JPH02146139A - Tape reproducing device - Google Patents

Abstract

PURPOSE:To maintain tape speed at a desired constant value in simple constitution without detecting tape traveling speed by traveling a tape at high speed interlocking with a control for rotating a drum at high speed upon a request of a high speed reproducing of the tape. CONSTITUTION:When the request of the high speed reproducing of the tape is made, an FG signal frequency corresponding to the speed of the drum 16 to be outputted from an FG pattern detecting part 28 and a frequency of a drum motor high speed detecting speed designation signal for designating the high speed rotation of the drum 16 are compared with each other by a servo circuit 26. Then, the FG signal frequency and the designation signal frequency are made identical. That is, a motor 18 is controlled in its speed to be accelerated. When the tape speed is gradually increased, the speed of a drum motor 27 is gradually increased by a drum servo circuit 33. By this method, the tape traveling speed can be maintained at the desired constant value is simple constitution without detecting the tape traveling speed.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a helical scan type tape playback device such as a rotary head type digital audio tape recorder, and particularly to a high-speed search thereof. This invention relates to improved high-speed playback means applied to functions, etc.

(Prior Art) As is well known, in the field of audio equipment, in order to record and reproduce information with as high density and high fidelity as possible, PCM (Pulse Code Modulation) technology is used to process information signals such as audio signals. Digital recording and reproducing systems that convert data into digitized data, record it on a recording medium, and reproduce it have become popular.

Among these, those that use magnetic tape as a recording medium are called digital audio chip recorders.
For example, there are fixed head types with multiple heads arranged in the width direction of the tape, and helical scans in which the tape is wound around a cylindrical drum with heads that rotate along the circumference. There is also a rotating head type.

Here, a rotary head type digital audio recorder is generally provided with a high-speed search function as its characteristic function. This high-speed search function uses a high-speed playback function that reads positional information recorded on a tape while running the tape at high speed to search for desired data at high speed.

By the way, in order to perform the above-mentioned high-speed playback, if the rotational speed of the drum is kept in the normal playback state (2000r, I), m,) and only the running speed of the tape is increased, the playback data will change in proportion to the tape running speed.・The rate will change. For example, if the tape is run at 200 times the speed in the normal playback direction, the playback data rate will be approximately 1/2 that of normal playback.

Additionally, if the tape is run at 200 times the speed in the opposite direction to normal playback, the playback data rate will be approximately 3 times that of normal playback.
/2.

In other words, when performing high-speed playback at 200 times the speed of normal playback, the playback data rate is 1/2 to 1/2 of normal playback.
In order to cope with this change, the waveform of the reproduced signal obtained from the head is supplied with a wider band, or the reproduction data rate is changed in accordance with the change in the reproduction data rate. Therefore, countermeasures such as switching the frequency characteristics are required. Furthermore, it is necessary to use a circuit capable of high-speed processing as a processing circuit for the reproduced digital signal.

Therefore, conventionally, by changing the rotational speed of the drum in accordance with the running speed of the tape, it is possible to obtain the same playback data rate as during normal playback even during high-speed playback, without changing the circuit system. (
constant data rate control) is being considered.

As means for performing this constant data rate control, there are two methods: specifying the tape running speed and the drum rotational speed and controlling both independently; or specifying only the tape running speed and controlling the drum speed. A known method is to run the drum at high speed and control the rotational speed of the drum so that the output rate of the obtained reproduction signal is constant.

FIG. 4 shows a conventional high-speed reproduction means in which the rotational speed of the drum is made to follow the running speed of the tape so that the data rate of the reproduction signal is constant.

That is, in the figure, 11 is a main chassis, which includes a pair of reel stands 12, 13, heads 14, . A drum 16 and a capstan 17 having a diameter of 15 are each rotatably supported.

Among these, the capstan 17 is directly connected to the rotating shaft of the motor 18 and driven to rotate. Further, an FG pattern (not shown) is formed around the rotation axis of the motor 18, and the FG pattern detection section 19 can obtain an FG multiplied signal corresponding to the rotation speed. Furthermore, the rotational force of the motor 18 is selectively transmitted to the reel stand 12, 13 via a pulley 20 and a gear section 21.

