JPS62134848A - Reproducing device - Google Patents

Abstract

PURPOSE:To reduce the load on software greatly by controlling a recording medium feeding motor so that a judged phase is synchronized with the phase of a switching signal for plural rotary heads during high-speed reproduction. CONSTITUTION:A sample holding output SH is supplied as a phase error to a capstan motor 50 through a switch circuit 48 and an amplifier 55 during high-speed reproduction. Then, the motor 50 is placed under phase servocontrol so that a specific phase error voltage is obtained; and rotary heads HA and HB makes a scan on the recording track pattern in invariably fixed phase. A crossing position on a track which is different in rotary head azimuth angle is therefore the same position in a one-field period and noise bars are fixed on an image plane. Further, the noise bars are moved to an optional desired position on the image plane by operating a variable resistance 45R.

Description

[Detailed description of the invention]

The invention will be explained in the following order. A. Field of industrial application B. Summary of the invention C. Prior art D. Problems to be solved by the invention 1i'JI +,';j
E Means for solving the problem F Effect G Embodiment G1 Description of the first embodiment of the present invention (FIGS. 1 to 3) G2 Other examples of means for obtaining tape scanning phase information (υ) explanation(
4 to 6) Explanation of still another example of the G3 tape scanning phase information detection means (FIGS. 7 to 9) H Effect of the invention A Industrial field of application This invention uses a rotary head to This field relates to playback systems of devices that record and playback signals and audio signals, and particularly relates to high-speed playback techniques. B. Summary of the Invention The present invention is an apparatus for reproducing information signals from a recording medium in which a plurality of pilot signals having different frequencies are sequentially and cyclically frequency-multiplexed recorded on an information signal track, and during high-speed reproduction, a plurality of rotating heads are used. When scanning across the tracks, information indicating the scanning phase of the rotary head with respect to the recording track pattern is obtained by extracting the reproduced biloft signal, and the phase between this scanning phase information and the head switching signal is set to be a predetermined phase. This system controls the running of the recording medium, thereby fixing the position of the noise bar on the playback screen that occurs when the rotary head scans tracks with different azimuth angles. C. Conventional technology In home VTRs, when performing tracking control in which the rotary head correctly scans the recording track during playback, conventionally a fixed magnetic head is used to control signals formed in the longitudinal direction of the tape. This is done using playback control signals from the track. However, the method of using such a fixed magnetic head is disadvantageous because the width of the tape becomes wider and when it is desired to downsize the recording/reproducing apparatus, the fixed head cannot be installed due to the location. Therefore, a method of tracking control without using such a fixed head has been proposed. This method, for example,
As described in Japanese Patent Publication No. 3-116120 and Japanese Unexamined Patent Application Publication No. 59-65962, a pilot signal for low frequency tracking is recorded on a track on which a video signal is recorded, superimposed thereon by a rotating head, During playback, the amount of crosstalk of this pilot signal from adjacent tracks is detected to perform l-ranking servo. For this reason, the pilot signal is frequency-multiplexed so that it can be easily separated during playback, as a signal on the low-power side where there is no video signal recorded in the frequency spectrum i/ram, and it is also recorded at a frequency with a small azimuth loss. selected. First, an overview of this tracking control method will be explained. In this example, pilot signals of four different frequencies are cyclically and sequentially frequency-multiplexed recorded on diagonal tracks. For example, two rotating heads H with different azimuth angles
When recording is performed using a rotary head device in which A and HB are arranged 18° apart, the rotation of these two heads will cause recording tracks to be sequentially formed in a so-called overwriting state as shown in FIG. The head records video signals and records four different frequencies f1. f2. f3. f4
As shown in FIG. 10, the four pilot signals are sequentially changed for each track and recorded cyclically. That is, one rotary head HA rotates every other track T1. as shown in FIG. T3 is formed and F
At the same time, the M-modulated video signal is recorded on the track T1, and the pylon 1- signal with the frequency f1 is recorded on the track T1.
3, a pilot signal of frequency f3 is superimposed and recorded. In addition, every other track T 2 and T 4 are sequentially formed by the other rotary head HB to record an FM-modulated video signal, and the track T 2 has a frequency f.
The pilot signal of frequency f4 is superimposed and recorded on track T4. By repeatedly recording these tracks T1 to T4, pilot signals of four types of frequencies are also sequentially and cyclically recorded to these tracks T1 to T.fwdarw. In this case, during playback, tracks Ti and T are sent to head II.
