JPH0113271B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a delay time control signal generation circuit during variable speed playback, and in particular, the recording positions of synchronization signals of adjacent tracks are shifted from each other in the track longitudinal direction (not aligned in the track width direction). ) The present invention relates to a delay time control signal generating circuit that can stably control the delay time of a delay circuit that delays a reproduced signal when reproducing a magnetic tape having a track pattern at a tape running speed different from that during recording. Prior Art Magnetic recording and reproducing devices (VTRs) using the azimuth recording and reproducing method have been widely known, but in the standard mode, the recording positions of horizontal synchronizing signals of adjacent tracks are aligned in the track width direction. In other words, they are usually recorded side by side in the longitudinal direction of the track (so-called H-line recording). Therefore, for example, when recording a PAL color video signal, the track pattern is
The result will be as shown in Figure A. In the figure A, the numbers indicate the horizontal scanning line number and the video signal recording section of the 1H (H is the horizontal scanning period) section of the horizontal scanning line number. Here, as is well known, the carrier color signal of the PAL system is
This is a modulated wave obtained by performing carrier suppression quadrature two-phase amplitude modulation on a color subcarrier of a predetermined frequency using two color difference signals R-Y and B-Y. Only the color subcarrier of the
The phase is inverted each time. Therefore, in FIG. 1A, among the recording conveyance color signals, the phase of the first color subcarrier modulated by the color difference signal RY is the color difference signal B−
The 1H recording section that differs by -90° from the phase of the second color subcarrier modulated by Y (the first color subcarrier has a phase inversion) is shown with diagonal lines, and +
1H recording sections that differ by 90° are shown without diagonal lines (see Figures 2A, 18A, and 19A below).
(same as well). Note that, as will be described later, the carrier color signal is converted to a low frequency and recorded. Further, F1 and F2 are video signal recording tracks of the first and second frames, and the tracks are recorded and formed sequentially from left to right in FIG. signal is recorded). As can be seen from FIG. 1A, the recording track pattern in the above standard mode is such that the respective track recording start positions of two adjacent tracks are different from each other.
There is a deviation of 1.5H, so that the horizontal synchronization signal recording positions of adjacent tracks are aligned in the track width direction, and the color subcarrier modulated by the color difference signal R-Y is a modulated wave whose phase is inverted. These are recorded in alignment with each other in the track width direction. However, in recent years, the recording and playback time of VTRs has tended to become longer, and for this reason, the track width of the rotating head can be changed without changing the tape length, drum diameter, video signal recording length of one track, etc. If you narrow the magnetic tape and reduce the tape running speed of the magnetic tape to, for example, 1/2 of that in the standard mode to obtain twice the recording time as in the standard mode, the recording time of two adjacent tracks will be reduced. Since the deviation between the respective track recording start positions is 0.75H, the recording track pattern becomes a track pattern in which H is not arranged as shown in FIG. 2A. Therefore, in the recording track pattern in the so-called long-time mode, the 1H recording sections in which the color subcarriers modulated by the color difference signal RY in adjacent tracks are inverted in phase are also recorded with a shift from each other. It turns out. Whether or not such recording track patterns are recorded in H alignment can be determined by, in particular, reproducing the recorded signal by setting the running speed of the magnetic tape to a value different from that at the time of recording.
This becomes a serious problem during so-called variable speed playback (or special playback). In other words, during variable speed playback, the magnetic tape is run at a different speed than when recording.
The scanning locus of the rotary head crosses multiple tracks, so that in addition to the tracks recorded by the rotary head with the same azimuth angle as the rotary head used for reproduction, the tracks recorded with the rotary head with a different azimuth angle ( The so-called reverse track will also be scanned. During variable speed playback of a magnetic tape recorded in the standard mode and having a track pattern recorded in an H arrangement as shown in FIG. 1A, one rotating head draws a scanning locus as shown by SS in FIG. Assuming that the head reproduction signal is
It will look like this. In FIGS. 1A and 1B, when the tape sliding area of the rotary head is mostly occupied by the reverse track (horizontal scanning line number ``4'' in the first frame F1 and horizontal scanning line number ``14'' in the second frame
(near the 1H period), the FM playback level drops significantly due to the azimuth loss effect, causing noise bars on the playback screen, but as shown in Figure 1B, the horizontal synchronization signal is always played back at 1H intervals. , and since the color difference signal R-Y is reproduced alternately between the 1H interval in which the carrier wave is phase inverted and the 1H interval in which the carrier wave is not phase inverted, regarding the periodicity of the reproduced horizontal synchronization signal and the order of the reproduced carrier color signal, records PAL
The system is the same as the color video signal, so there is no problem. On the other hand, on a magnetic tape recorded in a long-time mode and having an H-aligned and unrecorded track pattern as shown in FIG. When variable speed playback is performed by drawing the tape, the head playback signal becomes as schematically shown in Figure 2B, and when the tape sliding area of the rotating head is mostly occupied by reverse tracks (horizontal scanning line (e.g. between "4" in the first frame and "7" in the second frame, between "14" in the second frame and "17" in the third frame, etc.), and the playback The interval between the horizontal synchronizing signals becomes 1/2H, and the order of the reproduced carrier color signals is further disrupted. For this reason, during variable speed playback of a magnetic tape having a track pattern that is not recorded in H alignment, the periodicity of the playback horizontal synchronizing signal is disturbed when the rotating head crosses the reverse track, so the playback signal is directly transferred to the FM.
When demodulated and supplied to a monitor display device, horizontal image shift (so-called skew phenomenon) occurs and color fading occurs, resulting in extremely poor quality reproduced images. Conventionally, therefore, the occurrence of the above-mentioned skew phenomenon and color fading has been prevented by a correction device having a block system diagram shown in FIG. In FIG. 3, previously recorded signals on a magnetic tape having a track pattern as shown in FIG. Terminal 5a of circuit 5,
5b respectively. The switch circuit 5 detects the rotational phase of a rotating body (such as a rotating drum) on which the rotating heads 1 and 2 are mounted facing each other by a known means, and receives a rotational phase detection pulse of one field period. By being applied as a switching pulse from the input terminal 6, it is switched and connected to the terminal side of the head that is outputting the reproduced signal, and the reproduced signal is sent to the FM demodulation circuit 7 via the terminal 5c.
and are selectively output to the color signal processing circuit 8, respectively. Here, on the magnetic tape, the PAL color video signal is separated into a luminance signal and a carrier color signal, the luminance signal is frequency modulated (FM), and the carrier color signal is below the frequency band of this FM luminance signal. The frequency is converted to an unoccupied band to produce a low frequency converted carrier color signal, and a signal obtained by mixing and multiplexing these two signals is recorded. Therefore, the reproduced luminance signal is taken out from the FM demodulation circuit 7 and supplied to the next stage luminance signal processing circuit 9, where it is subjected to predetermined signal processing such as dropout compensation and de-emphasis. On the other hand, the color signal processing circuit 8 selects the frequency of the low-frequency converted carrier color signal in the input reproduction signal, returns it to the original frequency band by frequency conversion, and performs correction processing to prevent crosstalk from adjacent tracks, etc. The reproduced carrier color signals obtained by performing the above are supplied to the terminals 11b of the 1H delay circuit 10 and the switch circuit 11, respectively. The switch circuit 11 receives the output delayed reproduction carrier color signal of the 1H delay circuit 10 which enters the terminal 11a and the terminal 11b.
