JPS62128050A - Tape running controller - Google Patents

Abstract

PURPOSE:To attain reel servo of certain tape speed by using the fact that the repeat period of a pilot signal extracted from the reproduced signal obtained from a rotary head corresponds to the tape speed and applying reel servo which controls a reel base driving motor so that said period is a prescribed value. CONSTITUTION:A timing chart for 4-fold speed reproducing is shown in the figure, and an output SA of a detecting circuit 29A, an output SB of a detecting circuit 29B, and an output SD of a subtracting circuit 30 are as shown in figures E, F, and G respectively. Consequently, a switch circuit 32 is switched by an inversion signal INV shown in a figure H, and a signal having the period corresponding to the tape speed for 4-fold speed reproducing is obtained as a signal SE from the switch circuit 32 as shown in a figure I. Since rotary heads HA and HB scan across tracks, whose number corresponds to the tape speed, for variable speed reproducing, the signal of the period corresponding to the tape speed is obtained as the output SE of the switch circuit 32 in all kinds of tape speed similarly. Thus, this output signal SE is used to apply reel servo of certain tape speed.

Description

[Detailed description of the invention] The invention will be explained in the following order.

A. Field of industrial application B. Outline of the invention C. Prior art D. Problem to be solved by the invention E. Means for solving the problem F. Effect G. Embodiment G1 Description of an embodiment of this invention (Fig. 1) - Fig. 4) Explanation of an example of the G1-1 tap speed detection means (Figs. 1 - 3) Explanation of an example of the G1-2 reel servo circuit (Figs. 1 and 4)
Figure) Description of other examples of G2 reel servo circuit (Figures 5 and 6) Description of other examples of G3 tape speed information detection means
(Figures 7 to 9) H Effect of the Invention A Industrial Application Field This invention performs constant tape speed constant servo during playback of a device that records and plays back video signals and audio signals using a rotating head. The present invention relates to a tape running control device.

B. SUMMARY OF THE INVENTION This invention uses a rotating head to generate information on an information signal track.
When reproducing a tape in which a plurality of pilot signals having different frequencies are cyclically frequency-multiplexed by assigning one frequency pilot signal per 11-rank, tape speed information is obtained from the repetition period of the reproduced pilot signal from the tape, This makes it possible to control the reel stand motor and perform reel servo at a constant tape speed.

C Conventional technology For popular home VTRs, there is a re-rotation system.

Tracking control in which the tape correctly scans the recording track has conventionally been performed using a fixed magnetic head and a reproduction control signal from a control signal trunk formed in the longitudinal direction of the tape. but,
This method of using 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 Application Laid-Open No. 3-116120 and Japanese Patent Application Laid-Open No. 59-65962, a low-frequency tracking pilot signal is recorded on a track for recording a video signal by a rotating head, superimposed on this, and During playback, tracking servo is performed by detecting the amount of crosstalk of this pilot signal from adjacent tracks. For this reason, the pilot signal is frequency-multiplexed and recorded so that it can be easily separated during playback, as a low-frequency signal in the frequency spectrum where there is no recorded video signal, and the frequency is selected to have a small azimuth loss. Ru.

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 180° apart, the rotation of these two heads will cause the 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. fg, f*
The four pilot signals are sequentially changed for each trunk and recorded cyclically as shown in FIG.

That is, as shown in FIG. 10, one rotary head HA forms every other track T3, and the F
At the same time, the M-transformed video signal is recorded, and the pilot signal of frequency f1 is recorded in the truck T1, and the pilot signal with the frequency f1 is transferred to the trunk T3.
A pilot signal of frequency f3 is recorded in a superimposed manner on each of the lines.

Also, the other rotary head HB rotates every other track T2. T4 are sequentially formed and an FM modulated video @ signal is recorded, and a pilot signal of frequency f2 is superimposed on track T2, and a pilot signal of frequency r4 is recorded on track T4, respectively. .