When T3 is correctly scanned, it is a just tracking state, and when T4 is correctly scanned, it is a just trunking state. Therefore, assuming that the gap width of heads HA and HB matches the track width,
Head HA. When rlB sequentially scans tracks T1 to T4, in synchronization with this, signals P1 to P4 of frequencies f1 to f4 are supplied as reference pilot signals to a multiplication circuit, and the frequency difference with the reproduced pilot signal is detected. No frequency difference can be obtained in the just tracking state. On the other hand, if the tracking position deviates as shown in (1) and (2) of the head position (this is the case of head HA) in Fig. 10, then the adjacent track will detect a pilot signal with a frequency different from that of the reference pilot signal. Since the signal is obtained as crosstalk, a frequency difference occurs between the signal and the crosstalk signal, and the level is proportional to the amount of difference. Therefore, a frequency f
By selecting 1 to f4, tracking servo can be easily performed. That is, ΔfA=lft f21=lf3 f+ lΔ
Let fs=lf2-ra 1=lf4 Ex l. In this way, the existence of the frequency difference ΔfA means a shift to the right with respect to the head HA and a shift to the left with respect to the head HB, and the existence of the frequency difference ΔfH means a shift to the left with respect to the head HA, and a shift to the left with respect to the head HB. means a shift to the right,
The levels of the differences ΔrA and ΔfH are proportional to the amount of deviation. Therefore, in principle, these frequency differences ΔfA+Δru indicate the amount of tracking error, and just tracking can be achieved by controlling this so that it becomes zero. However, in the example shown in Figure 10, it is a case of so-called checkmarking, so as shown by the solid line (3) in the figure, the track to be scanned is scanned across tracks on both sides of the track by slightly the same amount. is the state of just tracking. Of course, just tracking occurs when the levels of the frequency difference fA and ΔfH are equal, and tracking control is performed by controlling so that the level difference between the difference Δr^ and 8'B becomes zero. FIG. 11 is a block diagram of an example of the tracking control device. This example is for 8 mm video, and the pilot signal is a signal that is even lower than the band of the low-frequency conversion carrier color signal. In the figure, the playback outputs of heads IIA and I(H) are rotary transformers (IIA) and (II
B), the head switching signal RFSI4 is supplied to the switch circuit (13) via the head amplifier (12^) and (12B), respectively, and is passed through the terminal (14) (Fig. 12A)
This switch circuit (13) switches between heads HA and HB.
In synchronization with the rotation of the tape, the heads HA or HB are alternately switched to one terminal and the other terminal for a period corresponding to a 180° angular interval in which the heads HA or HB scan the tape. Therefore, the output of the amplifier (15) is a signal in which the reproduction outputs of the heads HA and HB are continuously connected, and this signal is supplied to the reproduction signal processing system through the terminal (16). The output of the amplifier (15) is also passed through a bandpass filter (
21) and the pilot signal is extracted from the reproduced signal. The reproduced pilot signal from this bandpass filter (21) is supplied to a multiplication circuit (22). On the other hand, a pilot signal generation circuit (23) is provided, from which frequencies ft, f2 . ra, f4 reference pilot signal P1. P2. P3. P4 are obtained and these are supplied to switch turn 1/3 (24). This switch circuit (24) includes a switch control circuit (20
) are supplied with select signals SL1 and SL2 from St, 1 . By SL2, one of the four frequency pilot signals is connected to this switch circuit (
24). Switch control circuit (
20) receives the head switching signal RI from the terminal (14).
'S- is supplied, the select signals SL1 and SL2 change at the rising and falling points of this signal RFS-, and the reference pilot signal obtained from the switch circuit (24) is changed. For example, during the 180° period when the head HA scans the track T1, the switch control circuit (24) outputs the signal P1 with the frequency f1 as a reference pilot signal, and during the 180° period when the head HB scans the track T2, the signal P1 with the frequency f1 is sent as the reference pilot signal. Signal P2 of f2 is...
The four frequency signals P1 to P4 are sequentially switched and obtained as shown in Fig. 12B.