The incoming non-delayed reproduction conveyance color signals from the color signal processing circuit 8 are selectively outputted via the terminal 11c in response to a signal from the color order judgment circuit 18, which will be described later, and supplied to the mixing circuit 12. to mix it with the reproduced luminance signal. The reproduced color video signal mixed and taken out by the mixing circuit 12 is supplied to the terminal 14a of the switch circuit 14 through the 1/2H delay circuit 13, and is directly supplied to the switch circuit 14 without being delayed.
is supplied to terminal 14b of. The reproduced luminance signal outputted from the luminance signal processing circuit 9 is also supplied to the 1/2H skew detection circuit 15, where the horizontal synchronization signal in the reproduced luminance signal does not have the correct period. The skewed part is detected. The detection signal of the detection circuit 15 is supplied as a switching signal to the switch circuit 14, and when the above-mentioned 1/2H skew occurs, the terminals 14a and 14b which were previously connected are switched to the other terminal. In this way, the periodicity of the reproduced horizontal synchronizing signal is ensured, and the terminal 14 of the switch circuit 14
The reproduced color video signal taken out from c is output to an output terminal 19, and is also supplied to a color burst extraction circuit 16 to extract the color burst signal, and then subjected to phase detection by a phase detection circuit 17. As a result, if the arrangement order (color order) of the reproduced carrier color signals is correct, the phase detection circuit 17
A square wave that is inverted every 1H is extracted,
If the color order is incorrect, the periodicity of the output signal of the phase detection circuit 17 will be disturbed. The color order determining circuit 18 determines whether the color order is disordered from this periodicity disorder, and when it detects that the color order is disordered, the switch circuit 11 is connected to the terminals 11a and 11b that have been connected up to that point. The connection will be switched from one terminal to the other. As a result, reproduced conveyance color signals in the correct color order are always taken out from the terminal 11c of the switch circuit 11. In this way, the output terminal 19 receives a variable speed reproduced color video signal in the correct color order and in which the periodicity of the horizontal synchronization signal is maintained. Problems to be Solved by the Invention However, the above-mentioned conventional device controls the delay time of the reproduced color video signal with a 1/2H delay or no delay, and controls the color order using the detection output signal from the 1/2H skew detection circuit 15. The judgment output signal from the judgment circuit 18 is used to control the delay time of the reproduced carrier color signal with a 1H delay or no delay, but complex analog signal processing is required to control the delay time, and analog Since the signal processing circuit portion was large, it was difficult to implement it into an IC or microprocessor. In addition, one rotary head for the standard mode and one rotary head for the long-term mode are placed very close to each other,
If the noise bars that occur during reverse track scanning during variable speed playback are significantly reduced by selecting these heads appropriately during variable speed playback, a skew of 0.25H will occur as will be explained in detail later. , to reduce this skew
Although 0.25H skew detection is required, it has been difficult to stably perform 0.25H skew detection using the analog signal processing described above. Therefore, in a patent application filed on the same date as the present application (title of the invention: "Delay time control device during variable speed reproduction"), the inventor proposed that the level difference between the reproduction signals of two rotary heads having different azimuth angle gaps. Based on this, we have proposed a delay time control device that solves the above problems by controlling the delay time of the reproduced signal during variable speed reproduction. However, in this proposed delay time control device, if the comparison output signals of the levels of the reproduced frequency modulated wave signals of the two rotating heads are used as they are as control signals for delay time control,
In reality, since the sliding condition between the head and the tape is unstable, erroneously detected pulses are mixed into the above comparison output signal, making stable and accurate delay time control impossible. It was hot. Therefore, the present invention provides a delay time during variable speed reproduction in which a control signal for delay time control is generated based on a signal in which the non-periodic pulse portion of the comparison output signal containing the above-mentioned erroneously detected pulses is ignored as noise. An object of the present invention is to provide a control signal generation circuit. Means for Solving the Problems The present invention provides a variable delay circuit that is supplied to a variable delay circuit that delays a reproduced video signal, and controls the delay time so that at least a horizontal synchronization signal in the reproduced video signal is reproduced at a regular constant cycle. a control signal generation circuit, the circuit comprising: a first comparing means for comparing levels of reproduced frequency modulated wave signals of the two rotary heads of the set; and an output signal of the first comparing means; an integrating circuit; a first signal generating circuit to which the output signal of the integrating circuit is supplied and outputting a signal synchronized with a frequency component related to the number of times the recorded tracks of the set of two rotary heads are traversed; a second comparing means for comparing the levels of the output signal of the first signal generating circuit and a reference voltage, and a second signal generating means for generating and outputting the delay control signal based on the output signal of the second comparing means. It is composed of a circuit and
One embodiment will be described below with reference to the drawings. Embodiment FIG. 4 shows an embodiment of the head arrangement of a recording/reproducing apparatus to which the circuit of the present invention can be applied. In the figure, rotary heads H _S1 and H _S2 having a first head gap for standard mode, for example, are fixedly attached to a rotary body 21 such as a rotary drum at equal angular intervals of 180°.
The rotating heads H _S1 and H _S2 have different azimuth angles from each other. Also, the rotating body 21
The rotary heads H _L2 , H _L2 for long-time mode have a second head gap at a position preceding the rotary heads H S1 , H _S2 by a certain distance in the direction of rotation.
H _L1 are installed and fixed respectively. This rotating body 21
is rotated in the _X1 direction at, for example, 1500 rpm,
Further, the magnetic tape 23 is guided by guide poles 22a and 22b and is wound in a spliced manner over an angular range of over 180 degrees. The magnetic tape 23 is held and driven by a capstan and a pinch roller (not shown) and is made to run in the direction of arrow _X2 at a speed of one track pitch during recording and normal playback, during which the rotating body 21 makes half a rotation. FIG. 5 shows an embodiment of the mounting height positional relationship of each rotary head of a recording/reproducing apparatus to which the circuit of the present invention can be applied. In FIG. 5, the same rotating heads as in FIG. 4 are given the same reference numerals. Rotating head above
The track width of H _S1 and H _S2 is 46 μm, and the track width of rotating heads H _L1 and H _L2 is selected to be 32 μm. The rotating heads H _S1 and H _L1 each have the same first azimuth angle gap;
The rotating heads H _S2 and H _L2 each have the same second azimuth angle gap. As can be seen from FIG. 5, the above-mentioned first azimuth angle and second azimuth angle are angles in which one is positive and the other is negative with respect to the track width direction of the head. Further, the rotary head H _L1 is spaced from the rotary head H _S2 in the rotation direction by a distance corresponding to, for example, the recording length of one horizontal scanning period (1H) on the magnetic tape 23. When recording and reproducing signals, it is installed 310 μm in advance. Similarly, the rotary head H _L2 is mounted ahead of the rotary head H _S1 by 310 μm in the rotational direction. In this way, the head gap spacing between the rotary heads H _L1 and H _S2 and the head gap spacing between the rotary heads H _L2 and H _S1 are each set to extremely short values of 310 μm, so the double gap as shown in FIG. 6 is normally used. It is said to have a Yaphead configuration. That is, the head winding 25 is wound around the core 24, and the long-time mode rotary head H _L1 (or H _L2 ) having the gap _G1 has the head winding 25 wound around the core 26.