By repeatedly recording these trunks T1 to T4, pilot signals of four different frequencies are also sequentially and cyclically recorded to these tracks T1 to T4.

In this case, during playback, the head HA is on tracks T1 and T3.
When the head HB correctly scans the tracks T2 and T4, it is in a just tracking state, and when the head HB correctly scans the tracks T2 and T4, it is in a just trunking state. Therefore, assuming that the gap width of the heads HA and HB matches the track width, when the heads HA and HB sequentially scan the trunks T1 to T4, the frequency f L is synchronized as a reference pilot signal. When the -f4 signals P1 to P4 are supplied to a multiplication circuit and the frequency difference with the reproduced pilot signal is detected, no frequency difference is 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 trunk will detect a biloft 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 the difference.

Therefore, the frequency f is set such that the frequency difference is the same between tracks T1 and T3 and between tracks T2 and T in the direction of deviation.
Tracking servo can be easily performed by selecting 1 to f. That is, AfA=lft f21=lf3 r4 lΔf
B=lf2 f31=lf4 fl 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 ΔfB 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, and the levels of the differences ΔfA and Δ′B are proportional to the amount of shift.

Therefore, in principle, these frequency differences ΔfA.

ΔfB indicates the amount of tracking error, and if this is controlled to become zero, just tracking can be achieved.

However, since the example in Fig. 10 is a case of so-called overwriting, as shown by the solid line (3) in the same figure, there is a situation in which the track to be scanned is scanned across tracks on both sides of the track by slightly the same amount. It is in a state of just tracking.

In other words, when the levels of the frequency differences ΔfA and Δ'B are equal, just tracking occurs, and the differences ΔfA and Δr
Tracking control is performed by controlling so that the level difference of B becomes zero.

By the way, when tape feeding is performed on a reel stand and control to keep the tape speed constant is required, the conventional 1/1
In a 2-inch home VTR, control is performed by keeping the cycle of control signals reproduced from longitudinal tracks of the tape constant using a fixed magnetic head for tracking control.

D. Problems to be Solved by the Invention However, when a tracking control method that does not use a fixed head is used, as in the case of 8mm video as mentioned above, when the tracking control is performed in the longitudinal direction of the tape as in the conventional case, There was no signal from the track, and there was no proper means to control the reel stand drive motor to perform reel servo at a constant tape speed.

E. Means for Solving the Problems This invention records an information signal as a diagonal track by a rotating head, and also records a plurality of pilot signals having different frequencies by the rotating head in a state where the frequency can be separated from the information signal. When playing back from a tape that is cyclically recorded with one frequency pilot signal assigned to each track, a frequency signal corresponding to the tape speed is generated from the playback pilot signal separated from the output of the playback rotary head. The frequency signal is used to control the reel drive motor to maintain a constant tape speed.

F Effect The repetition period of the pilot signal extracted from the playback signal from the rotating head is a period corresponding to the tape speed, so the reel drive motor is controlled or the servo is controlled to maintain this period as a predetermined value. By multiplying the number of times, it is possible to realize a constant tape speed servo.

G Embodiment G1 Description of one embodiment of this invention G1-1 Description of one example of tape speed detection means FIG. points are taken into account.

The frequency when reproducing the recorded pilot signal is
Since it is very difficult to strictly control this, a deviation with a tolerance of 0.1% (approximately ±100 Hz) is allowed. However, since it is difficult to vary the passing center frequency of the bandpass filter of the pilot signal detection system in accordance with this shift, it was generally undeniable that the S/N ratio would be slightly worse.

Further, in a VTR such as an 8 mm video tape, variable speed playback is often performed by setting the tape speed to a speed different from that during normal playback. In this case, unless correction is made by changing the rotational speed of the rotary head, the relative speed of the rotary head with respect to the tape will deviate from the speed at the time of recording, and the reproduction pilot frequency will also deviate by that amount. For this reason, if the relative velocity deviation of the rotating head is large, the attenuation in the bandpass filter of the pilot signal detection system will be large, and as a result,
This regenerated pilot signal detection system had a disadvantage in that the S/N ratio deteriorated, eventually making detection impossible.