). The reference pyros signal from this switch circuit (24) is supplied to a multiplier circuit (22). Therefore, from this multiplication circuit (22), signals with frequencies Δf8 and ΔfB, which are the difference between the reference pilot signal and the reproduced pilot signal, are obtained, and these are respectively passed through the bandpass filter (25).
and (26), and the detection circuit (
27) and (28) to output DC level output SA.
and SB. Here, the gains of the bandpass filters (25) and (26) are made equal to each other. Detection outputs SA and SB of detection circuits (27) and (28)
are levels proportional to the amount of the frequency difference ΔfA and 8fB components, that is, the magnitude of the pilot signal included as crosstalk in the reproduced pilot signal, and
This corresponds to the tracking amount of the right and left adjacent tracks. These detection outputs SA and SB are supplied to a subtraction circuit (29), from which a subtraction output SD of both is obtained. This subtraction output SD is a signal indicating which side is more shifted, left or right, but as mentioned above, the frequency difference ΔfA
and ΔfB, the direction of deviation is opposite when scanning the head HA and when scanning the head I-(H. Therefore, the output sD of the subtraction circuit (29) is directly sent to one side of the switch circuit (30). is supplied to the input terminal of the switch circuit (31), and the polarity is inverted via the polarity inversion circuit (31).
30) is supplied to the (II!) terminal of 1/3 (30) or Hera)' of this switching signal RP, when the head 11Δ is scanning.
H
Then, the amplifier (32) generates a tracking error voltage St- corresponding to the direction of deviation. Therefore, if this is supplied to the cat's stand 1--, the tracking control will be enhanced.For example, if the head IIA is shifted to the right as shown by +21 in Figure 10, the tracking control will be enhanced. The reason for performing a strike check in such a state is that the IIF raw pilot signal from the low-pass filter (21) also includes the pilot signal of the adjacent track on the right in Fig. 10, as shown in Fig. 12C (4). Then, ■) From the arithmetic circuit (22), l + 121i' (l I)
Ni-1-Yo&=Head HA and 11 r3 Nitsui”
There is no right shift, and the frequency differences ΔfA and ΔfB are obtained alternately in each scanning period. Therefore, the detection circuit (27
) output SA is as shown in figure E, and the detection circuit (28)
The output SB becomes as shown in F in the same figure, and the subtracted output SD becomes as shown in G in the same figure. And tracking error signal SE
is in a state indicating a right-shift error, as shown in H in the figure. By the way, when a VTR performs high-speed playback in the forward and reverse directions, when the rotating head crosses tracks with different azimuth angles, this appears as a noise bar on the playback screen. However, if this noise bar is fixed on both sides of the playback screen, it is possible to check the content of the playback screen. Therefore, VTRs are usually controlled so that the noise bar is fixed on the playback screen during high-speed playback. -1- In VTRs such as 8mm video that adopt the 1-racking control method using 4-frequency pilot signals as described above, technology for fixing the noise bar and controlling the position of the noise bar on the screen has been developed. The applicant previously proposed 1 (see Japanese Patent Application Laid-Open No. 57-202185). This technique uses a tracking control circuit as shown in Fig. 11 to select the switching period of the reference pylon I-to-no 1- signal and the reference pylon I' (Mr+ frequency) according to +2J switching of the pilot signal played from the tape. D. Problems to be Solved by the Invention By the way, determining and controlling the standard pilot signal switching period, etc. in this way has conventionally been carried out using a microcomputer, and the software burden has been reduced. In addition, in the case of the method devised above, the noise pan 1 is controlled by controlling the phase of the rotating head T (A. It is possible to change the position of the playback screen], but the software becomes more complicated and this is not currently possible. In this invention, information signals are recorded alternately as one diagonal track by two rotary heads, and the above-mentioned When reproducing from a recording medium in which a plurality of pilot signals having different frequencies are cyclically recorded by the rotary head in a state where the frequency can be separated from the information signal, one pilot signal of one frequency is assigned to each track to the above-mentioned track, Means is provided for determining the phase of the reproducing rotary head with respect to the recording track pattern by detecting the level or frequency of a reproducing pilot signal separated from the output of the reproducing rotary head, and during high-speed reproduction, the phase determined by the above means is provided. The motor for feeding the recording medium is controlled so as to synchronize the phase with the switching signal of the two rotary heads. If the phase is synchronized with the rotating head switching signal RFS-, each rotating head will scan the recording track pattern with exactly the same scanning phase in each tape scanning period, and the noise bar will be fixed. By changing the synchronization phase between the switching signal RPSW and the head scanning phase, the position of the noise bar fixed on the screen can be moved. As a means of detecting the scanning phase of the rotary head with respect to the recording track pattern during high-speed reproduction, the magnitude of the beat frequencies ΔfA and ΔfB between the reproduced pilot signal and the reference pilot signal is as well as the case where tracking error is obtained. This is an example of detecting That is, in the same figure, (21') to (29') are the first
The circuit blocks are exactly the same as those of the tracking error detection system from the band pass filter (21) to the subtractor 1i'3 (2) in FIG. Therefore, the switch circuit V8 (24') receives the switching inputs dν'SI, 1' and S from the switch control circuit (20').
