JPH0517623B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for detecting the stop position of a magnetic tape, and particularly to a method for detecting the position of a magnetic tape during playback and when the magnetic tape is stopped, in a magnetic recording and reproducing apparatus that records and plays back using a rotating head, such as a video tape recorder. Regarding the method. In a video tape recorder (hereinafter referred to as VTR),
In order to match the magnetic head and video track during playback (track alignment), the rotational position signal of the head drum and the playback control signal (recorded as a pilot signal on the magnetic tape during recording) are compared in phase. A magnetic tape running control servo system is provided that controls the capstan motor with its output. However, in the past, when the magnetic tape was stopped, the relative relationship between the tape stop position and the position of the magnetic head was unknown, so when the magnetic tape started running from a stopped state, the pilot Tracking cannot be performed until the signal is detected, and therefore the pull-in time of the servo system is long. In addition, with a VTR, when continuous shots are taken, the pitch of the magnetic tape pattern may be disturbed at the joint, and the continuity of the pilot signal may be lost. However, in these cases, if the stop position of the magnetic tape relative to the rotating head is detected when the magnetic tape is stopped, the detection signal is used to shorten the pull-in time of the servo system when moving to the next running state. It would also be possible to maintain the continuity of the pilot signal in continuous shooting. Therefore, a main object of the present invention is to provide a magnetic tape stop position detection method that can detect the stop position of a magnetic tape in a stopped state. To summarize the invention, first, second, third and fourth pilot signals, which are generated in synchronization with the rotation of a rotating magnetic head of a magnetic tape and have mutually different frequencies, are multiplexed onto a video signal to be recorded in sequence. When the magnetic tape is recorded and the magnetic tape is stopped, the first and second signals are extracted from the pilot signal included in the signal reproduced by the rotary head and a reference pilot signal that is different from the reproduced pilot signal. Generate and detect a beat signal, compare each detected signal to output a first comparison signal, and compare the other pilot signals included in the reproduced signal with the reproduced pilot signal and the reference. Generate and detect third and fourth beat signals from a reference pilot signal different from the pilot signal, compare the respective detected signals, output a second comparison signal, and switch the rotating head. The magnetic tape is configured to generate a signal indicating a stop position of the magnetic tape in response to a head switching signal, a signal representing the passage of time that is reset in synchronization with the head switching signal, and the first and second comparison signals. This is what I did. The above objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings. FIG. 1 is a diagram schematically showing the positional relationship between a magnetic tape and a magnetic head. First, the relationship between the video track on the magnetic tape surface and the travel locus of the magnetic head will be explained with reference to FIG. Video tracks 2a, 2 on magnetic tape 1
2b, 2c, 2d, and the magnetic head 3a (the magnetic head 3b is not shown) when the magnetic tape 1 is in a stopped state. The magnetic tape 1 is inserted into the magnetic head 3a,
3b is assumed to run in the direction shown by arrow B, and the track widths of video tracks 2a to 2d are T,
Let W be the head width of the magnetic heads 3a and 3b, and P be the track pitch in the longitudinal direction of the magnetic tape 1. The running trajectory of the magnetic heads 3a and 3b is
Travel locus 4 of the lower end, upper end and center of a and 3b
It shall be expressed using a, 4b, and 4c. It should be noted that pilot signals _f1 to _f4 are sequentially recorded on the video tracks 2a to 2d by being multiplexed with the video signal, and the video tracks 2a and 2c and the video tracks 2b and 2d are recorded by the same magnetic head, respectively. , these two magnetic heads have different azimuths from each other. Switching points 5a, 5 for the magnetic heads 3a, 3b during playback are located near both ends of the magnetic tape 1.
b are set respectively. The stop position of the magnetic tape 1 is set by the magnetic heads 3a, 3.
