KR790001026B1 - Regenerative apparatus for color image signal - Google Patents

Abstract

In a method for increasing record density by recording a color image signal on the magnetic tape, the output of the filter is supplied to the frequency converter(28) in order to regenerate a color image signal. The carrier wave of the frequency (1st fA) is supplied to an inverter amplifier(45), and the output is transfered to a switch circuit(46). The burst signal of a color carrier signal is phase detected, and the transfer state controlled by the detected output.

Description

Apparatus for reproducing color image signals

1 to 9 illustrate a special recording and reproducing method of a color video signal.

1 is a view showing a rotating magnetic head device.

2 is a view showing a state of magnetic voids of a rotating magnetic head.

3 shows a recording pattern on a tape.

4 is a schematic diagram of a recorder.

5 is a schematic diagram of a regeneration system.

6 shows a frequency spectrum for explanation thereof.

7 is a schematic diagram of a portion of the device.

8 and 9 are waveform diagrams for explanation.

10 is a schematic diagram of an example of the apparatus of the present invention.

11 is a waveform diagram for explanation thereof.

12 is a view for explaining another example of the present invention.

Figure 13 is a schematic diagram of another example of the apparatus of the present invention.

14 is a waveform diagram for explanation thereof.

Fig. 15 is a schematic diagram showing another example of a part of the apparatus of the present invention.

When recording a color video signal on a magnetic tape or the like, the recording density can be greatly increased by the following method.

That is, when recording on a magnetic tape, as shown in FIG. 1, two rotating magnetic heads H _A and H _B are attached at 180 ° intervals to guide the tape 1 to the tape. The drum 2 is driven along the inclination over an angle range of approximately 180 degrees, but as shown in FIG. 2, the arrows of the gaps g _A and g _B of the heads H _A and H _B are shown. The inclination angle with respect to the scanning direction shown by (3) is made different. Then, the heads H _A and H _B are rotated once in one frame, for example, to form tracks T _A and T _B alternately every head as head H _A and H _B as shown in FIG. 3.

In this case, in recording, as shown in FIG. 4, the color image signal from the input terminal 11 is supplied to the low pass filter 12 to obtain a luminance signal, which is supplied to the frequency modulator 13 to record and reproduce. A modulated luminance signal that occupies the high frequency side of the possible frequency band is obtained and supplied to the synthesizer 14. The input color video signal is further supplied to the band pass filter 15 to extract the carrier color signal C _S having a frequency of subcarrier f _s , and supplied to the frequency converter 16 to supply to the low frequency side, that is, the subcarrier. The frequency is converted so that the frequency is f _A , and the signal C _A is supplied to the inverting amplifier 17. Thus, C _A from the (+) output terminal of the inverting _amp 17 is supplied to one input terminal of the switch circuit 18, so that the signal C _A from the (-) output terminal of the _amp 17 is transferred to the switch arc 18 To the other end of the input. Thus, the switch circuit 18 is changed to the state of the drawing in the section where the head H _A forms the track T _A by the switching signal S _C , for example, in the odd feed, and the head H _B forms the track T _B. In sections to be made, for example, the rainy season, the state is alternated from one state to another in the state opposite to the state of the state and the state of the state. The output of the switch circuit 18 is supplied to the synthesizer 14, synthesized with the modulated luminance signal, and the synthesized output is supplied to the heads H _A and H _B through the amps 19.

In this way, the signal C _{A in} which the frequency of the subcarrier is f _A and the phase is constant is recorded in the track T _A as a carrier color signal. On the other hand, the switch circuit 18 alternately extracts the signal C _A having the frequency of the subcarrier at f _A and the phase thereof and the signal C _A phase-inverted with respect to the signal C every one horizontal section. It is equivalent to combining a square wave signal having a relatively "f1" value and a "-1" value for each horizontal section alternately, and this means that the signal C _A is the frequency of the horizontal frequency f _H. only an equilibrium modulated as a square wave signal of ½, and thus the track T _B, the transfer color signal C _B in which the carrier frequency f _B as a stray ½f _H is written with respect to the _a f.

In other words, the carrier color signals C _A and C _B having a relationship of frequency interleaving with each other are recorded in the tracks T _A and T _B adjacent to each other.