7 is wound, and one of the cores is mostly cut off and butted together with a standard mode rotating head H _S2 (or H _S1 ) having a gap G ₂ , and the gap interval L between both heads is is selected to be within the recording length of several H, but here, as an example, it is selected to be 310 μm, which is the recording length of 1H. Track width is 46μ for standard mode recording and playback.
Rotary heads H _S1 and H _S2 with a track width of 32 μm are used for long-time mode recording and playback.
Rotating heads H _L1 and H _L2 are used. Furthermore, when playing back still images by stopping the running of the magnetic tape, rotary heads H _L2 and H _S2 (or H _L1 and H _S1 ) having the same azimuth angle gap are used, and the previously recorded images on one track are By alternately reproducing the signals, a field still image without jitter can be obtained. In addition, during high-speed playback, in which the tape is run at a faster speed than during recording, as will be described later, the higher level of the two rotating heads with different azimuth angles that are in contact with the magnetic tape at that time is The head outputting the reproduced frequency modulated wave signal is selected. This embodiment uses such heads H _S1 , H _S2 , H _L1 and
This circuit is applied to an azimuth type helical scan magnetic recording/reproducing device or magnetic reproducing device having H _L2 . Next, an embodiment of the circuit of the present invention will be described. FIG. 7 is a block system diagram showing an embodiment of the circuit of the present invention together with the main parts of the reproducing device. In the figure, the same components as in FIGS. 4 to 6 are designated by the same reference numerals, and their explanations will be omitted. One embodiment of the circuit of the present invention shows a circuit section extending from the amplifiers 36 and 37 to the delay control signal generation circuit 59 in FIG. rotating head
H _L1 , H _L2 , H _S1 and H _S2 are PAL color video signal recording magnetic tapes 2 with track patterns not recorded in H arrangement as shown in FIG. 2A.
Play 3. A PAL color video signal is separated into a luminance signal and a carrier color signal, and then the luminance signal is frequency modulated to become an FM luminance signal. The carrier color signal is frequency-converted to an unoccupied frequency band below the band of the FM luminance signal, and at the same time, its color subcarrier is
As disclosed in No. 32273, the signal is converted into a low-frequency conversion carrier color signal in which phase shift processing and phase shift stop are alternately repeated every one track scanning period (here, every one field period). The above phase shift process is a process of shifting the phase of the color subcarrier by 90 degrees in a fixed direction every 1H. Now, if we assume that the magnetic tape 23 is to be played back at a faster running speed than during recording, the rotating heads H _S1 , which mutually constitute a double gap head,
and H _L2 (or H _S2 and H _L1 ) are, for example, T _S ,
Draw a scanning locus with a width indicated by T _L , and record the recording track t ₁ ~
_t12 , the recorded signal of the track recorded by the head having the same azimuth angle gap is reproduced. This allows for example rotating head H _S1
The FM luminance signals in the reproduced signals reproduced from the shaded parts of tracks t ₄ , t ₆ and t ₈ are as follows:
The level fluctuates as shown in Figure 9A, and the rotating head
The FM luminance signals in the reproduced signals reproduced from the matte areas of tracks t ₅ , t ₇ and t ₉ by H _L2 vary in level as shown in FIG. 9B. The output reproduction signals of the rotary heads H _L2 and H _L1 are supplied to terminals 32a and 32b of a switch circuit 32 via a rotary transformer (not shown) and preamplifiers 28 and 29 shown in FIG. Further, each output reproduction signal of the rotary heads H _S1 and H _S2 is supplied to terminals 33a and 33b of a switch circuit 33 via a rotary transformer (not shown) and preamplifiers 30 and 31. Switch circuits 32 and 33 connect rotary heads H _S1 , H _S2 , H _L1 and
The rotational phase detection pulse of H _L2 switches and connects the terminals 32a and 32b, 33a and 33b every track scanning period (here, every field period), and the switch circuit 32 connects the terminal 32a
When the switch circuit 33 is connected to the terminal 33a, switching control is performed so that the switch circuit 33 is connected to the terminal 33a. Therefore, from each common terminal of the switch circuits 32 and 33, a reproduction signal of the double gap head scanning the magnetic tape 23, that is, a rotary head H _L2 is output.
When H S1 and H _S1 are slidingly scanning on the magnetic tape 23, their reproduction signals are also transmitted to the rotating head.
When H _L1 and H _S2 are slidingly scanning on the magnetic tape 23, their reproduction signals are respectively taken out. The reproduction signal of the long-time mode rotary head H _L2 or H _L1 taken out from the switch circuit 32 is supplied to the terminal 35a of the switch circuit 35, and is also supplied to the envelope detector 43 through the amplifier 36. On the other hand, the reproduction signal of the standard mode rotary head H _S1 or H _S2 taken out from the switch circuit 33 is supplied to the terminal 35b of the switch circuit 35, and is also supplied to the envelope detector 44 through the amplifier 37.
is supplied to The switch circuit 35 is extracted from a waveform generation logic circuit 56, which will be described later.
Switching is controlled by a head selection signal as shown in FIG. 3, and the reproduction signal having a higher level among the reproduction signals inputted to the terminals 35a and 35b is selected and output. That is, the switch circuit 35 is connected to the terminal 35a during the high level period of the head selection signal shown in _FIG.
The reproduction signal reproduced by H _L1 is selectively output, and during the period when the head selection signal is at low level, it is switched and connected to the terminal 35b to select the rotary head H S1 or H _S1 for standard mode.
Selectively outputs the reproduction signal reproduced by H _S2 .
As a result, the FM luminance signal in the reproduced signal taken out from the switch circuit 35 is always taken out at a high level, as shown in FIG. 9D. As a result, conventionally, scanning the reverse track during variable speed playback resulted in a large drop in the level of the reproduced FM luminance signal, which caused noise bars on the playback screen, but this level drop is shown in Figure 9D. As shown, since this does not occur in this embodiment, a variable speed reproduction image without noise bars can be obtained. The reproduction signal taken out from the switch circuit 35 is
The FM luminance signal is demodulated by being supplied to the FM demodulation circuit 38, while the low-frequency conversion carrier color signal is supplied to the color signal processing circuit 39 and returned to its original band. It undergoes phase shift processing and is converted into a reproduced carrier color signal in which the phase shift is canceled. This reproduced carrier color signal is supplied to a terminal 42b of a 1H delay circuit 41 and a switch circuit 42 after crosstalk components from adjacent tracks are removed by a comb filter in the color signal processing circuit 39. The output signal of the 1H delay circuit 41 is configured to be supplied to the terminal 42a of the switch circuit 42, and the 1H delay circuit 41 and the switch circuit 4
2 constitutes a first variable delay circuit. Also,
The luminance signal processing circuit 40 performs predetermined signal processing such as dropout compensation and de-emphasis on the reproduced luminance signal taken out from the FM demodulation circuit 38. By the way, the magnetic tape 23 has H as mentioned above.