Center travel locus 4c of b and switching point 5
Now, the X coordinate of the magnetic tape 1 is taken as the longitudinal direction, and the zero point is the point where the central traveling locus 4c of the video track 2d intersects with the switching point 5a. The stop position of the magnetic tape 1 shown in FIG. 1 is at x=1.9p. Since the video tracks 2a to 2d are recorded periodically with respect to the pilot signals _f1 to _f4 , with four tracks as one cycle, by using the pitch p,
=0 to 4p can represent all stop positions. The pilot signals f ₁ to _{f 4} are signals each having a different constant frequency in a frequency range lower than that of the low frequency conversion color signal, and between the mutual frequencies |f ₁ −f ₂ |
≒｜f ₀ −f ₄ ｜=f _A , |f ₁ −f ₄ ｜≒｜f ₂ −f ₃ ｜=f _B , f _A
It is a signal of approximately 102kHz to 200kHz that satisfies the condition ≠f _B. For example, f ₁ , f ₂ , f ₃ , f ₄ are 100kHz in order,
118kHz, 164kHz, and 148kHz have been proposed. Further, the frequency difference f and f are several tens of kHz (in the above example, they are 16 kHz and 46 kHz, respectively). As mentioned above, since the pilot signals f ₁ to _{f 4} have lower frequencies than the video signals, the influence of the azimuth effect of the magnetic heads 3a and 3b is small, and reproduction is possible even with magnetic heads having an azimuth different from that during recording. be. Regarding the stop magnetic tape 1 as described above, the second
Figure a shows the stop position of the magnetic tape 1, i.e. x=
1.9p, the reproduction track widths T ₁ and T ₃ of the video tracks 2a and 2b traced by the magnetic heads 3a and 3b during one field period are shown. Here, the playback track width means the width of the overlapping portion between the magnetic head and the video track. In the figure, the horizontal axis is the time t normalized by one field time t _f , and t/t _f =0.1 is the magnetic head 3
This corresponds to the time when the centers of the heads of a and 3b pass through the switching points 5a and 5b. Further, in the figure, the head width W of the magnetic heads 3a and 3b is designed to be 1.6 times the track width T.
FIG. 2b shows the reproduction track widths T ₂ and T ₄ of the video tracks 2b and 2d at the same magnetic tape stop position as in FIG. 2a. In the same figure,
At the time when t/t _f =0.9, the values of the reproduced track widths T ₂ and T ₄ match, and the magnitude relationship is reversed. As can be seen from the examples shown in FIGS. 2a and 2b, there are two playback track widths T ₁ , T ₃ and T ₂ , depending on the magnetic tape stop position.
The T ₄ relationship has a unique magnitude relationship. Figure 3 shows the magnitude relationship of the reproduction track widths T ₁ and T ₃ and the magnitude relationship of T ₂ and T ₄ in one field period with respect to the stop position x of the magnetic tape based on the above definition. be. Here, 0<x<
The area of p is X ₁ , the area of p≦x≦2p is X ₂ , 2p<x
Let the region <3p be X ₃ and the region 3p≦x≦4p be X ₄ . As is clear from the figure, when comparing the two sets of reproduction track widths T ₁ and T ₃ and T ₂ and T ₄ during one field period, in any of the regions X ₁ to _{X 4} , one set is There is a set in which the size relationship of the playback track width is not reversed, and by knowing the size of the playback track width in this set that is not reversed, it is possible to determine whether the stop position x of the magnetic tape is in the area _X1 , _X2 , _X3 , or _X4. It is possible to determine whether there is for example,
When comparing playback track widths T ₁ and T ₃ , T ₁ is always
If T is ₃ or more, the stop position x of the magnetic tape is area X ₂
, and if T ₁ is always less than or equal to T ₃ , the stop position x
is in territory X ₄ . Alternatively, by knowing the magnitude relationship of the playback track width and the presence or absence of the point at which the magnitude relationship is reversed, the stop position x of the magnetic tape 1 _can be set to
It is also possible to determine which region of X ₄ it is in. However, in FIG. 3, in area X ₂ ,
At the timings of (x=p, t=t _f ) and (x=2p, t=0), the playback track width becomes T ₁ =T ₃ , and (x=p, t=0) and (x=2p ,t=
t _f ), the playback track width becomes T ₂ =T ₄ . Also in area X ₄ , when (x=3p, t=t _f ) and (x=4p, t=0), the playback track width is T ₁ =
T ₃ , (x=3p, t=0) and (x=4p,
When t=t _f ), the reproduction track width becomes T ₂ =T ₄ . Here, since the pilot signals f ₁ , f ₂ , f ₃ , and f ₄ are written superimposed on the video track, the reproduction track widths T ₁ , T ₂ , T ₃ , and T ₄ are the same as those of the magnetic head 3.