Further, the reel stand 12.1g has an FG pattern (not shown) formed around its rotation axis,
Each reel stand 12 is detected by the FG pattern detection unit 22.23.
．． The FG multiplied signal corresponding to the rotation speed of 13 can be obtained. Then, this FC pattern detection section 22.2
Each FG multiplied signal output from 3, tape speed detector 24
is supplied to

The tape speed detector 24 calculates the tape running speed based on each input FG multiplied signal and generates a speed detection signal corresponding to the calculated tape running speed.

The speed detection signal output from the tape speed detector 24 and the FC pattern detection section 19 of the motor 18 are
The FC signal output from the motor 1 is selectively supplied to the motor servo circuit 26 by the changeover switch 25, and
8 rotation speed control.

On the other hand, the drum 16 is directly connected to a rotating shaft of a drum motor 27 (which overlaps the drum 16 in the figure) and is rotationally driven. Further, an FG pattern (not shown) is formed around the rotation axis of the drum 16, and the FG pattern detection section 28 can obtain an FG multiplied signal corresponding to the rotation speed.

Further, the reproduced signals obtained from the heads 14 and 15 are supplied to a digital signal processing system (not shown) after passing through a head amplifier 29 and an equalizer circuit 30, and are also supplied to a reproduced data rate detector 31. The reproduction data rate detector 31 detects the data rate of the input reproduction signal and outputs a data rate detection signal.

The data rate detection signal outputted from the reproduced data rate detector 31 and the FG of the drum 16 are
The FG multiplied signal output from the pattern detection section 28 is selectively supplied to the drum servo circuit 33 by the changeover switch 32, and is used to control the rotational speed of the drum motor 27.

In the above configuration, first, during normal playback, the selector switch 25 is switched to the FG pattern detection unit 19 side, and an FG double signal corresponding to the rotational speed of the motor 18 is supplied to the motor servo circuit 26. At this time, the motor servo circuit 26 is supplied with a motor 18 corresponding to the tape running speed during normal playback from a microcomputer (not shown) that controls the operation of the digital audio chip recorder.
A motor rotation speed designation signal is supplied that designates the rotation speed of the motor.

Then, the motor servo circuit 26 controls the rotational speed of the motor 18 so that the frequency of the FC signal obtained from the FG pattern detection section 19 matches the frequency of the motor rotational speed designation signal. The vehicle is controlled to run at a constant speed corresponding to playback.

On the other hand, the changeover switch 32 is connected to the FG pattern detection section 2.
F corresponding to the rotational speed of the drum 16.
The G multiplied signal is supplied to the drum servo circuit 33. At this time, the drum servo circuit 33 is supplied with a drum motor rotation speed designation signal that designates the rotation speed of the drum 16 during normal playback from the above-mentioned microcomputer.

Then, the drum servo circuit 33 controls the rotational speed of the drum motor 27 so that the FG multiplied signal frequency obtained from the FG pattern detection section 28 matches the frequency of the drum motor rotational speed designation signal. te is controlled so that it is rotated at a constant speed corresponding to normal playback.

Next, during high-speed reproduction, the selector switch 25 is switched to the tape speed detector 24 side, and a speed detection signal corresponding to the tape running speed is supplied to the motor servo circuit 26. Here, the tape speed detector 24 calculates the tape running speed by calculating the following equation.

n meeting Vnt − (4 yrl) δ+2 yr r 2)
/ l (N/ f t) 2 + (N/ f s) 2 However, n is the tape speed number, Vnt is the tape running speed during normal playback, g is the tape length, and δ is the tape speed. thickness, and r is the radius of the reel stand (both reel stands 12
．． 13 are the same), N is the maximum of the FG pattern formed on the reel stand (same number on both reel stands 12 and 13), and ft is the FG pattern obtained from the FG pattern detection unit 23 of the take-up reel stand 13. This is the double signal frequency, and fs is the frequency of the FC signal obtained from the FG pattern detection section 22 of the supply side reel stand 12.

In the right-hand side of the above equation, variables other than ft and fs become constant once the tape and the digital audio recorder that plays it are determined. Therefore, the tape speed detector 24 calculates the tape running speed n5Vnt by inputting only ft and fs.

Further, the motor servo circuit 26 is supplied with a motor high speed rotation speed designation signal from the microcomputer that designates the rotation speed of the motor 18 corresponding to the tape running speed during high speed playback. And motor servo circuit 2
6 controls the rotational speed of the motor 18 so that the frequency of the speed detection signal obtained from the tape speed detector 24 matches the frequency of the motor high-speed rotational speed designation signal, which corresponds to when the tape is played at high speed. The vehicle is controlled to run at a high speed.