1. , 2' causes the head switching signal 1? It is switched as shown in FIG. 2B in synchronization with FsW (FIG. 2A). In this example, since the inverter (31) and switch circuit (30) of the example of FIG. 11 are omitted, the switching order of the reference pilot signal is switched between frequencies 12 and f4. In this example, the output signal SD' from the subtraction circuit (29') is supplied to the Schmitt circuit 1/3 (41) and shaped into a rectangular wave SC, and this rectangular wave SC is sent to the programmable counter (42). supplied to Since the period of the rectangular wave SC differs depending on the tape speed, this programmable counter (42) uses the signal RFS
This is to configure a frequency divider to enable phase comparison with -, and the frequency division ratio can be changed depending on the tape speed. For example, at 5x speed, the division ratio is 1/1. At 7x speed, it is 1/1.
At 1.5.9x speed, it is 1/2. The output signal of the programmable counter (42) is supplied to a ramp wave generation circuit (43) to form a ramp wave RMP that rises with a constant slope, and this is supplied to a sampling and hold circuit (44). On the other hand, the head switching signal RFS- from the terminal (14) is supplied to the monostable multi-by-break (45), and the signal NF
For example, at a predetermined time delay from the falling edge of SH, a pulse SP is obtained from this monostable multivibrator (45), and this is sent to the sampling and hold circuit (
44) as a sampling pulse. Now, description will be given of, for example, the time of 5x speed reproduction in which the rotary head scans the recording track pattern as shown in FIG. (50) is a capstan motor, this capstan motor (50) is coaxially provided with a frequency generator (51), and this frequency generator (51) is connected to a remoter (5).
A signal SFG with a frequency corresponding to the rotation speed of 0) is obtained,
This is supplied to a frequency dividing circuit (53) through an amplifier (52). The frequency dividing ratio of this frequency dividing circuit (53) is changed according to the tape speed, and the frequency divided output is supplied to the speed servo circuit (54), from which a speed error voltage is obtained, and this speed error voltage is applied to the amplifier. (55) to the capstan motor (50), and the speed of this motor (50) is 1'7il lot road (5
3) is controlled so that the frequency of No. 4 is constant. The frequency division ratio 1/N of the frequency dividing circuit (53) is selected to be equal to the double speed ratio of the tape speed. For example, when N=1 Assuming that the normal playback speed is 5x speed, N = 5. Thus, the motor (50) is rotated at 5x speed, and the tape is therefore fed at 5x the normal playback speed.At this time, If the scanning trajectory of 11B on the tape to the rotating head II is as shown in Fig. 3, then the rotating head HA and
(2) The flf raw pyroso 1~ signals from B are sequentially obtained in a frequency sequence as shown in FIG. 2B. On the other hand, the frequency sequence of the reference pilot signal is obtained by being switched according to the signal RFSH, as shown in FIG. Therefore, the detection output S obtained as the difference between the detection levels SA' and SB' of the beat frequencies ΔfA and ΔfB
D' becomes as shown in the figure, and the output rectangular wave signal SC of the Schmitt circuit (41) becomes as shown in the figure E. Therefore, the output RMP of the ramp wave generation circuit (43) becomes as shown in FIG. On the other hand, the sampling pulse SP from the monostable multi-bibreak (45) is obtained after a predetermined time t shorter than one cycle of the signal RPSW has elapsed from the fall of the signal RFSW, as shown in FIG. Then, the ramp wave RMP is sampled by this sampling pulse SP, and the sampled value is held in the capacitor (44C). This sample-and-hold output SH (H in Figure 2) is supplied to the amplifier (
46) and is supplied to one input terminal A of the °ζ switch circuit (48). This switch circuit (48) has a terminal (
A switching signal SW is supplied through 47), and the switch circuit (48) is switched to one input terminal A during high-speed reproduction, and switched to the other input terminal B during normal reproduction. Therefore, during high-speed playback, the sample hold output S
H is connected to this switch circuit (48) by 1ffl, and the amplifier (
55) to the capstan motor (50) as a phase error. Then, a phase servo is applied to the capstan motor (50) so that the phase error voltage becomes a predetermined value. Recording track pattern 2 is scanned. Therefore, the position where the rotating head crosses tracks with different azimuth angles is the same position during one field period,
The noise bar will be fixed on the screen. A variable resistor (451?) that determines the time constant of the monostable multivibrator (45) for forming the sampling pulse SP.