Pilot signal included in the reproduced signals of a and 3b
It has a proportional relationship with the amplitude of f ₁ , f ₂ , f ₃ , and f ₄ respectively. This invention provides the above-mentioned proportional relationship between the reproduction track width and the amplitude of the pilot signal, and the first
The stop position x of the magnetic tape 1 and the playback track widths T ₁ , T ₂ ,
The position of the magnetic tape is detected using the correspondence between T ₃ and T ₄ . FIG. 4 shows the relationship between the stop position x of the magnetic tape and the time t _x at which the magnitude relationship between the reproduction track widths T ₁ and T ₃ or T ₂ and T ₄ is reversed. In addition,
t _x is the time when the starting point of the field is set to 0. What this figure 4 means is that each area
This means that t _x differs depending on the stop position within X ₁ to X ₄ , and the relationship between the stop position within the area and t _x is expressed at the same rate in any of the areas X ₁ to X ₄ . . Therefore, if the same reference voltage is generated in any region as shown in Fig. 4 and the reference voltage value at t _x is extracted, the position within the region can be determined by the extracted voltage value. You can also know. In this way, it is possible to know not only which of the regions _X1 to _X4 the magnetic tape is located, but also the position within that region, which makes it possible to know the exact stop position of the magnetic tape, which is even more effective. In addition, when the stop position x is x=P, 2P, 3P, 4P, there is no point at which the magnitude relationship of the reproduction track widths is reversed, so in this case, from the relationship shown in Table 1, the value of x is It is possible to detect whether it is P, 2P, 3P, or 4P. This Table 1 provides supplementary explanation for the case where x in FIG. 3 has the above four values. From this table, it can be determined that x=P, for example, if there is no reversal of the reproduction track width and T ₁ ≧T ₃ and T ₂ ≦T ₄ .

[Table] FIG. 5 is a block diagram of an embodiment of the present invention. First, the configuration of the main parts in FIG. 5 will be explained. A reproduction signal of the rotating magnetic heads 3a, 3b including a pilot signal is inputted from an input terminal 28. This reproduced signal is transmitted to balanced modulators 6a and 6b.
given to. The balanced modulator 6a has an input terminal 2.
_A beat signal of _{frequency f A or f B} ( _hereinafter referred to as beat signal f _A , f _B ) is formed. The output signal of the balanced modulator 6a is input to band filters 7a and 7b whose center frequencies are respectively set to the frequencies f _A and f _B of the beat signal, and the beat signal component included in the output signal of the balanced modulator 6 a is are separated. isolated beat signal
f _A and f _B are respectively detected by detectors 8a and 8b into signals having corresponding amplitudes, which are applied to an input terminal of a comparator 9a to compare the levels between the two input signals. Comparator 9a provides a high level or low level signal to pulse generator 10a based on the comparison result. The pulse generator 10a generates positive pulses at the rise and fall of the input signal and applies them to the trigger terminal T of the D-type flip-flop 11a. Moreover, the input terminal 30 is connected to the other balanced modulator 6b.
The pilot signal f ₂ input to is given. Then, the balanced modulator 6b generates a beat signal f A or _{f B} between the pilot signals f ₁ , f ₃ and the pilot signal f ₂ included in the reproduced signal, and this beat signal f _A
Or f _B is band filter 7c and 7d, detector 8c
and 8d to the comparator 9b. Comparator 9b
The output of is applied to the pulse generator 10b, which generates a positive pulse and applies it to the trigger terminal T of the D-type flip-flop 11b. A head switching signal HS _w is input to the input terminal 31 . This head switching signal HS _w is applied to a trigger terminal T of a D-type flip-flop 18 via a pulse generating circuit 17 . A detection command is input to the input terminal 32, and this detection command is applied to the reset input terminals of the D-type flip-flops 11a, 11b and 18 as a reset signal. The output of the D-type flip-flop 18 is input to a triangular wave generating circuit 19 which generates a triangular wave signal. The triangular wave signal generated by the triangular wave generating circuit 19 is given to a sample hold circuit 22. Sample hold circuit 2
2 will be explained in detail in the operation explanation below, but
The output of the AND gate 21 is used as a sampling pulse to sample and hold a triangular wave signal. FIG. 6 is a timing diagram for explaining the operation of FIG. 5. Next, the specific operation of one embodiment of the present invention will be explained with reference to FIGS. 1 to 6. As shown in FIG. 6a, time t=t ₀
Assume that a stop position detection command is issued in .
