is possible to record and reproduce color television signals in which the frequency bands of the luminance signal and the carrier color signal are different, respectively, in critical wave number bands, and to reproduce the signals with high SNR and high resolution. You can get the image.

In addition, in the above embodiment, in addition to the rounding that enables recording and reproduction of the character signal superimposed on the vertical blanking period of the color television signal of the broadcast program, the character signal section and the low frequency conversion carrier color signal trap circuit 104 are added. Needless to say, the output signal of the LPF 15 can be cut off except during the period in which the color nost signal is present.

Furthermore, although a description of the reproduction system of this embodiment will be omitted, for example, the passbands of the luminance signal processing system and the carrier color signal processing system may be switched by detecting the presence or absence of an FM audio signal.

The carrier color signal trap circuit 104.13 in FIG. 9 may have the circuit configuration shown in FIG. 5.

However, the switching transistor 57 is controlled to be turned on or off depending on the presence or absence of the FMf voice signal (ie, the control signal supplied to the input terminal 107 in FIG. 9). The switching transistor 56 is always on, but if character signals are to be recorded over a wide band, the character signal section switching transistor 5 is turned on as described above.
It goes without saying that 6°57 should be turned off.

〔Effect of the invention〕

As explained above, according to the present invention, a color television signal can be recorded and reproduced as a multiplexed signal of a low frequency conversion carrier color signal, an FM audio signal, and a 1i'M luminance signal, as in the prior art. , it is possible to obtain a reproduced image with a high S/N ratio, and also to secure a sufficient recording frequency band for luminance signals with a wide frequency band, making it possible to record and reproduce without impairing that frequency band. It is possible to obtain a clear reproduced image, and it is possible to solve the problems of the above-mentioned prior art and provide a magnetic recording and reproducing device with excellent functions.

[Brief explanation of drawings]

sg1 (a), ·Φ) is a block diagram showing an embodiment of the magnetic recording/reproducing device according to the present invention, FIG. 32 is a characteristic diagram showing the frequency band of the recording signal of the conventional magnetic recording/reproducing device, and FIG.
The figure is a characteristic diagram showing the frequency characteristics of the next character signal superimposed on the color television signal and the frequency characteristics of the reproduced luminance signal in a conventional magnetic recording and reproducing device. Characteristic diagram showing the recording frequency band,
FIG. 5 is a circuit diagram showing a specific example of the high-pass filter of the brightness concealment signal processing system in FIG. 1(a) and the switch at the next stage. Figure 6 is a circuit diagram showing a specific example of a high-pass filter for extracting an FM luminance signal from the reproduced signal in Figure 1 (in Figure 1) and a switch in the next stage, and Figure 7 is a circuit diagram showing a noise canceling circuit in Figure 1 (b). FIG. 8 is a block diagram showing a specific example of the line noise canceling circuit and the switch of m[ in FIG. FIG. 2 is a block diagram showing a recording system of another embodiment of a magnetic recording/reproducing apparatus according to the present invention. 1...Color video signal input terminal, 3...
・Y-shaped filter, 4...Low pass filter, 6...Frequency demodulator, 7...High pass filter, 11... Bandpass filter, 1
4... Frequency converter. 15...Low pass filter, 16...
Frequency modulation audio signal trap circuit, 17... Synchronization separation circuit. 18...Switch control circuit, 19...
Audio signal input terminal, 21... Frequency modulator, 2
3... High pass filter, 28... Frequency demodulator, 29... Low pass filter, 32
...Mixing circuit, 33...Color video signal output terminal, 34...Low pass filter, 35
... Frequency converter, 36. 39 ... Curved band pass filter, 41 ... Frequency demodulator, 43.
...Audio signal output terminal, 102...Photography g
R Yuko. 103... Luminance signal processing circuit, 104...
...Low frequency conversion carrier color signal trap circuit, 105...
... Frequency and wave number modulation audio signal trap circuit, 106...
...Color signal processing circuit, S'WI~5W16...
·switch. Number of laps (MHz) Frequency '4! i (MHz)

Claims (2)

[Claims] (1) Separate a color television signal into a brightness signal, a carrier color signal, and an audio signal, the brightness signal being angularly modulated to the high frequency side, and the carrier color signal being low frequency converted to the low frequency side. At the same time, the audio signal is frequency-modulated and its frequency band is set between the frequency band of the angle-modulated luminance signal and the frequency band of the low-band-converted carrier color signal for recording and reproduction. In the magnetic recording and reproducing device, when the frequency band of the luminance signal is narrow, recording and reproducing is possible by combining the low frequency-converted carrier color signal, the frequency-modulated audio signal, and the angle-modulated luminance signal, and a first means for prohibiting recording of at least the frequency modulated audio signal when the frequency band of the luminance signal is wide; and a first means for prohibiting recording of the frequency modulated audio signal when the frequency band of the luminance signal is wide; and a second means for extending at least the recording frequency band to which the frequency-modulated audio signal is to be set, so that the luminance signal having a wide frequency band can be recorded and reproduced over the entire required frequency band. A magnetic recording/reproducing device characterized by: (2) A magnetic recording device according to claim (1), wherein the first means is capable of prohibiting recording of the low-frequency converted carrier color signal except for a color burst signal. playback device.