Since a track pattern is formed that is not aligned and recorded, as mentioned above, the period of the reproduced horizontal synchronizing signal is reproduced at the regular fixed period, and the color order of the reproduced carrier color signal is also according to the regular period determined by the PAL system. It is necessary to perform predetermined delay processing on the reproduced color video signal and the reproduced carrier color signal so that they are reproduced in sequence. Envelope detectors 43 and 44 shown in FIG.
A circuit section leading to a delay control signal generation circuit 59, which will be described later, is a circuit section for generating a delay control signal for the above-mentioned delay processing.The operation and configuration of this circuit section will be explained next. Envelope detectors 43 and 44 detect, for example, a positive envelope of the reproduced FM luminance signal in the input reproduced signal, and transmit a signal at a level corresponding to the envelope to a capacitor 45 constituting a high-pass filter.
and 46 to the comparator 47.
Here, the capacitors 45 and 46 convert the fluctuation component of the reproduced signal level corresponding to reverse track scanning of the head into a signal that is emphasized more than the level fluctuation component caused by variations in head reproduction sensitivity, etc., which occur at lower frequencies. It is provided for removal. That is, if the capacitors 45 and 46 were not provided, the envelope detectors 43 and 4
It is assumed that the reproduced FM luminance signal subjected to envelope detection at 4 is a signal as shown in FIGS. 10A and 10B, and that the head rotation phase detection pulse entering the input terminal 34 is a signal as shown in FIG. 10C. Then, the envelope detector 4 is connected to the comparator 47.
3 and 44, detection signals as shown by the broken line LP ₁ and the solid line SP ₁ in FIG. 10D are input and their levels are compared. Assume that the comparator 47 is configured to output a high level signal when the detected signal LP ₁ is higher in level than the detected signal SP ₁ .
The output signal of the comparator 47 is as shown in FIG. 10E. However, the output signal of this comparator 47 is
As shown at 63 in FIG. 10E, there is a waveform portion in which the pulse width is extremely narrow, and if this continues, stable head selection cannot be performed. Therefore, if a high-pass filter consisting of capacitors 45 and 46 is provided for the above purpose, the detected signal supplied to the comparator 47 through the capacitors 45 and 46 is shown by the broken line in FIG. 11A.
As shown by LP ₂ and the solid line SP ₂ , the signal becomes a signal in which the high frequency components are emphasized. As a result, the output signal of the comparator 47 becomes as shown in FIG. 11B, and the waveform portion with a narrow pulse width shown at 63 in FIG. 10E becomes wide as shown at 64 in FIG. This makes possible head selection operations. Here, if the tape running is stable and the sliding condition between the tape and the head is always good, the output signal of the comparator 47 shown in FIG. 11B is directly supplied to the switch circuit 35 as a head selection signal. , or may be used as an original signal on which to generate a control signal to obtain a necessary amount of delay. However, in reality, the sliding condition between the tape and the head is not always good, and erroneous detection of the playback signal level may occur due to instability of the so-called head contact, especially at the entrance and exit of the rotating drum. becomes a problem. Therefore, in this embodiment, a configuration is adopted to eliminate this erroneous detection of the reproduced signal level, and this configuration and operation will be explained with reference to FIGS. 12A to 12F. Assuming that the waveform of the head rotation phase detection pulse entering the input terminal 34 is shown in FIG. 12A (this waveform is the same signal waveform as in FIG. 10C), the output signal waveform of the comparator 47 is as shown in FIG. 12B. As shown in b, as mentioned above, due to the instability of the head contact particularly at the inlet and outlet portions of the rotating drum, the rising and falling edges of the head rotation phase detection pulse as shown at 65, 66 and 67 are Erroneous detection of the playback signal level occurs in the vicinity. The output pulse b of the comparator 47 including the erroneously detected pulse portions 65 to 67 is delayed by the integrating circuit 48, and the erroneously detected pulse portions 65 and 67 having extremely short widths are corrected, resulting in a signal c as shown in FIG. 12C. After being converted into the Schmitt trigger circuit 4
9, where it is waveform-shaped to form the waveform shown in FIG. 12D.
It is converted into a rectangular wave d as shown in . This square wave d
As shown in FIG. 12D, there is an erroneously detected pulse portion 68 due to an erroneously detected pulse portion 66 with a relatively long width.
It is included. The output rectangular wave d of the Schmitt trigger circuit 49 is
The signal is supplied to a phase comparator 51 within a phase locked loop (PLL) 50. As is well known, the PLL 50 variably controls the output oscillation frequency of a voltage controlled oscillator (VCO) 52 using the output phase error voltage of the phase comparator 51, and compares the phases of the oscillation frequency and the rectangular wave d with the phase comparator 51. It is said to be composed of
The VCO 52 is set to a center frequency according to the playback speed by the output voltage of a center frequency setting voltage generation circuit 53 (described later), and the phase of the output signal of the VCO 52 and the rectangular wave d including the false detection pulse portion 68 is The output oscillation frequency of the VCO 52 is controlled by a phase error voltage according to the phase difference between the two signals so that each signal is kept constant. The time constant of this loop is set to a sufficiently low frequency, so VCO5
The second output oscillation frequency is prohibited from fast fluctuations, and the first
It no longer follows the erroneously detected pulse portion as shown at 68 in FIG. 2D. PLL5 of false detection pulse part 68
0, the output oscillation frequency of the VCO 52 changes slightly, and its phase also changes slightly.
This is not a big problem because the signal that detects the crossing of the track of rotating heads H _L2 , H _S1, etc. is superior in terms of numbers and determines the majority. Therefore,
A signal e as shown in FIG. 12E is taken out from the VCO 52. Here, to explain the setting of the center frequency of the VCO 52, the magnetic tape 2 on which a PAL color video signal with a field frequency of 50 Hz is recorded.
At the time of N-times speed playback in which the tape running speed of No. 3 is N times the recording speed, the center frequency f _C is set as shown below in relation to the number of times the rotary head crosses the track at that time. f _C = 25 (N-1) [Hz] (However, N is positive when fast forwarding and negative when rewinding) In Figure 13, the playback speed is set in advance, for example, 2x, 5x,
Center frequency setting that selectively generates a voltage for setting the center frequency depending on whether the tape running direction of the playback speed is the same as the recording speed (fast forward) or the opposite direction (rewind). Voltage generation circuit 5
3 shows a circuit diagram of the first embodiment. In the figure, variable resistors 70, 71 and 72 generate voltages of values 3v, 6v and 10v, respectively, and supply the output voltages to terminals 73a, 73b and 73c of a switch circuit 73, respectively. Here the voltage of value v is equal to the center frequency setting voltage of 25Hz. The switch circuit 73 has an input terminal 74
According to the playback speed setting signal from
During double speed reproduction, the input voltage at the terminal 73c is selectively output to the non-inverting input terminal of the differential amplifier 78. On the other hand, the variable resistor 75 divides the voltage from the same DC voltage source as the variable resistors 70 to 72.
A voltage of 2V is taken out and supplied to terminal FF of the switch circuit 76. The switch circuit 76 is configured to selectively output the input voltage of either terminal FF or REW according to the playback direction setting signal from the input terminal 77. When the playback direction is fast forward, the input voltage of the terminal FF is input to the switch circuit 76. Selects and outputs voltage 2V, and when in the rewind direction, outputs 0V, which is the input voltage of terminal REW.