Before this time, D-type flip-flops 11a, 1
1b and 18 are in a reset state, and their respective output terminals Q are at a low level. The balanced modulator 6a outputs the second and fourth pilot signals among the four pilot signals included in the reproduced signal.
The respective frequencies generated by f ₂ and f ₄ and the separately input pilot signal f ₁ of constant amplitude output signals containing the beat signals f _A and f _B as described above. Here, the amplitudes of the beat signals f _A and f _B match the amplitudes of the pilot signals f ₂ and f ₄ included in the reproduced signal. Note that the above-mentioned reproduced signals are obtained by amplifying the signals reproduced by the rotating magnetic heads 3a and 3b, and then converted into pilot signals f ₁ , f ₂ , f ₃ and f ₄ .
The signal may be passed through a filter having a passband within the passband, and this has the advantage of not being undesirably influenced by video signals or the like. Band filters 7a and 7b separate and detect beat signals f _A and f _B from the output of balanced modulator 6a, respectively, and detectors 8a and 8b output the amplitudes of the respective signals. The outputs of the detectors 8a and 8b are input to a comparator 9a, and the magnitudes thereof are compared.
Similarly, the balanced modulator 9b has the first and third
beat signals f _{A , f B are} output based on the pilot signals f ₁ , f ₃ and the separately input pilot signal f ₂ , and the band filters 7c, 7d output the beat signals f _A , f _B
Separate. Detectors 8c and 8d detect beat signals f _A ,
The amplitude of f _B is output and compared by comparator 9b. In this case, the beat signals f _A and f _B are pilot signals whose amplitudes are included in the reproduced signal.
This corresponds to the magnitude of the amplitudes of f ₁ and f ₃ . When the stop position of the magnetic tape 1 is x = 2.5P, the detector 8
The outputs of a to 8d change as shown in c to f of FIG. 6. At this time, the output of the comparator 9a is always at a high level as shown in FIG.
After the values of the outputs of 8d match, the time point when the magnitude relationship is reversed (for example, at time t=
t ₂ ) and at the start of the field (e.g. 6th
In the figure, it is reversed at time t=t ₁ ). Incidentally, FIG. 6b shows a head switching signal for switching between the rotating magnetic heads 3a and 3b. Now, in synchronization with the inversion of the output of the comparator 9b at t= _t1 , the pulse generator 10b generates a pulse of positive polarity, and this pulse triggers the D-type flip-flop 11b, and the data terminal D
The high level signal input to the output terminal Q is outputted to the output terminal Q. On the other hand, the output terminal Q of the D-type flip-flop 11a remains at low level. At this time, the first and second output terminals 33, 3
The output signals O ₁ and O ₂ generated at the output terminal 4 are both at high level. In the embodiment shown in FIG. 5, information indicating which of the regions X1 to _X4 the rotating magnetic heads 3a and _3b are located (i.e., the rough stop position of the magnetic tape) is provided by the output signal _O1 shown in Table 2. , O ₂ . Therefore, the output signal O ₁ ,
If both _O2 levels are high, it is determined that the magnetic tape stop position is in area _X3 .
In this way, in the embodiment shown in FIG.
The approximate stopping position of the magnetic tape can be determined from the binary information of O ₁ and O ₂ . Note that it is not necessary to divide the area into four areas, X ₁ to X ₄ .
For example, there may be two areas. In Table 2, cases in which the output signals O ₁ and O ₂ are different from each other (i.e., high level and low level, and low level and high level) are treated as one area, and cases in which they are the same (i.e., high level, high level) are treated as one area. (low level, low level case) may be grasped as one other area. This can be easily realized by connecting, for example, an exclusive OR circuit after the first and second output terminals 33 and 34. Furthermore, the present invention is not limited to the above-mentioned embodiment, and it may be possible to grasp the information using more than four regions. As described above, the stop position of the magnetic tape is detected in units of areas defined in the longitudinal direction of the magnetic tape, and this detection signal can be used for various purposes as required. Next, a method for more accurately determining the stop position of the magnetic tape, rather than in units of areas, will be explained with reference to FIGS. 5 and 6. Even in that case, the aforementioned output signals O ₁ and O ₂ are necessary, and by obtaining a signal indicating the position in the area represented by these output signals O ₁ and O ₂ , the reflective The exact stopping position can be determined. In FIG. 5, the output of the exclusive OR circuit 14b goes from a high level to a low level in synchronization with the point in time when the values of the outputs of the detectors 8c and 8d match and their magnitude relationship is reversed, as shown in FIG. 6l. Flip to level. The pulse generator 15b generates positive pulses in synchronization with the rise and fall of the output of the exclusive OR circuit 15b. As mentioned above, since the output terminals Q of the D-type flip-flops 11a and 11b are at low level and high level, respectively, the NAND circuit 20
outputs the output of the above-mentioned pulse generator 15b as is. Output terminal Q of D-type flip-flop 18
is synchronized with the rise or fall of the first head switching signal HS _w (Fig. 6b) after the detection command is output, that is, in Fig. 6, time t = t ₁
It changes from low level to high level when , and thereafter the low level and high level are repeated with two fields as one cycle. The triangular wave generator 19 is shown in Fig. 6 p.