In this embodiment, the pilot signal can be detected with a good S/N ratio without causing the above-mentioned drawbacks without making the relative speed of the rotary head constant.

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.However, as the reference biloft signal, the frequency of the reproduced pilot signal is compared with the reference 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.

(11) is an input terminal to which a playback signal obtained by alternately scanning the tape with HA and HB is supplied, and the signal passing through this input terminal (11) is sent to an RF amplifier (12
) to a bypass filter (13), where the luminance signal is separated from the reproduced color video signal. This luminance signal is supplied to a demodulation circuit (14) and subjected to FM demodulation, and the demodulated output is passed through a low-pass filter (15) and a de-emphasis circuit (16) to a sync separation circuit (17).
A synchronization signal is obtained from this. This synchronization signal is supplied to a half-H killer circuit (18), where it is 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 (19). By the way, in the case of the 8 mm video mentioned above, the pilot signal frequency f1. f2. fi and f< are selected to interleave with the horizontal frequency r of the video signal so as not to affect the video signal, but in general, each signal is obtained by dividing the master clock. There is. For example, in the 8mm video standard (NTSC),
The frequency fM of the master clock is fM = 378f
In H, frequencies f1 to f4 and ΔfA and ΔfB are selected as follows.

f t = f M / 58 = 6.517f H#
102.542kHz f2 = fM/50
= 7.560f H# 118.949kHzf 3
= f M / 36 = 10.500 f H'' =,
165.207kllzf 4-r M/40=
9.450f H#148.686kHzΔfA=f2
f□=1.043fH#16.407kHzΔfA
=f3 f+ = 1.050fH# 16.
521kl (zΔIB=f+f1=2.933
fH#46.144kilzΔfB =f3 f2=
The 2.940fH''q 46.258kHz PLL circuit (19) is used to obtain this master clock MCK, and from this, a master clock MCK with a frequency fM = 378fs that is phase-locked to this horizontal synchronization bus is obtained. Since MCK is phase-locked to the reproduction horizontal synchronizing pulse, its 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 (
201) to (204).

Then, the master clock MCK is input to the frequency dividing circuit (201
), the frequency is divided into 1158, and from this the frequency is 11.
The frequency dividing circuit (202) divides the frequency by 1150 to obtain a signal of frequency f2, and the frequency dividing circuit (203) divides the frequency by 1/36 to obtain a signal of frequency f2. A signal of frequency f3 is obtained, and the frequency dividing circuit (20
In 4), the frequency is divided by 1/40 and the frequency f
4 signals are obtained.

Then, the signal of frequency F+ from the frequency dividing circuit (2(h)) and the signal of frequency "2" from the frequency dividing circuit (202) are switched by the switch circuit (21A), and A signal with a frequency r3 from the circuit (203) and a signal with a frequency f4 from the frequency dividing circuit (204) are switched by a switch circuit (21B). Switching signal I
The IFSW (FIG. 2A) is supplied to the switch circuits (21A) and (21B), so that, as shown in FIG. 2C and D, for example, during the period when the head HA scans the tape, the switch circuit ( A signal of frequency f1 is taken out from the switch circuit (21A), and a signal of frequency f3 is taken out from the switch circuit (21B). During the period when the head HB scans the tape, the switch circuit (21A
), a signal with frequency r2 is sent to the switch circuit (21B).
The signals of frequency 14 are switched so that they are respectively taken out.

The frequency signals from these switch circuits (21A) and (21B) are supplied to multiplication circuits (23A) and (23B), and are multiplied together with a signal of frequency fs, for example, 110 kHz, from a fixed oscillator (24), respectively.