Select and output. The differential amplifier 78 generates a voltage equal to the difference between the output voltage of the switch circuit 73 applied to its non-inverting input terminal and the output voltage of the switch circuit 76 applied to its inverting input terminal, and outputs the voltage to the output terminal 79. Output as frequency setting voltage. Here, each value of the non-inverting and inverting input voltage and output voltage of the differential amplifier 78 and the resulting VCO
The relationship with the center frequency of 52 for each playback speed and playback direction is summarized as shown in the following table.

[Table] Thus, according to this embodiment, even at the same reproduction speed, the differential amplifier 78 performs processing that differs by 50 Hz depending on the reproduction direction, as can be seen from the above equation. Further, by generating the center frequency setting voltage by calculating two voltages determined by the reproduction speed setting signal and the reproduction direction setting signal, this embodiment is configured with a small number of voltage sources. Next, another embodiment of the center frequency setting voltage generating circuit 53 will be described with reference to the circuit diagram shown in FIG. In the same figure, a capstan rotation detection pulse with a repetition frequency corresponding to the rotation speed of the capstan is input to an input terminal 80, and a monostable multivibrator (mono multi) 82 in an F-V converter 81 is input to an input terminal 80.
is applied to That is, in this embodiment, as a tape running means during high-speed playback, the tape is not pressed by releasing the pressure bond between the capstan and the pinch roller and running the tape only by the rotational force of the rotating reel, but by using the pressure bond between the capstan and the pinch roller. It is applied to a device that runs a tape at high speed by increasing the rotational speed of the capstan faster than during recording without releasing the tape. The monomulti 82 and the integrating circuit 83 constitute an F-V converter 81, and the monomulti 82 has a 15th
When a capstan rotation detection pulse as shown in FIG. A comes in, a pulse with a constant pulse width as shown in FIG. As a result, a voltage proportional to the repetition frequency of the capstan rotation detection pulse as shown in FIG. On the other hand, the DC voltages of values v and -v taken out from the variable resistors 85 and 86 are applied to the terminals of the switch circuit 87.
Applied to FF and REW. This switch circuit 87
is determined by the playback direction setting signal from the input terminal 88.
It is configured to be switched and connected to the terminal FF side during fast forwarding and to the terminal REW side during rewinding, and its output voltage is supplied to the inverting input terminal of the differential amplifier 84. The output voltage of the switch circuit 87 varies depending on the playback direction even at the same playback speed as described above.
Used to shift by Hz. In this way, according to this embodiment, the center frequency setting voltage that always follows the tape running speed can be output to the output terminal 89, and the center frequency of the VCO 52 can be set in accordance with any playback speed. Can be done. Returning to Figure 7 again, to explain, VCO52
The output signal e is applied to a comparator 54, where the level is compared with a predetermined reference voltage from a variable resistor 55. The comparator 54 outputs a low level signal when the sawtooth wave signal e shown in FIG. 12E is higher than the reference voltage, and outputs a high level signal when the signal e is lower than the reference voltage. Therefore, a signal f as shown in FIG. 12F is taken out at its output terminal. During high-speed reproduction, this signal f passes through the waveform generation logic circuit 56 as it is and is supplied to the switch circuit 35 as the same head selection signal as the head selection signal shown in FIG. 9C. Here, during the high level period of the signal f, the reproduction signal of the long-time mode rotary head H _L1 or H _L2 is selectively output, and during the low level period, the reproduction signal of the standard mode rotary head H _S1 or H _S2 with a wide track width is output. A signal is selectively output. Therefore, the variable resistor 55
The reference voltage is selected to such a value that the low level period of the signal f is longer than the high level period. As a result, the period during which the reproduction signals of the standard mode rotary heads H _S1 and H _S2 can be obtained is
This is longer than the period during which reproduction signals from the long-time mode rotary heads H _L1 and H _L2 are obtained, and image quality deterioration at the head switching section can be prevented. The waveform generation logic circuit 56 is a circuit that outputs a head selection signal, and outputs the output signal f of the comparator 54, a mode signal indicating various operation modes from the input terminal 57, and a head rotation phase detection pulse from the input terminal 34. It generates a signal for head selection, which selects the rotary heads H _S1 and H _S2 in the standard mode, and forcibly selects the rotary heads H _L1 and H _L2 , respectively, in the long-term mode. Also, during high-speed reproduction, the signal f is output as is as a head selection signal. Further, the waveform generation logic circuit 56 outputs to the output terminal 58 a phase shift reference signal for canceling the phase shift of the reproduced low frequency conversion carrier color signal in the color signal processing circuit 39. That is, during high-speed playback, depending on the head selection, the reproduced low-frequency conversion carrier color signal from the track being reproduced has a signal that has undergone a phase shift and a signal that has not undergone a phase shift, which is shorter than the period of the head rotation phase detection pulse. Since the signals are reproduced alternately in cycles, the reference signal (in other words, the output from the head at which azimuth angle This is because it is necessary to output a signal indicating whether or not is selected. The head selection signal taken out from the waveform generation logic circuit 56 is supplied to the switch circuit 35 and the delay control signal generation circuit 59, respectively. The delay control signal generating circuit 59 is supplied with the head selection signal and the operation mode signal from the input terminal 57, and applies a switching pulse to the switch circuit 42 so that the switch circuit 42 always reproduces the reproduced conveyed colors in the correct color order. This circuit outputs a signal and outputs a delay control signal to the variable delay circuit 61 to variably control the delay time, and is basically a countdown circuit. FIG. 16 shows a specific circuit diagram of one embodiment of the delay control signal generation circuit 59. In the figure, input terminal 91
The head selection signal described above is input to the input terminal 92, the still playback mode signal is input to the input terminal 93, and the still reproduction mode signal is input to the input terminal 93.
is a mode signal that becomes high level during high-speed rewind playback, input terminal 94 receives a mode signal that becomes high level during high-speed fast forward playback, and input terminal 94 receives a mode signal that becomes high level during high-speed fast forward playback.
5 receives a mode signal which becomes high level in the long-time mode. That is, the input terminals 92 to
95 corresponds to the input terminal 57. First, the above-mentioned Fig. 2A recorded in long-time mode
To explain the operation when rewinding and reproducing a magnetic tape 23 having a track pattern as shown in _FIG. It becomes a waveform. That is, a head selection signal enters the input terminal 91 and is supplied to the inverter 96 through the diode _D1 , where the phase is inverted and the first signal is output.
After the waveform is set to the range shown by _T1 in Figure 7A, it is output to the output terminal 110 as a control signal, while
It is supplied to the input exclusive OR circuit 97. Further, the high-level high-speed rewind playback mode signal inputted to the input terminal 93 is applied to the inverter 99 via diodes D ₄ , D ₅ , resistor R ₁ , etc.
As shown in FIG. B, the low level is applied to each reset terminal of JK flip-flops 107 and 108. In addition, the above-mentioned high-speed rewind playback mode signal is transmitted through diode _D4 in the range shown in Figure 17C.
It is applied to the inverter 98 as a high level signal as shown in T ₁ , and after being converted to a low level here, it is applied to the exclusive OR circuit 97 . As a result, the exclusive OR circuit 97 outputs the range D in FIG. 17 that is in phase with the output signal of the inverter 96.