) by changing the resistance value of head switching signal 1? Time t from the falling point of FsW to sampling pulse SP
By changing , the scanning phase of the rotary heads HA and HB on the tape changes, and therefore the position of the noise bar fixed on the screen also changes. In other words, you can move the noise bar to any desired position on the screen using this variable resistor (45
This can be easily done by manipulating R). Note that during normal playback, the switch circuit (48) is switched to the other input terminal B by the switching signal SW, but at this time, the tracking control circuit system configured as shown in FIG. An error voltage is obtained through this switch circuit (48). At this time, the speed of the capstan motor (50) is controlled so that the frequency division ratio of the speed servo system frequency dividing circuit (53) is 1/N, N=1, and the normal playback tape speed is achieved. , this speed error is added to the tracking error from this switch circuit (48) and is supplied to the capstan motor (50), and the rotary heads HA and HB move to the recording track Tl. T2, T3, and T41 are each scanned correctly. Incidentally, when comparing the signal RpSH and the tape scanning phase information SC, contrary to the example in FIG.
42) may be used to form a sampling pulse from the frequency-divided signal and sample the ramp wave. Further, the means for comparing the phases of both the signal Rpsn and the phase information SC is not limited to the above-mentioned method, but it goes without saying that various means can be used. In this example, during high-speed playback, the relative speed of the rotating head to the tape will deviate from the recording speed, unless correction is made by changing the rotation speed of the rotating head, and the playback frequency will also deviate by that amount. , the beat frequency ΔfA+ΔfB also shifts. Therefore, if the deviation in the relative speed of the rotating head is large, the band pass filter (25) and (2
6), and as a result, the S/N of the tracking error detection system based on this regenerated pilot signal increases.
becomes worse. Therefore, although not shown in this example, the rotating head HA
A drum speed servo is applied so that the relative speed of , HB with respect to the tape remains constant regardless of changes in tape speed. This is possible, for example, by applying a servo to keep the horizontal synchronization frequency in the reproduced video signal constant. Description of another example of means for obtaining G2 tape scanning phase information FIG. 4 shows another embodiment of the means for obtaining tape scanning phase information of the apparatus of the present invention which employs a level detection method. In this embodiment, the relative speed of the rotary head is not kept constant, and the above-mentioned drawbacks do not occur, and the S/N ratio is good (
This makes it possible to detect pilot signals. In other words, in this example, the frequency of the reproduced pilot signal is compared with the reference frequency to detect the reproduced pilot signal of that frequency. By making it possible to obtain a signal with a followed frequency, the pilot signal can be detected with a good S/N ratio even during variable speed reproduction. Furthermore, in this example, the frequency to be extracted by the bandpass filter of the regenerated pilot signal detection system and the passing center frequency are approximately equal, so that a bandpass filter with a narrow bandwidth can be used. (61) is an input terminal to which the reproduction signal obtained by the heads HA and HB alternately scanning the tape is supplied, and the signal passing through this input terminal (131) is sent to the RF amplifier (62).
is supplied to a bypass filter (63) through which the luminance signal is separated from the reproduced color video signal. This luminance signal is supplied IItm times to the FIPr (64) and FM
The signal is demodulated, and the demodulated output is supplied to a synchronization separation circuit (67) through a low-pass filter (65) and a de-emphasis circuit (66), from which a synchronization signal is obtained. This synchronization signal is supplied to a half-H killer circuit (68) and converted into a horizontal synchronization pulse from which the equalization pulse within the vertical blanking interval has been removed, and this is supplied to a PLL circuit (69). By the way, in the case of the above-mentioned 8 mm video, the pilot signal frequencies fx, f2 . f3. f4 is selected to be interleaved with the horizontal frequency f of the video signal so as not to affect the video signal, but generally each signal is obtained by dividing the master clock. For example, in the 8 mm video standard (NTSC), the master clock frequency fM is fH=378fH, and the frequencies f1 to f4, ΔfA, and Δre are selected as follows. f 1 = f M / 58 = 6.517 f H
#102.542kHzf2=fM/50
= 7.560f H# 11B, 949kHzf
3 = f M / 36 = 10.500f H#
165.207kHzf4=fM/40=
9.450f H#148.686kHzΔfA=f
2-fz = 1.043fH# 16.407k
HzΔfA=f3f4= 1.050fn ” 1
6.521kHzΔfs-f4r 1- 2.933r
s # 46.144ktlzΔf B= f 3-
fv = 2.9401'I (# 46.25F
The tkllzPLL circuit (69) is for obtaining this master clock M CI (from which the frequency r M = 3781 is phase-locked to this horizontal synchronization pulse).