The output signals of the multiplier circuits (23A) and (23B) are supplied to bandpass filters (25A) and (25B), which filter the output signals from the switch circuits (21A) and (23B).
21B) and a signal having a frequency that is the sum of a signal having a frequency rs are obtained.

And these band pass filters (25A) and (2
The output signal of the multiplication circuit (26A) and (26
B).

On the other hand, the reproduced signal through the amplifier (12) is supplied to the bandpass filter (27), and this bandpass filter (
A regenerated pilot signal is obtained from 27), and this regenerated pilot signal is supplied to these multiplication circuits (268) and (26B).

Now, for example, when the head HA is playing on the track rt astride the track T2 on the right, the band pass filter (27) outputs a signal as shown in FIG. 3A, assuming that the tolerance is Δ. Pilot signals with frequencies 1±Δ and f2±Δ are obtained. On the other hand, if a signal with frequency fs+r1±Δ is obtained from the bandpass filter (25A') as shown in FIG. 3B, then the multiplication From the circuit (26A), as shown in Figure 3C, ■(f2±Δ) + (fs +1□±Δ)=ft
+f2 +fs:! :2Δ■ (fs +f,
±Δ) (f2 ±Δ)=fs+ft r2 ■ (rs +f1 ±Δ)+ (f±Δ)=fs
+2(f±Δ) ■ (fs +(1±Δ) Cfx ±Δ)=
Four frequency components of fs are obtained. This multiplication circuit (2
The output of 6A'I is supplied to a narrowband bandpass filter (28A) with a passing center frequency fs, and only the component of frequency fs (2) is extracted therefrom.

The frequency fs component is the frequency f of the reciprocating viroft signal.
1, and has a level corresponding to the level of the reproduced pilot signal of frequency r1.

Similarly, when a signal of frequency fs+f2±Δ is obtained from the bandpass filter (25A), the level corresponds to the level of the signal of frequency r2±Δ contained in the reproduced pilot signal from the bandpass filter (27). A signal with frequency fs is obtained as the output of the multiplication circuit (26A), and this is taken out through the bandpass filter (28A).

That is, the component of frequency [S obtained by this bandpass filter (28^) is nothing but the detected component of the reproduced pilot signal of frequency f1 or frequency f2.

The output of this bandpass filter (28A) is supplied to a level detection circuit (29A) to detect the level of the component of frequency fs, thereby obtaining the detection output SA. 2 Also, multiplication circuit (26B)
The signal of frequency f3 from
When a signal with frequency fs + f3±Δ is obtained from B), it is obtained at a level corresponding to the level of the reproduced pilot signal of frequency f3, and the bandpass filter (25B)
Therefore, when a signal with a frequency fs +f4±Δ is obtained, the signal has a level corresponding to the level of the reproduced pilot signal with a frequency f4. The frequency fs component from this multiplication circuit (26B) is extracted through a narrow band pass filter (28B) with a passing center frequency fs, and is supplied to the detection circuit (29B), where the frequency fs component is extracted. The level is detected and the detected output SB is obtained.

As is clear from the above, the frequency fs component obtained from the bandpass filter (28B>) is the detected component of the reproduced pilot signal of frequency f3 or r4, and the level detection output SB is nothing but the detected level.

Here, in the multiplication circuits (26A) and (26B), the reproduced pilot signal and the outputs of the bandpass filters (25A) and (25B) are multiplied together, and the frequency fs component is obtained as a frequency difference, so the tolerance The amount of Δ is canceled out, and the detected frequency is always fs and does not include the tolerance.

For the same reason, even if the tape speed changes, the relative speed of the rotating head changes, and the frequency of the reproduced signal changes, if the change is seen as Δ, the multiplying circuit (2
6A) (26B) cancels out the change, and tracking error detection is performed using narrow band bandpass filters (28A) and (28B) of frequency rs, and a detection circuit (29).
A) (29B).