As shown in the figure, the potential increases from Va at a constant amplification factor (Vb - Va)/t _f in synchronization with the rise of the Q terminal output of the D-type flip-flop 18, and in synchronization with the fall of the Q terminal output mentioned above. outputs a signal whose potential decreases as it moves from Vb to Va. The sample and hold circuit 22 is configured as shown in FIG.
The triangular wave generator 1 uses the output of the AND circuit 2, which is the AND of the output of the NAND circuit 21 and the Q terminal output of the D-side flip-flop 18, as a sampling pulse.
The output of 9 is sampled and held, and the potential V is output. Here, as is clear from the correspondence with FIG. 4, when x=2.5P, the potential V is V=(Va+
Vb)/2. Since the control terminal C of the switch circuit 24 is at a high level, the output of the sample hold circuit 22 connected to the input terminal 1b, that is, the potential V is outputted to the third output terminal 35. The above explanation is for the case where x=2.5P, but if x is in the region _X3 , the embodiment shown in FIG. 5 operates in the same way, and the output signal _O1 becomes high level The output signal O ₂ also becomes high level,
The potential of output _O3 is Va+(X-2P)×(Vb-Va)/P
becomes. As is clear from FIG. 55 and FIG. 6, in this embodiment, regardless of the timing at which the stop position detection command is issued, the output signals O ₁ and O ₂ are output one field time after the detection command is issued. As for the output signal _O3 , the above-mentioned stop position information is output after two field times. Stop position x is area X ₁ or area X ₂ excluding x = P, 2P or area X ₄ excluding x = 3P, 4P
, compare the outputs of the detectors 8a and 8b or the outputs of the detectors 8c and 8d,
There is a point in time when the magnitude relationship is reversed in either the combination of the outputs of the detectors 8a and 8b or the combination of the outputs of the detectors 8c and 8d, and the output signals O ₁ ,
The signals shown in Table 2 are obtained for O ₂ and O ₃ . Here, x=P, 2P, which was excluded in the above explanation,
The output signal _O3 in the case of 3P and 4P will be explained.
The outputs of comparators 9a and 9b are both fixed at high level or low level and are not inverted, so the Q terminal outputs of D-type flip-flops 11a and 11b both remain at low level. At this time,
The control terminal C of the switch circuit 24 is at a low level, and the input terminal Ia is connected to the third output terminal 35. On the other hand, the input terminal Ia is connected to the output terminal of a second switch circuit 27, which is controlled by the outputs of the comparators 9a and 9b at its control terminal C'. Exclusive
The output of the OR gate 26 is given, and when the output is high level, it is set to the lower side, and when it is low level, it is set to the upper side, and the comparators 9a and 9b are set to the high level or low level according to the relationship explained in Table 1. As a result, the output of the third output terminal 35 is
For O ₃ , if x=P, 3P, Va is derived, x
= 2P, 4P, Vb will be derived.
In addition, fixed Va and Vb in this case are resistors R1 and R
It is generated by connecting 2 and R3. As described above, the output signal O ₃ shown in Table 2 is obtained also at each point of x=P, 2P, 3P, and 4P. To summarize the above explanation, in the embodiment shown in FIG. 5, as shown in Table 2 below, depending on the high level and low level of the output signals O ₁ and O ₂ ,
The stop position x of the magnetic tape 1 is in the areas X ₁ , X ₂ , X ₃ ,
X ₄ can be detected, and furthermore, the value of x can be detected from the potential of the output signal O ₃ .