++ master clock MCK is obtained. This master clock MCK has a phase "
Since the frequency is J, the frequency corresponds to the relative speed deviation of the rotating head. This master clock MCK is applied to the first to fourth frequency dividing circuits (
701) to (704). Then, the master clock MCK is input to the frequency dividing circuit (701
), the frequency is divided into 115B and from this the frequency f1
A signal of frequency r2 is obtained, and the frequency is divided by 1150 at the frequency division port I/3 (702) to obtain a signal of frequency r2, and a signal of frequency r2 is obtained from this signal at the frequency division port 1/8 (70-1).
36, from which a signal of frequency f3 is obtained,
In the frequency dividing circuit (704), the frequency is divided by 1/40 and a signal of frequency f4 is obtained from this. The signal with frequency f1 from the frequency divider circuit (701) and the signal with frequency f2 from the frequency divider circuit (702) are switched by the switch circuit (71A), and the frequency divider circuit (703) ) and a signal of frequency f1 from the frequency dividing circuit (704) are switched by a switch circuit (71B). And head cutting signal from terminal (72)!
i'FsW (5th doujin) is a switch circuit (71A)
and (71B), thereby e.g.
As shown in Figures C and D, during the period when the head HA scans the tape, a signal with a frequency f1 is taken out from the switch circuit (71A), and a signal with a frequency f3 is taken out from the switch circuit (71B). During the period when the head HB scans the tape, the switch circuit (71A
), a signal with frequency f2 is transmitted from the switch circuit (71
B) are switched so that signals of frequency f4 are respectively extracted. The frequency signals from these switch circuits (71A) and (71B) are (3) arithmetic circuits (73A) and (73B).
) and are each 11) multiplied with a signal of frequency fs, for example 110klly, from a fixed oscillator (74). The output signal 1 of this l) arithmetic circuit (73A) and (73t1) is a bandpass filter (75A) and (751S).
From these, the frequency conversion and frequency from the switch circuits (71^) and (71B) are supplied to

[Signals with a frequency equal to the sum of the S signals are obtained. And these pan;゛pass filter (75^) and (
The output signal of IJ) arithmetic circuit (76A) and (75B)
76B). On the other hand, the reproduced signal outputted from the amplifier (62) is supplied to the band-pass filter (77), and the reproduced pilot signal is output from the band-pass filter (77). (76A) (
76B). Now, for example, when the track 1'1'8 is playing back on the track Ti over the track Tz on the right, the band pass filter (77) will detect the 6th As shown in the doujinshi, the frequency f1±Δ and “
2 ± Δ pi "1 soto signal is obtained. On the other hand, if at this time a signal with frequency fs + fx ± Δ is obtained from the band pass filter (75A) as shown in Fig. 6B,
From the multiplication circuit (76A), as shown in Figure 6C,
(f2±Δ)+ (fs +ft±Δ)−f1+f2
+fs±2Δ ■(fs+fx±Δ)−(f2±Δ) =(g +f 1f 2 ■(, fs+f, ±Δ)+ (fx±Δ)=rs+2<
Four frequency components are obtained: (s±Δ) (fs+fi±Δ)−(Ex±Δ)=fs. The output of this fi calculating circuit (76A) is supplied to a narrow band pass filter (78A) having a passing center frequency fs, and only the component of the frequency fs (2) is extracted therefrom. This frequency fs component is obtained by multiplying the frequency f1 component of the reproduced pyro throat signal, and has a level corresponding to the level of the reproduced pyro throat signal of frequency f1. Similarly, when a signal with frequency fg +r2 ±Δ is obtained from the band-pass filter (75A), the signal at frequency 12: (contained in the reproduced pilot signal from the band-pass filter (77) At this level, a signal of frequency fl+ is obtained as the output of the multiplication circuit (76A'), and this is sent out through the bandpass filter (78A).In other words, the component of frequency rs obtained from this bandpass filter (78^) is nothing but the detected component of the reproduced pilot signal of frequency f1 or frequency 12. The output of this bandpass filter (78/l) is supplied to a level detection circuit (79A), and the level of the component of frequency fs is detected. From this, the detection output SAA is obtained. Also, the signal of frequency f3 from the multiplication circuit (7611) is passed from the bandpass filter (7511) to the frequency fs+f
When a signal of 3±Δ is obtained, it is obtained at a level corresponding to the level of the reproduced pilot signal of frequency f3, and the frequency of the pan 1' pass filter (75B) is equal to fs + f4.