Then, the detection output SA of the regenerated pilot signal of frequencies fx and f2, and the detection output SA of the frequency f3. The detection output SB of the regenerated pilot signal of f4 is supplied to the subtraction circuit (30) and output S
Output SB is subtracted from A to obtain subtracted output SD.

The output SD of this subtraction circuit (30) is supplied as it is to one input terminal of a switch circuit (32), and is inverted by a polarity inversion circuit (31) to the other input terminal of this switch circuit (32). Supplied at the end. A signal INV obtained by dividing the head switching signal RFSW from the terminal (22) into 1/2 by a frequency divider (33) is supplied to this switch circuit (32) as a switch control signal. (32) is alternately switched between one input end and the other input end every revolution of the rotary head.

For example, Fig. 2 shows a timing chart during quadruple speed playback, and the switch circuits (21A) and (21B) are switched in the same way as during normal playback based on the head switching signal RFSW (A in the figure). With the sequence shown in Fig. 2 and D, fi + f2 + fff + 4 frequency signals are obtained, respectively. At this time, if the heads HA and HB scan as shown in Fig. 2 J, the reproduced pilot signal will be as shown in Fig. 2 B. Become something.

Therefore, the output SA of the detection circuit (29A) is as shown in figure E, and the output SB of the detection circuit (29B) is as shown in figure F.
The output SD of the subtraction circuit (30) becomes as shown in G in the figure. Therefore, when the switch circuit (32) is switched by the switching signal INV as shown in FIG. A signal with a certain period 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 (32)
As E, at all tape speeds, a signal with a period corresponding to the tape speed is obtained.

Therefore, using this output signal SE, it is possible to apply reel servo at a constant tape speed.

An explanation of an example of the G1-2 reel servo circuit, that is, (4
0) shows an example of the reel servo circuit, and the switch circuit (
The output SE of 32) is shaped into a rectangular wave by a Schmitt circuit (34) and supplied to the reel servo circuit (40). This Schmitt circuit (34) for waveform shaping may be placed immediately after the output of the subtraction circuit (30).

The reel servo circuit (40) in this example includes a monostable multivibrator (41), an integrating circuit (42), and a comparator circuit (43).
).

For example, for the head switching signal RFSW (Fig. 4A), the signal SR of the subtraction circuit (30) (assuming that the waveform has been shaped into a rectangular wave) is as shown in Fig. 4B. Yes, signal INV from frequency divider (33) (C in the same figure)
When the switch circuit (32) is switched and the output SE of this switch circuit (32) becomes a signal as shown in the same figure, the output SE becomes as shown in the figure E rather than the monostable multi-bi break (41). For example, a pulse output SM with a constant pulse width is obtained from the rising point of , and this is supplied to the integrating circuit (42) and integrated to obtain an integrated signal SI as shown in F in the same figure, which is output to the comparator circuit (43). Supplied to one input end.

The voltage ER set by the speed setting variable resistor (44) is connected to the other input terminal of this comparison circuit (43).
45). Then, this comparison circuit (4
3) The voltage difference between the integral output Sl and the set voltage ER is obtained, and this is supplied to the reel stand drive motor (47) via the drive amplifier (46) to drive the tape reel and set the tape speed. The reel stand drive motor (47) is controlled to have a constant speed according to the voltage ER.

In this way, by fast forwarding or rewinding the tape with the reel servo applied at a constant tape speed, the tape can be wound neatly and neatly onto the reel, and there is no need to worry about sudden overloading of the tape. Therefore, damage to the tape is also reduced.

Also, during double-speed playback in the forward direction and double-speed playback in the reverse direction, tape feed speed servo can be performed using the reel stand instead of speed servo using the capstan shaft.

Description of another example of G2 reel servo circuit The reel servo circuit (40) in the example shown in FIG. 1 integrates the tape speed information signal SE and detects the period of this signal SH to obtain speed error information. Similarly to the speed servo circuit in , a ramp wave generation circuit and a sampling hold circuit may be used to obtain the speed error.