On the other hand, the changeover switch 32 is switched to the reproduction data rate detector 31 side, and a data rate detection signal is supplied to the drum servo circuit 33. At this time, the drum servo circuit 33 is supplied with a reproduction data rate designation signal for designating the reproduction data rate during normal reproduction from the above-mentioned microcomputer.

Then, the drum servo circuit 33 controls the rotational speed of the drum motor 27 so that the frequency of the data rate detection signal matches the frequency of the reproduction data rate designation signal. The rotational speed of the drum 16 is controlled so that the rotation speed of the drum 16 is the same as that during normal reproduction.

Here, FIG. 5 shows the relationship between the head 14 and the helical track (data recording pattern) T formed on the tape 34 when the data rate constant control as described above is performed.
．． 15 trajectories are shown. That is, when the tape 34 is running at high speed in the same direction as during normal playback, that is, in the direction of arrow a, if the tape running speed is slow, the trajectory of the head 14.15 becomes as shown by the arrow in the figure, and the tape running speed is When the speed is high, the trajectories of the heads 14 and 15 become as shown by arrow C in the figure.

In short, the angles θl and θ2 formed by the moving direction of the head 14, 15 and the running direction of the tape 34 become larger as the tape running speed becomes faster. As you can see, it is much shorter.

By the way, each track T is formed in a format as shown in FIG. 6(a). In addition, Fig. 6 (a
) are indicated by numbers 1 to 16 in the same figure (b
) is the recording area for the data shown. Of these, the position information necessary for high-speed search is stored in subcode areas 5UB-1 and 5UB-2 consisting of 8 blocks.
It is recorded so that it can be completed in one block. Further, the digitized data of the audio component is recorded in a data area PCM consisting of 128 blocks.

As shown in FIG. 7, one block is composed of an 8-bit 5YNC area, an identification code area, a block address area, a parity area, and a 256-bit data area.

Therefore, in order to read the necessary position information during a high-speed search, it is necessary to completely read at least one block of either subcode area 5UB-1 or 5UB-2 from the beginning to the end. Furthermore, during a high-speed search, the position in the block at which data reading starts cannot be guaranteed, so it is necessary to trace a distance of at least two blocks within the same track T.

Therefore, it is necessary to set an upper limit on the tape running speed so that the distance of tracing the same track T is not shorter than the distance of two blocks.

Therefore, the search time can be shortened most by running the tape 34 constantly at the above-mentioned upper limit speed from the start to the end of the high-speed search operation.

However, in the conventional tape playback device as described above, in order to keep the tape running speed constant at the upper limit speed at which two blocks of the same track T can be read, the tape speed detector 24 has to operate as shown in the above equation. It is necessary to perform such complex calculations at high speed, resulting in a problem that the configuration becomes complicated and large, which is economically disadvantageous. In particular, since the tape running speed must be calculated in real time, an expensive microcomputer capable of high-speed processing must be used.

In addition, when calculating the tape running speed, tape-specific parameters such as tape length and tape thickness are used, so unless you reset the settings every time you change the tape, you will not be able to accurately calculate the tape running speed. This is something that cannot be done. Furthermore, since the rotational speed of the reel stands 12, 13 is detected using the FC pattern, there is also the problem of complicating the configuration and increasing the size.

(Problems to be Solved by the Invention) As described above, in conventional tape playback devices, the calculation of the tape running speed is complicated and the circuit becomes large. It is also necessary to separately provide this, which poses a problem of being economically disadvantageous.

Therefore, this invention was made in consideration of the above circumstances, and it is possible to maintain the tape running speed at a desired constant value during high-speed playback without detecting the tape running speed, and the structure is simple and compact. It is an object of the present invention to provide an extremely good tape reproducing device that is suitable and economically advantageous.

[Structure of the Invention] (Means for Solving the Problems) A tape playback device according to the present invention performs helical scanning by bringing a tape into contact with the peripheral surface of a drum having a head, rotating the drum and running the tape. It targets things. During normal playback, a signal corresponding to the tape running speed is compared with a first reference signal corresponding to the tape running speed during playback, and the tape is run at a constant speed, and the rotational speed of the drum is adjusted accordingly. This signal is compared with a second reference signal corresponding to the drum rotation speed during reproduction, and the drum is rotated at a constant speed.