When 16 months of ±Δ are obtained, the reproduction pi t of frequency f4
Depending on the level of the signal, the signal will have a level of 3]. And this multiplication circuit (76B
) is extracted through a narrowband bandpass filter (78B) with a passing center frequency fs, and is supplied to a detection circuit (79B) to obtain a frequency fs component.
The component of s is level detected, and the detected output SBB is obtained. Frequency fs obtained from bandpass filter (78B)
As is clear from the above, the component of
is the detected component of the reproduced viroft signal, and the level detection output SBB is nothing but the detected level. Here, the multiplication circuits (76A) and (76B) use the reproduced pilot signal and the bandpass filters (75A) and (76B).
75B), and the frequency fs component is obtained as a frequency difference, so the frequency deviation Δ is canceled out, and the detected frequency is always fs and does not include the frequency deviation. Then, the frequency f1. The detection output SAA of the regenerated pilot signal of f2 and the frequency f3. The detected output SBB of the reproduced pilot signal of f4 is supplied to a subtraction circuit (80), and the output 5r3B is subtracted from the output S8A, thereby obtaining the subtracted output SDD. The output S T ) D of this subtraction circuit (80) is supplied as is to one input terminal of the switch circuit (old), and its polarity is inverted by the polarity inversion circuit (82), and the output is supplied to the other input terminal of this switch circuit (81). is supplied to the input end of and,
The head switching signal RI'I from the terminal (72) is applied to this switch 1/3 (81) by a frequency divider (83).
The signal INV divided by /2 is supplied as a switch control signal, whereby this switch circuit (81) is alternately switched between one input terminal and the other input terminal every rotation of the rotary head. For example, FIG. 5 shows a timing chart during quadruple speed playback, and shows the head switching signal 1? Based on the PSW (A in the figure), the switch circuits (71A) and (71B) are switched in the same way as during normal playback, and the fx, I2 . Frequency signals of I3 and I4 are obtained, respectively. At this time, the regenerated pilot signal is
If the head HA,i (B) scans as shown in Fig. 5J, the result will be as shown in Fig. 5B. Therefore, the output SAA of the detection circuit (79^) will be as shown in Fig. 5E.
The output SBB of the detection circuit (79B) becomes as shown in F of the figure, and the output SDD of the subtraction circuit (80) becomes as shown in G of the same figure. Therefore, the switching signal IN as shown in FIG.
When the switch circuit (81) is switched by V, the signal SEE from this switch circuit (81) is a signal with a period corresponding to the tape speed at 4x speed, as shown in FIG. In contrast, a signal corresponding to the tape scanning phase can be obtained. Similarly, during variable speed playback, the rotary heads HA and HB scan across the number of tracks corresponding to the tape speed, so the output S of the switch circuit (81)
As EE, at all tape speeds,
A signal having a period corresponding to the tape speed and corresponding to the tape scanning phase is obtained with respect to the switching signal RFS-. The tape scanning phase information SE of the rotating head obtained in this way
E is shaped into a rectangular wave by the Schmitt circuit (84), and then compared in phase with the head switching signal RFS- in the same manner as in the previous example, and the phase of the capstan motor (50) is controlled by the comparison output. Noise bar is now fixed. G3 Tape scanning phase information + lJ detection - Explanation of further embodiments of stage The example of the tape speed information +111 detection means described above can detect the ++f raw pilot signal with good S/N even if the relative speed of the rotating head changes. In this case, if a drum servo is applied to keep the relative speed of the rotating head constant even when the tape speed changes, the reproduced pilot signal frequency δU can be converted into voltage and extracted to detect the pilot signal. Figure 7 shows an example of a drum speed servo loop where the relative speed of the rotating head is constant. The master fushi dock MCK is supplied to the frequency detection circuit (92) via the frequency dividing circuit (91), and a voltage according to the frequency is 111, which is supplied to the drum speed servo circuit (93), and the frequency detection circuit The servo is turned on so that the frequency detected in (92) is constant, that is, the relative speed of the rotating head is constant.When this drum speed servo is turned off, the reproduction pilot signal frequency does not change during variable speed playback, so the detection signal of the playback pilot signal with frequency rt/f3 and the frequency f2/f4 are determined as follows.