A pulse as shown in _T1 is taken and applied to each clock input terminal of JK flip-flops 107 and 109. J-K flip flop 1
07 has a high level voltage applied to its J input terminal and K input terminal, respectively, so it is inverted every time the pulse applied from its Q output terminal to the clock input terminal rises. A pulse as shown in the range T ₁ of E is taken out, and this output pulse is output as a control signal to the output terminal 111, while the two inputs are exclusively connected together with the high-level high-speed rewind playback signal shown in FIG. 17C. It is supplied to the OR circuit 108. Therefore, the exclusive OR circuit 108 outputs the 17th pulse which has a negative phase relationship with the Q output pulse of the flip-flop 107 shown in FIG. 17E.
A pulse as shown in the range T ₁ in Figure F is taken out,
The J input terminal of the J-K flip-flop 109 and the K
and the input terminals, respectively. Therefore, from the output terminal of the flip-flop 109, pulses as shown in the range _T1 in FIG. 17G are taken out. On the other hand, a high-level long-time mode signal is input to the input terminal 95, and the inverters 100 and 101
Since _{the signal is applied to the cathode of diode D 7 through}
Forward bias _D8 . Therefore, the high level signal taken out from the diode D ₅ and shown in the range T ₁ in FIG. 17C is applied to the inverter 99 via the resistor R ₁ as described above, but _the
The connection point between the anode of the diode _D8 and the anode of the diode _D8 becomes low level when the diode D8 is turned on. Therefore,
The output of inverter 102 is high level, the output of inverter 103 is low level, and the diode
D ₁₁ is turned off and diode D ₁₂ is turned on. By turning on diode D ₁₂ , input terminal 9
1 through the inverter 104 and the resistor _R3 , the pulse train as shown in the range _T1 of FIG. 17A is blocked from being transmitted. Therefore, the diode
A resistor is connected to the connection point between the cathodes of D ₉ and D ₁₀ , which is taken out from the output terminal of the flip-flop 109.
A pulse as shown in range T ₁ of FIG. 17G is taken out through R ₄ and diode D ₉ . This pulse is output as a control signal to output terminal 112 through inverters 105 and 106, respectively. The output control signals of output terminals 110 and 111 are respectively supplied to second variable delay circuit 61 shown in FIG. Here, the variable delay circuit 61 is controlled to a delay time as shown in the following table by a combination of high level (logic "1") and low level (logic "0") of the control signals from terminals 110 and 111. be done.

[Table] Therefore, the delay time of the variable delay circuit 61 that delays the reproduced color video signal from the mixing circuit 60 that mixes the reproduced luminance signal and the reproduced carrier color signal and outputs the delayed signal to the output terminal 62 is the same as that of the high-speed rewind. At the time of reproduction, it becomes as shown in the range _T1 of FIG. 17H (however, the unit of the numerical values shown in FIG. 17H and I is the horizontal scanning period). On the other hand, the output control signal of the output terminal 112 is applied as a switching signal to the switch circuit 42 shown in FIG. 7, and when it is at a low level, it is connected to the terminal 42a, and when it is at a high level, it is connected to the terminal 42b. As a result, the reproduced carrier color signal output from the color signal processing circuit 39 is given a delay time indicated by a numerical value within the range indicated by _T1 in FIG. The signals are outputted to the mixing circuit 60 in order. FIG. 18A shows the track pattern during high-speed rewind playback and the scanning locus of the center of the selected rotary head, respectively. The track pattern itself shown in FIG. 18A and FIG. 19A, which will be described later, is the same as the track pattern shown in FIG. 2A. Now, it is assumed that the track on which the first half field of the fifth frame F5 is recorded is recorded by a rotary head having the same azimuth angle gap as the rotary heads H _L2 and H _S2 , and Assuming that H _L2 and H _S1 are respectively scanning the magnetic tape 23 at the same time, the scanning locus of the center of the selected rotary head among rotary heads H _L2 and H _S1 is the 18th one.
The result is as shown by the solid line in Figure A. In other words, the rotating head H _L2 has the scanning line number "9" of the fifth frame F5.
At 120L, when the playback of the recorded signal for the period ended,
The rotation head H _S1 is switched so that the reproduction signal of the rotary head H S1 is obtained, and the rotary head H _S1 moves behind H _L2 in the rotational direction by the recording length of 1H, as shown in Figs. 4 to 6. Figure 18A
At 120S, the playback signal from the rotary head H _S1 is switched and output, and at the border of the next track, at the point shown at 121S, the playback signal from the preceding rotary head H _L2 is output by a recording length of 1H. The rotary head H L2 is switched to selective output, so the rotating head H _L2 is
Reproduction of the signal of the second half period of the scanning line number "11" of the fourth frame F4 at the position 121L preceding by 1H is started. Thereafter, in the same way, the rotating head H _L2 is
When it scans to the point indicated by 122L, it switches to the rotary head H _S1 , and the rotary head H _S1 reproduces the recorded signal at the positions 122S to 123S, and then the rotary head
Switched to H _L2 and rotating head H _L2 from 123L
The recorded signal at the position up to 124L is reproduced, and then the rotary head H _S1 is switched and the head H _S1 reproduces from 124S. As a result, the output reproduction signal of the switch circuit 35 shown in FIG. 7 becomes as schematically shown in FIG. 18B. The numerical values in FIGS. 18B and C and FIGS. 19B and C described later indicate the horizontal scanning line numbers of the reproduced luminance signal, and the diagonal lines indicate that the phase of the carrier wave of the color difference signal RY is inverted, Furthermore, the vertical lines separating the numerical values indicate the playback position of the horizontal synchronizing signal. Therefore, as shown in FIG. 18B, the output reproduction signal of the switch circuit ₃₅ is always 0.25H ( ₌ 1 /4H) H
A skew occurs. Therefore, in this embodiment, each time the rotating heads H _L2 and H _S1 are switched from one to the other, the variable delay circuit 61 controls the reproduced color video signal as shown in FIG. 17H. 0 → 3/4 → 2/4 → 1/4
→0→3/4→2/4→1/4→0→…(Time unit is H)
The delay time is switched in this order, and the delay time is set to 0 as shown in FIG.
→ 1 → 1 → 1 → 1 → 0 → 0 → 0 → 0 → 1 →... (time unit is H) By switching and adding delay time in the order, the color order is determined by the color difference as determined by the PAL system. Since a signal in which the carrier wave of the signal R-Y is alternately phase-inverted every 1H is output, the reproduced horizontal synchronization signal is always reproduced in a 1H period.
At the output terminal 62, reproduced color video signals in the order schematically shown in FIG. 18C are taken out. That is, up to position 120L shown in FIG. 18A, the reproduced signal shown in FIG. 18B is output as is, and during the reproduction period from positions 120S to 121S shown in FIG. 4H), the switch circuit 42 is connected to the terminal 42a and a delay time of 1H is given to the reproduced carrier color signal, so that the scanning line numbers "320" to "320" of frame F4 shown in FIG.
The reproduced signal of "323" becomes as shown in Figure C, and the reproduction period from the positions 121L to 122L shown in Figure A shows the scanning line number "11" of frame F4 as shown in Figure B.