In addition, when high-speed tape playback is required, the tape running speed is controlled by comparing a signal corresponding to the drum rotation speed with a third reference signal corresponding to the drum rotation speed during high-speed playback. At the same time, the rotational speed of the drum is controlled by comparing a signal corresponding to the reproduction data rate of the signal obtained from the head with a fourth reference signal corresponding to the reproduction data rate during high-speed reproduction. This is what I did.

(Function) According to the above configuration, when high-speed tape playback is requested, the tape is run at high speed in conjunction with the control to rotate the drum at high speed, so the tape running speed is detected. The tape running speed can be maintained at a desired constant value during high-speed playback without causing any problems, and the structure is simple, suitable for downsizing, and economically advantageous.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In FIG. 1, the same parts as in FIG. 4 are indicated with the same symbols. That is, the reel stand 12.
The FG pattern and FG pattern detection units 22 and 23 provided in the drum 1B and the tape speed detector 24 are deleted, and the FG double signal output from the FG pattern detection unit 19 of the motor 18 and the FG pattern detection unit 28 of the drum 1B are replaced. The FG multiplied signal outputted from the motor servo circuit 26 is selectively supplied to the motor servo circuit 26 by a changeover switch 25.

Furthermore, when high-speed tape playback is requested, the motor servo circuit 2B receives a drum motor high-speed rotation speed that specifies the rotation speed of the drum 16 during high-speed playback from a microcomputer that controls the operation of the digital audio recorder. A specified signal is supplied.

Furthermore, the reproduced signal output from the equalizer circuit 30 is supplied to a reproduced signal identification circuit 35. The reproduced signal identification circuit 35 identifies the presence or absence of a reproduced signal, and is at "H" level when the reproduced signal is present, and "L" when it is absent.
“It outputs a level identification signal.

In addition, the drum servo circuit 33 is configured to
The data output from the playback data rate detector 31
If the frequency of the rate detection signal deviates greatly from the frequency of the reproduced data rate designation signal supplied from the microcomputer mentioned above, the signal is "L" level, and if it is close to the frequency of the reproduced data rate designation signal, the signal is "H". This outputs a level drum servo lock signal.

The operation of the above configuration will be described below. First, during normal playback, the selector switch 25 is switched to the FG pattern detection unit 19 side, and an FG double signal corresponding to the rotational speed of the motor I8 is supplied to the motor servo circuit 26. Then, the motor servo circuit 26 controls the rotational speed of the motor 18 so that the FG double signal frequency matches the frequency of the motor rotational speed designation signal, so that the tape is run at a constant speed corresponding to normal playback. It is something that is controlled.

On the other hand, the changeover switch 32 is switched to the FG pattern detection section 28 side, and the FG multiplied signal corresponding to the rotational speed of the drum 16 is supplied to the drum servo circuit section.

Then, the drum servo circuit 33 controls the rotational speed of the drum motor 27 so that the FG double signal frequency matches the frequency of the drum motor rotational speed designation signal, and the drum 6 rotates at a constant speed corresponding to normal playback. It is controlled so that the

Next, the operation during high-speed reproduction will be explained with reference to FIG. In addition, FIG. 2(a) shows the relationship between the rotational speed of the drum 1B, the tape speed multiplier, and time, and the solid line in the figure shows the rotational speed of the drum 16, and the dotted line shows the tape speed multiplier. There is. Further, FIG. 2(b) shows the relationship between the reproduction data rate and time, and FIG. 2(c) shows the identification signal output from the reproduction signal identification circuit 35.
d) shows a drum servo lock signal output from the drum servo circuit 33.

That is, before time t1 when high-speed reproduction is required, all operations of the motor 18, drum motor 27, etc. are stopped, and the changeover switches 25 and 32 are respectively switched to the FG pattern detection section 19 and 2111 side. .

When high-speed playback is requested at time t1, first, a drum motor rotation speed designation signal is sent from the microcomputer to the drum servo circuit to specify that the drum 16 be rotated at 2000r, p, m, which corresponds to normal playback. 3
At the same time, a motor rotation speed designation signal is generated to the motor servo circuit 26, which designates that the tape be run at a speed corresponding to normal playback.