A two-phase detection signal is obtained with the detection signal of the regenerated pilot signal. That is, FIG. 8 shows an example of the detection system, in which a reproduced pilot signal extracted by a band-pass filter (101) is supplied to a trap circuit (103A) that attenuates components of frequencies f2 and f through an amplifier (102). From this, a regenerated pilot signal of frequency f1 or f3 is obtained, and this is supplied to a frequency-voltage conversion circuit (104A) to convert it into a voltage corresponding to the frequency. In this case, for example, the frequency f1
The conversion characteristics are determined so that a voltage of a low level with respect to the high level 1 frequency f3 can be obtained from the frequency voltage conversion circuit (104A). The output of this frequency-voltage conversion circuit (104^) is supplied to the Schmitt circuit (1068) via the rectifier circuit (105A) to generate a rectangular wave of 5CA.
(For example, see FIG. 9C). Similarly, a trap circuit (
103B), from which a regenerated viroft signal of frequency f2 or r4 is obtained, which is supplied to a frequency-voltage conversion circuit (104B) and converted into a voltage corresponding to the frequency. In this case, the conversion characteristics are determined so that, for example, a voltage at a high level for frequency f2 and a voltage at a low level for frequency f4 can be obtained from this frequency-voltage conversion circuit (104B). This frequency-voltage conversion circuit (104
The output of B) is supplied to a Schmitt circuit (106B) via a rectifier circuit (105B) and shaped into a rectangular wave SCB (see, for example, FIG. 9C). In this way, the output of the Schmitt circuit (1068) is a detection signal of the reproduced signal of frequency f1/fa, and the output of the Schmitt circuit (106B) is a detection signal of frequency f2/f4. A detected signal of the regenerated pilot signal is obtained. The detection signals of these Schmitt circuits (106A) and (106B) are supplied to one and the other input terminals of a switch circuit (107), and this switch circuit (107) is switched by a head switching signal RFSW (Fig. 9A). . The output 5 cc (for example, see FIG. 9) of this switch circuit (107) is supplied as it is to one input terminal of the switch circuit (10B) and is also supplied to the other input terminal via the inverter (109). Then, the head switching signal RFSW is frequency-divided by a frequency divider (110), and this switch circuit (108) is switched by the frequency-divided output INV (FIG. 9F).
08) At a period corresponding to the tape speed, an output signal SCD (for example, see FIG. 9C) which is tape scanning phase information is obtained in response to the head switching signal RFSH, and this is sent to the output terminal through the amplifier (111). (112). The signal SCD derived to this output terminal (112) is sent to the head switching signal 1.3 in the same manner as in the previous example. J] The noise bar is fixed at the same level as the playback screen by comparing the phase with the sweat SW and controlling the capstan motor so that the phase difference between the two is constant. By changing the phase difference between the two, which is kept constant, the position of the noise bar on the screen can be changed. H Effects of the Invention According to the present invention, there is no need to change the sequence switching order of the reference pilot signal according to the reproduced pilot signal as in the past, but it is only necessary to switch the sequence in synchronization with the head switching signal. can significantly reduce the burden on In addition, the fixed position of the noise bar can be easily changed by simply changing the phase difference between the head switching signal and the tape scanning phase information of the rotating head, making it easy to move the noise bar to a position where it does not interfere with the screen. It is something that can be done.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an example of the essential parts of the device of this invention;
3 and 3 are diagrams for explaining the operation thereof, FIG. 4 is a block diagram of another example of the main part of the device of the present invention, and FIGS. 5 and 6
The figures are diagrams for explaining the example in Figure 4, Figures 7 to 9 are diagrams for explaining still other examples of the device of the present invention,
FIG. 0 is a diagram showing an example of a recording track pattern, FIG. 11 is a block diagram showing an example of a tracking control device, and FIG.
FIG. 2 is a timing chart for explaining the example in FIG. 11. (21) (21') and (77) (101) are band pass filters for extracting pilot signals from the head reproduction output; HA and HB are rotating heads; (50)
is a capstan motor.

Claims (1)

[Claims] Information signals are sequentially recorded as diagonal tracks one by one by a plurality of rotating heads with different azimuth angles, and a plurality of pilot signals with different frequencies are recorded by the rotating heads on the tracks in a state where the frequency can be separated from the information signal. When reproducing from a recording medium in which a pilot signal of one frequency is assigned to each track and cyclically recorded, the above-mentioned method is achieved by detecting the level or frequency of the reproducing pilot signal separated from the output of the rotary reproducing head. Means is provided for determining the scanning phase of the reproducing rotary head with respect to the recording track pattern,
A reproducing apparatus that controls a motor for feeding the recording medium so that the phase determined by the means is synchronized with the switching signal of the plurality of rotary heads during high-speed reproduction.