Further, a reel servo circuit having a configuration as shown in FIG. 5 may be used.

That is, the tape speed information SEE (A in FIG. 6) from the Schmitt circuit (34) in the example in FIG.
A speed reference oscillator (53) is provided, and a speed reference signal REF (B in the figure) from the speed reference oscillator (53) is supplied to the exclusive OR gate (52). This exclusive OR gate (52) constitutes a phase comparator, and its output EX (C in the same figure) is a phase comparison output and PW
This becomes the M signal. This is smoothed through a low-pass filter (54) as shown in Figure 6, and the smoothed output is supplied to the reel stand drive motor (56) through an amplifier (55). As a result, the motor (56) is operated so that both the tape speed information SEE and the speed reference signal REF are phase-synchronized, that is, the frequencies of both signals match.
is controlled. In other words, the servo is applied to keep the tape speed constant.

Description of another embodiment of the G3 tape speed information detection means The example of the tape speed information detection means described above is a case in which the reproduced pilot signal can be detected with a good S/N ratio even if the relative speed of the rotating head changes. By applying a drum servo that keeps the relative speed of the rotating head constant even when the tape speed changes, the reproduced pilot signal frequency can be converted into voltage and extracted to detect the pilot signal.

Figure 7 is an example of a drum speed servo loop where the relative speed of the rotating head is constant.
A master clock MCK of 781H±Δ (including frequency fluctuations during variable speed playback) is supplied to the frequency detection circuit (62) via the frequency divider circuit (61) to obtain a voltage according to the frequency, which is applied to the drum. The servo is applied so that the frequency supplied to the speed servo circuit (63) and detected by the frequency detection circuit (62) is constant, that is, the relative speed of the rotary head is constant.

When this drum speed servo is applied, the reproduction pilot signal frequency does not change even during variable speed reproduction, so the detection signal of the reproduction pilot signal of frequency f 1 / f 3 and the frequency f 2 /
A two-phase detection signal is obtained with the detection signal of the regenerated pilot signal of f4.

That is, FIG. 8 is an example of the detection system, in which the reproduced pyro is extracted by a bandpass filter (71).

The output signal passes through an amplifier (72) to the frequencies f2 and r.

A regenerated pilot signal of frequency [1 or f3 is obtained from this, which is then supplied to a frequency-voltage conversion circuit (74A) to convert it into a voltage corresponding to the frequency.

In this case, for example, a high level relative to frequency f1.

The conversion characteristics are determined so that a voltage at a low level with respect to the frequency f3 can be obtained from the frequency-voltage conversion circuit 1ffi (74A). This frequency voltage conversion circuit (74A')
The output is supplied to a Schmitt circuit (76A) via a rectifier circuit (75A) and shaped into a rectangular wave 5CA (see, for example, FIG. 9C).

Similarly, the regenerated pilot signal passing through the amplifier (72) attenuates the frequency components of f1 and f3 through the trap circuit (7).
3B), from which a regenerated pilot signal of frequency 2 or f4 is obtained, which is then supplied to the frequency-voltage conversion circuit (74B) and converted into a voltage corresponding to the frequency.In this case, for example, for frequency f2, high level,
The conversion characteristics are determined so that a voltage at a low level with respect to frequency f4 can be obtained from this frequency-voltage conversion circuit (74B). This frequency voltage conversion circuit (74B
) is supplied to the Schmitt circuit (76B) via the rectifier circuit (75B) to generate a rectangular wave SCB (for example, Fig. 9C
(see).

In this way, the output of the Schmitt circuit (768) has a frequency f
1/r] is obtained, and the output of the Schmitt circuit (76B) has a frequency r
A detection signal of the 2/f4 regenerated pilot signal is obtained.