In the embodiment shown in FIG. 5, pilot signals f ₁ and f ₂ are used as the reproduction signal and the beat signal, but other combinations, namely f ₁ , f ₄ , and f ₃ are used.
Similar detection is also possible using f ₂ , f ₃ and f ₄ .

[Table] Note that by taking the beat using a signal formed separately from the reproduced signal in this way, the frequency of the comparison signal can be lowered, and the band filters 7a and 7c and 7b and 7d can each have the same frequency. It gives you the advantage of being able to use things. Furthermore, using the pilot signal as the signal for taking the beat is because the pilot signal itself is prepared in the VTR as a signal to be multiplexed with the video signal and recorded, so it is necessary to use a pilot signal other than the pilot signal oscillation circuit. This has the advantage that there is no need to provide a special oscillation circuit. Furthermore, in the embodiment shown in FIG. 5, the comparison between pilot signals f ₁ and f ₃ included in the reproduced signal _and
Although comparisons of f and _f4 are performed in parallel, the same detection can be achieved even if both are performed sequentially. If the process is performed sequentially, only one comparator is required. As described above, according to the present invention, when the magnetic tape is reproduced and stopped, the pilot signal included in the signal reproduced by the rotary head and the reference pilot signal different from the reproduced pilot signal are extracted. The first to fourth beat signals are generated and detected, the respective detected signals are compared to output first and second comparison signals, and the head switching signal, a signal representing the passage of time, and the first and second comparison signals are output. Since the signal indicating the stop position of the magnetic tape is generated in accordance with the second comparison signal, the stop position of the magnetic tape can be easily known. Therefore, if this invention is used, it will be effective in shortening the pull-in time of the magnetic tape running control servo system, maintaining the continuity of pilot signals during splicing, and controlling magnetic tape feeding to obtain noiseless still images. . Moreover, since the beat signal is generated from the pilot signal, there is no need to provide a separate oscillation circuit other than the pilot signal generation circuit.

[Brief explanation of the drawing]

FIGS. 1, 2, 3, and 4 are diagrams for explaining the relationship between the magnetic tape stop position and the pilot signal included in the reproduction signal, which are related to the present invention. FIG. 5 is a block diagram showing an example of a circuit implementing the method according to the invention. FIG. 6 is a timing diagram for explaining the operation of FIG. 4. In the figure, 1 is a magnetic tape, 2a, 2b, 2
c, 2d are video tracks, 6a, 6b are balanced modulators, 7a, 7b, 7c, 7d are band filters,
8a, 8b, 8c and 8d are detectors, 9a and 9b are comparators, 19 is a triangular wave generator, 22 is a sample and hold circuit, and 24 and 27 are switch circuits.

Claims (1)

[Scope of Claims] 1. Four pilot signals, first, second, third, and fourth, which are generated by a rotating head in synchronization with its rotation and have mutually different frequencies, are sequentially converted into video signals to be recorded. In a magnetic recording and reproducing apparatus that multiplexes recording onto a magnetic tape and reproducing it, a pilot signal included in the signal reproduced by the rotary head and a reference pilot signal different from the reproduced pilot signal are extracted. generating and detecting first and second beat signals, comparing the respective detected signals to output a first comparison signal, and comparing other pilot signals included in the signal reproduced by the rotary head; Then, third and fourth beat signals are generated and detected from this reproduced pilot signal and a reference pilot signal different from the reference pilot signal, and the respective detected signals are compared to perform a second comparison. output a signal, and perform playback in response to a head switching signal for switching the rotating head, a signal representing the passage of time that is reset in synchronization with the head switching signal, and the first and second comparison signals. A method for detecting a stop position of a magnetic tape, further comprising generating a signal indicating a stop position of the magnetic tape when the magnetic tape stops. 2. Claim 1, characterized in that the first and second comparison outputs are obtained sequentially.
2. Method for detecting stop position of magnetic tape as described in . 3. The magnetic tape stop position detection method according to claim 1, wherein the first and second comparison outputs are obtained simultaneously. 4. The device according to any one of claims 1 to 3, characterized in that when comparing the amplitudes of the pilot signals, pilot signals separately detected from the reproduction signal of the magnetic head are used. A method for detecting the stop position of a magnetic tape.