The signals from to "14" are reproduced, but during this reproduction period, the delay time of the circuit 61 is 0.5H (=2/4H),
Since the switch circuit 42 is connected to the terminal 42a, it is placed immediately before the scanning line number "14" of frame F4.
A reproduced color video signal as shown in FIG. 18C in which 0.5H of noise occurs is extracted. Thereafter, in the same manner, position 122S shown in FIG. 18A
During the playback period from ~123S, the delay time of circuit 61 is
0.25H (=1/4H), the delay time of the reproduced carrier color signal is
1H, and during the reproduction period from the next position 123L to 124L, the delay time of the circuit 61 is OH, and the delay time of the reproduction carrier color signal is 1H. Therefore, the information content of the reproduced color video signal is as schematically shown in FIG. 18C. As shown in FIG. 18C, the reproduced color video signal is replaced with the previous video information during the 0 to 3/4H period immediately after the head is switched, and becomes a noise part, but this noise part is actually 10 at most
It can be almost ignored on the screen during high-speed playback at double speed (Figures 18A and 19A show the case of high-speed playback at 100x speed or higher for convenience of illustration, but in reality, such high-speed playback ), and from a broader perspective, the horizontal synchronization signal is reproduced uniformly with a 1H cycle, so no skew occurs. Furthermore, the order of the color signals is also correct. Therefore, high-quality high-speed rewinding and reproduction images can be obtained. Next, the operation when performing high-speed fast-forward playback of the magnetic tape 23 will be described. In this case, the 16th
Input terminal 9 of delay control signal generation circuit 59 shown in the figure
Since the head selection signal described above is input to 1,
The output signal waveform of the inverter 96 is shown in FIG. 17A.
The signal waveform will be in the range shown in T ₂ . Also, since the input terminals 94 and 95 among the input terminals 92 to 95 are at high level, the flip-flops 107 and 95 are at high level, respectively.
The input signal waveform of the reset terminal 109 is shown in FIG. 17B, and the input signal waveform of the inverter 98 is shown in FIG.
In addition, the output signal waveform of the exclusive OR circuit 97 is shown in D in the same figure, the Q output waveform of the flip-flop 107 is shown in _FIG. The signal waveform will be within the range shown. As a result, the control signal at the output terminal 112 has a waveform in the range shown by _T2 in FIG. 17G. Therefore, the delay time of the variable delay circuit 61 is the 17th delay time.
The delay time for the reproduced carrier color signal is switched as shown in the range T ₂ of FIG. 17 by the 1H delay circuit 41 and the switch circuit 42, as shown in the range T ₂ of FIG. . This allows the rotating head to be moved during high-speed fast forward playback.
When H _L2 (or H _L1 ) and H _S1 (or H _S2 ) are selected as heads and the scanning locus of the center of the selected rotary head is drawn as shown by the solid line in FIG. 19A, the above switch is activated. The reproduced signal of the circuit 35 is the 19th
As schematically shown in Figure B, a skew of 0.25H always occurs at the time of head switching, but as in the case of high-speed rewind playback, the period until the head switches is taken as 1 unit, and the skew is divided into 8 units. The 17th cycle
As a result of the delay time control shown in range _T2 in Figures H and I, there is no skew at the output terminal 62, and the color order is in the normal order, as shown schematically in Figure 19C. A reproduced color video signal as shown is extracted. Note that during normal playback in the long-time mode, the output signal of the inverter 96 shown in FIG.
As shown in range _T3 in Figure 7A, the level becomes low,
In addition, when the input terminal 95 is at a high level, the input terminal 92
.about.94 are at low level, the output signal of inverter 99 becomes high level as shown in range _T3 in FIG. 17B. The input signal of the inverter 98, the Q output signal of the flip-flop 107, and the output signal of the exclusive OR circuit 108 are shown in FIG.
As shown in range T ₃ of E and F, it becomes low level,
On the other hand, the exclusive OR circuit 97 and the output terminal 112
The control signal becomes high level as shown in range _T3 in FIG. 17D and G. As a result, the delay time of the variable delay circuit 61 and the delay time given to the reproduced carrier color signal supplied to the mixing circuit 60 are respectively the first
As shown in Figure 7 H and I, it is always zero and is never delayed. In other words, the head does not scan the reverse track during normal playback, so
The delay time control operation is stopped. In this way, the comparator 47 shown in FIG.
Since the circuit portion leading to the delay control signal generation circuit 59 is digital signal processing, it is relatively simple.
It is easy to integrate into an IC, and similar processing can be performed by sequential logical operations using microprocessor software, resulting in a simple configuration. Application Example Note that in the present invention, the gap interval between two rotary heads constituting a double gap head is not limited to 1H, but may be within several hours. Incidentally, when a magnetic tape with a track pattern with a deviation of 0.75H is played back at high speed in long mode and standard mode, as shown in Figure 2A, for the gap intervals of 1H and 2H, respectively, the required delay time is calculated. The amounts and order are summarized in the following table.

[Table] However, in the above table, Y+C is variable delay circuit 61
C indicates the delay time given to the reproduced carrier color signal by the 1H delay circuit 41 and switch circuit 42. Also, the time unit is H. As you can see from the table above, the gap interval is 2H.
In this case, the advantage is that no delay is necessary in the standard mode, but the way the delay time of the reproduced carrier color signal C is switched is significantly different between high-speed fast-forward playback and high-speed rewind playback in the long-time mode. There is a problem. In addition to the above-mentioned gap intervals, we investigated delay times for various gap intervals such as 5/4H, but we found that there was little difference in processing between high-speed fast-forward playback and high-speed rewind playback (periodicity of delay time switching). Taking into consideration the following points: the gap spacing is 1H, and the vertical deviation of the stitched images is large when the gap spacing is large. Furthermore, in the above embodiment, a case was explained in which a PAL color video signal is reproduced.
The present invention can be applied to color video signals that are switched every 1H, and can therefore be applied to SECAM color video signals, as well as black and white video signals. Also shown in Figure 7
A first variable delay circuit consisting of a 1H delay circuit 41 and a switch circuit 42 may be provided on the input side of the color signal processing circuit 39. Furthermore, although it is not necessarily necessary to have a double gearphead configuration, one of the two rotating heads configured to have a double gearphead configuration may be a head used for other purposes such as variable speed reproduction. Effects As described above, the present invention has the following features. The output signal of the first comparison means for comparing the levels of the reproduced frequency modulated wave signals of two rotary heads having gaps of different azimuth angles, which are provided close to each other, is passed through an integrating circuit to scan across the recorded track. Since a signal synchronized with the frequency component related to the number of times is generated and output, and this signal is used as the base signal for generating the delay control signal, the first problem mentioned above is caused by instability of the sliding condition between the tape and the head. Pulses that are considered to be noise that may be mixed into the output signal of the comparison means can be ignored, and as a result, the delay control signal can be stably generated, and
Accurate delay control is possible. Since the circuit for generating the signal on which the control signal is generated is constructed of a phase locked loop, noise can be removed with a relatively simple circuit construction. The center frequency of the variable frequency oscillator (usually a VCO) in the phase-locked loop is
Since it is set using the voltage generated based on the capstan rotation detection pulse, the required control signal can be generated for any playback speed, and the tape running speed can be changed. Stable operation can be achieved even in transient conditions. By selecting a reference voltage to be compared in level with the output signal of the phase-locked loop to a predetermined value, the output signal of this comparison means is selectively outputted as the reproduction signal of each of the two rotating heads adjacent to each other. Since it is also used as a switching signal for switching, it is possible to select the head with the wider track width of the two rotating heads for a longer period of time, thereby preventing deterioration in image quality at the head switching section.