The detection signals of these Schmitt circuits (76Δ) and (76B) are supplied to one and the other input terminals of a switch circuit (77), and this switch circuit (77) is switched by a head switching signal RFSW (Fig. 9A). . The output SCC (for example, see FIG. 9) of this switch circuit (77) is supplied as it is to one input terminal of a switch circuit (78), and is also supplied to the other input terminal via an inverter (79). Then, the head switching signal RFS- is frequency-divided by a frequency divider (80), and the frequency-divided output INV
(FIG. 9F), this switch circuit (78) is switched, and an output signal SCD (for example, see FIG. 9C) having a period corresponding to the tape speed is obtained from this switch circuit (78), and this is transmitted to the amplifier (FIG. 9F). 81) to the output end (82).

By supplying the signal SCD derived from this output terminal (82) to the reel servo circuit (40) of FIG. 1 or the reel servo circuit of FIG. 5, reel servo can be performed at a constant tape speed.

As a means of obtaining tape speed information, when the drum servo is applied so that the relative speed of the rotating head is always constant at all tape speeds as shown in Fig. 7,
The output of a tracking error detection system or similar circuit for 8mm video may also be used. That is, during variable speed playback, the beat components ΔrA and ΔfB undulate at two different periods depending on the tape speed, so the tape speed can be detected from the frequency of this undulation. In this case, the bandpass filter for extracting the beat components ΔfA and Δre needs to have a band slightly wider than the normal band of this filter.

H Effects of the Invention According to the invention, speed servo for feeding the tape using a reel stand is possible even in a rotary head type recording/reproducing apparatus that does not have a fixed head or a control track along the longitudinal direction of the tape.

In addition, in the case of the present invention, since a tracking pilot signal recorded at a long wavelength is detected and utilized, it is possible to detect and utilize a tracking pilot signal recorded at a long wavelength. This increases the margin for hits.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an example of the inventive device, Fig. 2 is a timing chart for explaining its operation, Fig. 3 is a diagram for explaining the operation of a part of the circuit, and Fig. 4 is a part thereof. FIG. 5 is a block diagram of another example of the essential circuit of the present invention, FIG. 6 is a timing chart for explaining the operation, and FIGS. 7 and 8 are timing charts for explaining the operation of the circuit. FIG. 9 is a block diagram of another example of the present invention, FIG. 9 is a timing chart for explaining its operation, and FIG. 10 is a diagram showing an example of a recording trunk pattern on a tape. (26A) and (26B) are multiplication circuits for detecting the reproduced pilot signal, (27) is a bandpass filter for extracting the reproduced pilot signal from the reproduced signal, (28A)
) and (28B) are band pass filters for extracting the detected viroft signal, (30) a subtraction circuit for obtaining a tape speed information output, and (40) a reel servo circuit. 4@Speed ρ1 Timing at birth Luna f11Δ f2+Δ Muna f, standing Δ Saikeito'11 Heavy Kai for each of the 9th (2EA) 1 beak-Ming diagram Fig. 3

Claims (1)

[Claims] 1. An information signal is recorded as a diagonal track by a rotating head, and a plurality of pilot signals having different frequencies are recorded on one track by the rotating head in a state where the frequency can be separated from the information signal. 1 hit
means for obtaining a frequency signal corresponding to the tape speed from a reproduced pilot signal separated from the output of a rotary head for reproduction when reproducing from a tape to which pilot signals of two frequencies are allocated and recorded cyclically; A tape running control device in which a reel stand drive motor is controlled using this frequency signal so that the tape speed is kept constant. 2. The means for obtaining a frequency signal corresponding to the tape speed includes a signal forming means for obtaining a signal of each frequency of the plurality of pilot signals having different frequencies, and a frequency signal from this signal forming means and a signal of a constant frequency. a multiplying means for multiplying the added frequency signal by a reproduced pilot signal; The first
and a second bandpass filter, and subtraction means for taking the difference between the outputs of the first and second bandpass filters, and the tape speed information is obtained from the subtraction means. The tape running control device according to item 1.