In the reproduction, as shown in FIG. 5, the reproduction outputs from the heads H _A and H _B are supplied to the high pass filter 21 through the reproduction amplifier 20 to extract the modulated luminance signal, and this is applied to the limiter ( The demodulator 23 is supplied to the demodulator 23 through 22, and the demodulated luminance signal is supplied to the synthesizer 24. In the above recording, as shown in FIG. 3, even when a so-called guard band is not provided between adjacent tracks T _A and T _B , the modulated luminance signal is a high frequency signal, so that the head H _A is T _A. when injected with this track scanning a portion of the T _B, and further when the head H _B scans the track T _B this is also to scan a portion of the track T _a, cross-torque does not occur, the synthesizer 24 is provided with a cross A torque signal without torque is supplied.

The reproduction outputs from the heads H _A and H _B are further supplied to the regional passage filter 25 to extract the reproduction carrier color signal. In the recording, by in between the tracks T _A and T _B which are adjacent to each other as described above do not place the ego de band, the head H _A is when injected this part of the track T _B to scan the tracks T _A case of the output of the filter 25, Figure 6, as shown in C, which the frequency interleaving eve bar with respect to the signal C _a is that the signal C _B in relation mixed as a cross-torque component, and the head H _B Scans track T _B when it scans a portion of track T _A , the output of filter 25 at this time is of frequency interleaved with this for signal C _B as shown in FIG. The signal C _A is mixed as a crosstalk component. The output of the filter 25 is supplied to the inverting amplifier 26, the signal obtained at the (+) side output terminal is supplied to one input terminal of the switch circuit 27, and the signal obtained at the (-) side output terminal is switched. In the section where the head H _A should scan the track T _A , like the switch circuit 18 at the time of recording, by supplying the switch circuit 27 to the other input terminal of the circuit 27 by the switching signal S _C. In the section in which the head H _B should scan the track T _B , the switch is alternated to the state of FIG. Therefore, the head H _A is the track starting with T period, the switch circuit 27 for scanning the _A, signal C _B to the signal C _A of the (+) through the side output end of Amphoe 26, the obtained is mixed as a cross torque Lose. On the other hand, the head H _B the track section to scan the T _B, starting with a filter 25, the signal C _A to the signal C _B as described above, but the is obtained mixture as a cross-torque component signal C _B is, signal C _A and signal C _a 1 as will for every horizontal period repeated Gogh, of the head H _B, the track T interval of, any interval of the horizontal section Guan in Amphoe 26 from the switching circuit 27 for scanning the _B (+) in the side becomes the output signal C _a to the signal C _a via is obtained is mixed as a cross-torque component, the horizontal leg of the adjacent one interval, the beginning to the switch circuit 27, Amphoe 26 (-) The signal C _A is obtained by mixing the signal C _A as a crosstalk component through the side output terminal. Consequently, even in the section in which the head H _B scans the track T _B , the signal C _{A is} output from the switch circuit 27. the signal C _B to obtain a mixed composition as a cross torque It will lose. Therefore, when the output of the switch circuit 27 is supplied to the frequency converter 28 and frequency-converted as a wave having a frequency of f _S + f _A , the frequency converter 29 is shown in Figs. As described above, a mixture of crosstalk components having a frequency interleaving relationship with the signals C _SA and C _SB from a predetermined track whose frequencies of subcarriers are the original frequency f _S is obtained. Therefore, when the output of this frequency converter 28 is supplied to the C-shaped comb filter 29, as shown in FIG. 6G, the crosstalk component is removed and the original carrier color signal C _S is obtained. This transfer color signal C _S is supplied to the combiner 24 and synthesized with the luminance signal.

Therefore, the output terminal 30 obtains a reproduction color video signal without crosstalk.

In this case, as shown in FIG. 7, the switching signal S _C is a pulse S _PG (FIG. 8 A) from the pulse generator 31 for detecting the rotation angle positions of the heads H _A and H _B. It is supplied to the stable multivibrator 32, and the head H _A becomes " O ", for example, as odd radix V _O which scans the tape 1, and the head H _B scans the tape 1, for example, The square V _E obtains the square wave signal S _V (Fig. 8B), which becomes " 1 ", while the horizontal synchronizing signal P _H is supplied to the flip-flop circuit 33 to obtain the signal S _H which is inverted every one horizontal section. This signal can be obtained by supplying the signals S _V and S _H to the AND gate circuit 34.