[Brief explanation of drawings]

FIG. 1A is a diagram showing a part of a track pattern when a PAL color video signal is recorded in standard mode and an example of a head scanning locus during variable speed playback.
FIG. 1B is a diagram schematically showing an example of the arrangement order of the reproduction information contents of the reproduced color video signal when the track pattern of FIG. 1A is reproduced at variable speed.
Figure 2B shows part of a track pattern when a PAL color video signal is recorded in long-time mode and an example of a head scanning locus during variable speed playback. FIG. 3 is a block system diagram showing an example of a conventional device, and FIG. 4 is a diagram showing a recording/playback device to which the circuit of the present invention can be applied. FIG. 5 is a plan view showing an example of the head arrangement relationship, FIG. 5 is a diagram showing an example of the mounting height positional relationship of each head of a recording/reproducing apparatus to which the circuit of the present invention can be applied, and FIG. 6 is a plan view of the present invention. FIG. 7 is a perspective view showing the configuration of a double gap head that can be applied to a recording and reproducing apparatus to which the circuit can be applied; FIG. 7 is a block diagram showing an embodiment of the circuit of the present invention together with the main parts of the reproducing apparatus; FIG. 9A is a diagram showing an example of the head scanning trajectory during variable speed playback together with a track pattern.
~D are signal waveform diagrams for explaining the operation of the main parts of the block system shown in Figure 7, respectively; Figures 10A~E and Figures 11A and B are respectively with and without the high-pass filter in Figure 7. 12A to 12F are signal waveform diagrams for explaining the operation of other main parts of the block system shown in FIG. 7, and FIG. 13 and FIG. 14 is a circuit diagram and a circuit system diagram showing each embodiment of the center frequency setting voltage generation circuit 53 in the block system shown in FIG. FIG. 16 is a specific circuit diagram showing an embodiment of the delay control signal generation circuit 59 in the block system shown in FIG. 7. FIG. A diagram showing the signal waveforms and delay times to be given to the reproduced signal during high-speed rewind playback, high-speed fast forward playback, and normal playback of each part of the circuit. Figure 18A shows the center of the head selected during high-speed rewind playback. Figures 18B and 18C are diagrams showing an example of the scanning locus along with a track pattern, respectively, when the head scanning locus shown in Figure 18A was drawn without and with delay time control. FIG. 19A is a diagram schematically showing the arrangement order of reproduction information contents of a reproduced color video signal.
19 is a diagram showing an example of the scanning trajectory of the center of the head selected during high-speed fast-forward playback together with a track pattern, and FIGS. 19B and C are diagrams showing delay time control when the head scanning trajectory shown in FIG. FIG. 4 is a diagram schematically showing the arrangement order of the reproduction information contents of the reproduction color video signal when the reproduction color video signal is not performed and when it is performed. 7, 38... FM demodulation circuit, 8, 39... Color signal processing circuit, 9, 40... Luminance signal processing circuit, 1
0,41...1H delay circuit, 13...1/2H delay circuit, 15...1/2H skew detection circuit, 21...
Rotating body, 23...Magnetic tape, 32, 33, 3
5, 42... Switch circuit, 34... Head rotation detection pulse input terminal, 43, 44... Envelope detector, 45, 46... Capacitor constituting high-pass filter, 47, 54... Comparator, 4
8... Integration circuit, 49... Schmitt trigger circuit, 50... Phase locked loop (PLL), 53... Center frequency setting voltage generation circuit,
55... Variable resistor, 56... Waveform generation logic circuit, 57... Mode signal input terminal, 60... Mixing circuit, 61... Variable delay circuit, 62... Reproduction color video signal output terminal, 74... Reproduction Speed setting signal input terminal, 77, 88...Reproduction direction setting signal input terminal, 78, 84...Differential amplifier, 80...Capstan rotation detection pulse input terminal, 81...
F-V converter, 91...Head selection signal input terminal, 92...Still playback mode signal input terminal, 9
3...High-speed rewind playback mode signal input terminal, 94
...High-speed fast-forward playback mode signal input terminal, 95...
...Long time mode signal input terminal, 107, 109...
...J-K flip-flop, 110-112...
Control signal output terminals, H _L1 , H _L2 ...Rotary head for long time mode, H _S1 , H _S2 ...Rotary head for standard mode.

Claims (1)

[Scope of Claims] 1. The synchronization signal recording positions in the video signals of adjacent tracks in which the video signals are recorded after being at least frequency modulated by rotary heads having gaps of mutually different azimuth angles are mutually disposed in the longitudinal direction of the tracks. A magnetic tape having a track pattern recorded at a different angle is made to run at a speed different from that during recording, and a plurality of rotary heads having different azimuth angles and located close to each other are used as a set. The signal is supplied to a variable delay circuit that delays a reproduced video signal obtained by demodulating the reproduced frequency-modulated wave signal by appropriately selecting a set of rotating heads, and at least ensures that the horizontal synchronizing signal in the reproduced video signal is at a regular constant level. a control signal generation circuit for controlling a delay time so that the wave is reproduced in a periodic manner, and a first comparing means for comparing the level of the reproduced frequency modulated wave signal of each of the two rotating heads of the set; an integrating circuit that integrates the output signal of the first comparing means;
a first signal generating circuit to which the output signal of the integrating circuit is supplied and outputting a signal synchronized with a frequency component related to the number of traversal scans of the recorded track of the set of two rotary heads; A second step that compares the levels of the output signal of the generating circuit and the reference voltage, respectively.
1. A delay time control signal generation circuit during variable speed reproduction, characterized in that it comprises a comparison means, and a second signal generation circuit that generates and outputs the delay control signal based on the output signal of the second comparison means. 2. The first signal generating circuit includes a variable frequency oscillator whose center frequency is set to a frequency related to the number of traverse scans of the recorded track of the two rotary heads of the set, and the variable frequency oscillator and the integrating circuit. Claim 1 is a phase-locked loop comprising a phase comparator that compares the phases of both output signals and supplies a signal corresponding to the phase difference to the variable frequency oscillator. Delay time control signal generation circuit during variable speed playback. 3. The variable frequency oscillator uses a voltage generated based on a capstan rotation detection pulse with a repetition frequency that corresponds to the rotation speed of the capstan.
3. The delay time control signal generating circuit during variable speed reproduction according to claim 2, wherein the center frequency is set. 4. The output signal of the second comparison means is used as a switching signal for selectively outputting both reproduction signals of the two rotary heads of the set, and the reference voltage is used as a switching signal for selectively outputting both reproduction signals of the two rotary heads of the set. The delay time control signal during variable speed playback according to claim 1, wherein the delay time control signal is selected to a value that is selected for a longer period for the rotating head with a wider track width than for the other rotating head. generation circuit.