In this case, however, the flip-flop circuit 33 may be reversed as shown in FIG. 8C in the section in which the head H _B scans on the tape 1, and may be reversed in the opposite state to this. . At the time of reproduction, in a section in which the head H _B scans on the tape 1, the flip-flop circuit 33 inverts as shown in FIG. 8C to obtain a switching signal S _C as shown in FIG. In the case where 27) is switched in response to this, as the output of the filter 25, as shown in FIG. 9A, the signals C _A and C _A continue alternately every horizontal section of the switch circuit 27. As an output, if the signal C _A is continuous as shown in Fig. B, if the flip-flop circuit 33 inverts to the state opposite to that of Fig. 8C, the switching signal S _C equal to the Fig. E is When the switch circuit 27 is switched in response to this, as the output of the switch circuit 27, as shown in FIG. 9C, the signal C _A is continuous. That is, in this case, as apparent in FIG. 9C, the carrier color signal obtained from the switch circuit 27 has the phase of the subcarrier every time the reproduction output from the heads H _A and H _B is switched, i.e., every feed. This is reversed.

Therefore, in the reproduction of color reproduction signals, an automatic phase adjustment circuit so-called APC circuit for controlling the frequency of the carrier for frequency conversion by the burst signal in the reproduction carrier color signal is usually provided. Also in this case, since the APC circuit is provided in the reproduction system, the reproduction carrier color signal is obtained as the output of the frequency converter 28, and therefore the comb filter 29, as if the phase of the subcarrier becomes a predetermined constant phase. In this case, however, when the regeneration output from the heads H _A and H _B is switched and the phase of the subcarrier of the reproduction carrier color signal from the switch circuit 27 is reversed, the APC operation is performed by the APC circuit. phase control does not follow immediately to this, because the conveying color signal supplied to the synthesizer 24, the reproduction output from the heads H _a and H _B are switched In the immediately following, that is, that the color burst in the beginning of the blood flowing to the yield.

In view of the above, the present invention takes the above-mentioned special recording and reproducing method. As to ensure that a color video signal of regular color is obtained, an example of the apparatus of the present invention will be described below with reference to FIG. In the present invention, the phase detection of the burrs signal in the carrier color signal obtained by the frequency conversion circuit is detected, and the switching state of the switch circuit constituting the frequency conversion circuit is controlled by the detection output.

In the example of FIG. 10, reference numeral 35 denotes a frequency converter circuit, which is constituted as the inverting amplifier 26, the switch circuit 27, and the frequency converter 27 as described above.

Reference numeral 36 denotes the above-described APC circuit, which transmits a reference carrier of a frequency f _S from the reference oscillator 37 and an oscillation output of frequency f _A from the variable frequency oscillator 38 to the frequency converter 39. The carrier is supplied to obtain a carrier for frequency conversion having a frequency f _S + f _A , and is supplied to the frequency converter 28, but the reproduction carrier color signal from the frequency converter 28 is supplied to the burst gate circuit 40. Extracts the burst signal, supplies it to the phase detection circuit 41, supplies the reference carrier from the reference oscillator 37 to the circuit 41, and outputs the detection output of the circuit 41 to the variable frequency oscillator ( 38) to control the oscillation frequency, and thus the frequency of the carrier for frequency conversion supplied to the frequency converter 28.

Thus, apart from the phase detection circuit 41 of this APC circuit 36, the phase detection circuit 42

Is provided, and the burst signal from the burst gate circuit 40 is supplied to the phase detection circuit 42, while the reference carrier from the reference oscillator 37 is supplied with an appropriate abnormal amount. The circuit 43 is supplied to the circuit 42 via the circuit 43, and the phase detection output from the circuit 42 is supplied to the flip-roll circuit 33 to perform the inversion operation, that is, the switching circuit 27. Control the switching state.

In this case, when the signal C _A is obtained from the switch circuit 27, and thus the signal C _S is obtained from the frequency converter 28, the burst signal supplied to the phase detection circuit 42 and the reference carrier are in phase. phase detection output is in part (負), opposed to the signal C _a from the switch circuit 27 it is obtained, and thus a frequency converter 28, the sub-carrier with respect to the signal C _S from the phase shift signal C _S is obtained been At this time, the burst signal supplied to the phase detection circuit 42 and the reference carrier are inverted phase, and the phase detection output becomes positive, and when this positive detection output is obtained, the flip-flop circuit Let (33) reverse this.

Thus, the head H, the track T _B in the filter 25 when playing back a signal to the excellent blood Ile V _E at _B, the 11 degrees as shown in B, signal C _A, C signal _A, signal C _A, ... The carrier color signal is successively obtained, and the flip-flop circuit 33 tries to invert as in the same degree C, and the switch circuit 27 is opposite to the state of the figure in the horizontal section in which the signal C _A is obtained from the filter 25. In the horizontal section where the signal C _A is switched to the state where the signal C _A is obtained by the filter 25, the switch circuit 27 tries to obtain the signal C _A continuously as shown in the diagram D in the diagram. .

However, at this time, at the time t ₁ at which the first burst signal of the feed V _W is obtained, as described above, the positive detection output D + is obtained in the phase detection circuit 42 as shown in FIG. As the flip-flop circuit 33 shows in Fig. E, the flip-flop circuit 33 is inverted at the time t ₁ and the inverted state of the flip-flop circuit 33 is changed. Therefore, the switch circuit 27 is then switched to the state of FIG. In the horizontal section where the signal C _A is obtained by the filter 25, and to the state opposite to the state of the diagram in the horizontal section where the signal C _A is obtained from the filter 25. In the switch circuit 27, the signal C _A is continuously obtained as shown in FIG. In this state, since the negative detection output D- is obtained in the phase detection circuit 42 as shown in FIG. 2 as described above, the flip-flop circuit 33 is not inverted by the burst signal. The same applies to the case where the inverted state of the flip-flop circuit 33 is thus reversed to the desired state in the middle of the feed V _E , and thus the switching state of the switch circuit 27 is for some reason.

Therefore, eventually, from the switch circuit 27, a carrier color signal C _A having a constant phase of the subcarrier is always obtained, and therefore, the comb filter 29 always obtains a carrier color signal C _S of a predetermined color. Even if the color is wrong, it is not a problem because it is only one horizontal section.

By the way, in the above case, although the cross-talk component was ignored, the cross-talk component was mixed in the output of the switch circuit 27 and therefore the output of the frequency converter 28 as described in the introduction. . Thus, if the burst signal in the carrier color signal from the predetermined track and the burst signal in the carrier color signal as the cross-orthogonal component from the neighboring tracks are obtained at the same time, the former level is sufficiently larger than the latter level. For example, even if both phases are reversed, the burst signal obtained by the burst gate circuit 40 is in the same phase as the burst signal in the carrier color signal in a predetermined track, and there is no problem. However, in the track T _A and T _B to the recording position T _H of the horizontal synchronizing signal P _H neighbor, 12 even if either, is twisted, as shown in A, and the conveying burr host signal of color sinhojung in a given track When a burst signal in a carrier color signal as a cross torque component in a neighboring track is obtained at the wrong time, a problem arises.

That is, in this case, the head H _B is the track when playing T _B, the filter 25 tracks T carrying a color signal burr host signal in the C _B from _B, and 12 Fig. A B, B, obtained from B, B,… As shown in the figure, the phase inversion is alternately performed, but the output of the switch circuit 27, and therefore the burst gate circuit 40, is of constant phase. As described above, the phase detection circuit 42 starts from the twelfth phase. As shown in FIG. B, a negative detection output D- is obtained, while the bias signal in the carrier color signal C _A as a cross torque component from the neighboring track T _A obtained by the filter 25 is shown in FIG. In A, B, B, B,... As shown in FIG. 2, the output of the switch circuit 27 and therefore the burst gate circuit 40 is alternately inverted in phase. From the phase detection circuit 42, as shown in FIG. Similarly, later, for example, of the negative detection output D-, the negative detection output E- and the positive detection output E _t are obtained. Thus, if the level of the cross torque component is sufficiently small, there is no problem, but the level of the cross torque component is relatively large, so that the voltage sufficient to trigger the flip-flop circuit 33 in which the positive detection output E _t is indicated by the diagonal line of FIG. If this is the case, the flip-flop circuit 33 is inverted by this, and the switching state of the switch circuit 27 is reversed from the desired state, and the carrier color signal obtained by the filter 29 is described above. Until the switching state of the switch circuit 27 is corrected by the control, it is not in a normal phase.

In the following example of the present invention, even such a defect is eliminated, and the burst signal in the carrier color signal obtained by the comb filter 29 is phase detected, and the switching output of the switch circuit 27 is detected by the detection output. To control.

That is, as shown in FIG. 13, the output of the comb filter 29 is supplied to the burst gate circuit 40. As shown in FIG. Otherwise, it is the same as the example of FIG.

In this case, since the comb filter 29 does not obtain the carrier color signal as the crosstalk component in the neighboring track as described earlier, the burst as the crosstalk component from the burst gate circuit 40 is obtained. The signal is not obtained, and therefore, in the phase detection circuit 42, only the phase detection output of the burst signal in the carrier color signal in the track is obtained, and there is no inconvenience as described in FIG.

In this case, however, when the switching state of the switch circuit 27 is not appropriate, the aspect of the carrier color signal obtained by the filter 29 is slightly different from the case of the example of FIG.

That is, when the head H _B reproduces the signal of the field V _B superior to the track T _B , as shown in Fig. 14A, the inverted state of the flip-flop circuit 33, and therefore the switching state of the switch circuit 27, is appropriate. Otherwise, in the switch circuit 27 and hence the comb filter 29, the time t. At which the first burst signal of the feed V _E is obtained is obtained. _In the phase detection circuit 42 at ₁ , the positive detection output D ₊ is obtained as shown in the same figure G. As shown in the figure H, the flip-flop circuit 33 is inverted and the switching of the switch circuit 27 is performed. It is the same as the example of FIG. 10 that a state becomes appropriate.

Therefore, from the switch circuit 27, as shown in FIG. 14D, the signal C _A having a constant phase of the subcarrier is obtained continuously except for the first burst signal. In the frequency converter 28, the same signal is obtained. Although C _S is obtained, the comb filter 29 combines this and the signal shown in the same degree E which is one horizontal period later, so that the first burst signal from the filter 29 as shown in the same degree F is finally obtained. The color is different in the horizontal section where? Is obtained, and the signal disappears in the subsequent horizontal section. However, the carrier color signal of the normal color is obtained in the other section. The same applies to the case where the inverted state of the flip-flop circuit 33 is thus changed in the middle of the feed V _E , so that the switching state of the switch circuit 27 is reversed to the desired state.

In the same manner as described above, instead of supplying the carrier color signal to the inverting amplifier and switching the output thereof, the recording is performed as described above even if the phase of the wave for frequency conversion is inverted. The present invention can be applied to such a case because regeneration is possible. That is, in this case, as shown in FIG. 15, the output of the filter 15 is supplied to the frequency converter 16 at the time of recording, and the output of the filter 15 is supplied to the synthesizer 14 at the time of recording. The output of 25) is supplied directly to the frequency converter 28, and the output thereof is supplied to the synthesizer 24 through the comb filter 29, which is obtained at the reference oscillator at the time of recording. At the time of reproduction, a carrier wave having a frequency f _S + f _A obtained by the frequency converter 39 is supplied to the inverting amplifier 45, and the output is switched as the switch circuit 46. Thus, during regeneration, the burst signal in the carrier color signal obtained by the frequency converter 28 or the comb filter 29 is phase-detected, and the switching state of the switch circuit 46 is controlled as described above as the detection output. do.

In the case of the PAL color video signal, the switch circuit 27 or 46 may be switched every two horizontal sections in the section in which the head HB forms or scans the track TB. Applicable

Claims (1)

As shown in the figure, as described above in the main text, the carrier color signal is recorded in one interval of tracks with the subcarriers in a constant phase, and in the track of one interval, the carrier color signal is stored in the subcarriers. In a recording medium recorded in a phase-inverted state every integer horizontal section, in reproducing a color video signal, a frequency-converted reproduction carrier color signal is converted so that a subcarrier becomes a constant phase in a section corresponding to the track of one interval. And a frequency conversion circuit for frequency converting the subcarriers into a constant phase by switching the switch circuit every integer horizontal section in a section corresponding to the tracks of the remaining intervals. A comb-shaped filter supplied with a carrier color signal of The reproducing apparatus of the color image signal made such that the switching state of the switching circuit controlled by the detection output signal of the burr host conveying color sinhojung and phase detection,.

Images