Therefore, the drum servo circuit 33 rotates the drum motor 27 so that the FG multiplied signal frequency output from the FG pattern detection section 28 matches the frequency of the drum motor rotation speed designation signal.

Further, the motor servo circuit 2B includes the FG pattern detection section 1
The motor 18 is driven to rotate so that the frequency of the FC signal output from the motor 9 matches the frequency of the motor rotation speed designation signal.

Then, at time t2, the rotational speed of the drum 16 reaches 200°r.
, p, m, and the tape begins to run at the normal playback speed, the drum servo lock signal goes to the "H" level, and stable tape playback is performed as in the normal playback state.

In such a playback state, when the playback signal identification circuit 35 generates an "H" level identification signal corresponding to the presence of a playback signal, the selector switch 25 switches the F of the drum 16 at time t3.
At the same time, the changeover switch 32 is switched to the reproduction data rate detector 31 side. Note that when the reproduction signal identification circuit 35 generates an "L" level identification signal corresponding to the absence of the reproduction signal, the identification signal remains "H" until the reproduction signal is obtained.
Normal tape playback operation continues until the level is reached.

Then, at time t3, when the changeover switches 25 and 32 are switched to the FG pattern detection unit 28 side and the playback data rate detector 3 side, the microcomputer commands the drum 16 to rotate at 3000r, p, m. A designated drum motor high rotational speed designation signal is generated to the motor servo circuit 2B, and a reproduction data rate designation signal that designates the reproduction data rate during normal reproduction is generated to the drum servo circuit 33.

Here, the rotational speed of the drum 16 of 3000r, p, a+ mentioned above is such that when the tape is run at a high speed 200 times the normal playback speed, the data rate of the obtained playback signal is the same as that during normal playback. Values that can be the same.

Therefore, the motor servo circuit 26 detects the rotational speed of the drum 16 (currently 20
The FG multiplied signal frequency corresponding to 0Or, p, IIl,) is compared with the frequency of the drum motor high speed rotation speed designation signal that specifies that the drum 16 be rotated at 3000 r, p, m, and the FG pattern is detected. In order to match the frequency of the FG double signal outputted from section 28 with the frequency of the drum motor high speed rotation speed designation signal, the rotation speed of motor I8 is increased and the tape is played at a high speed 200 times the normal playback speed. Control is performed to make the vehicle run.

In this way, when the tape running speed is gradually increased, the rotational speed of the drum 6 is around 2000r,p,++, so that the data rate detection signal output from the reproduction data rate detector 31 The frequency of will gradually increase. However, the drum servo circuit 33 gradually increases the rotational speed of the drum motor 27 so that the frequency of the data rate detection signal matches the frequency of the reproduction data rate designation signal.

Therefore, following the increase in tape running speed, the drum 1
At time t4, when the rotational speed of the drum 16 reaches 300Or,p,i, the tape running speed becomes 200 times the normal playback speed, and the playback data rate increases. High-speed reproduction is achieved by keeping the frequency close to the value (9,408 MHz) during normal reproduction. From then on, the motor servo circuit 2
B and drum servo circuit 33 are operated.

Next, assume that in the high-speed reproduction state as described above, at time t5, the reproduction signal is in no state, that is, the identification signal becomes "L" level. Then, the changeover switches 25.degree. 32 are respectively switched to the FG pattern detection sections 19 and 21i.

At this time, the motor servo circuit 26 is supplied with a motor rotation speed designation signal from the microcomputer that designates a tape running speed that is a predetermined amount slower than 200 times during normal playback. Therefore, the motor servo circuit 26
The rotational speed of the motor 18 is controlled so that the FG multiplied signal frequency output from the G pattern detection section 19 matches the frequency of the motor rotational speed designation signal, and the tape is rotated by a predetermined amount more than 200 times during normal playback. You will now be able to run stably at slow speeds.

Further, the drum servo circuit 33 is supplied with a drum motor rotation speed designation signal from the microcomputer that specifies that the drum 16 be rotated at a rotation speed of 300 Or, p, w. Therefore, the drum servo circuit 33 controls the rotational speed of the drum motor 27 so that the FG multiplied signal frequency output from the FC pattern detection section 28 matches the frequency of the drum monitor rotational speed designation signal, and The rotational speed is maintained at 3000r,p,m.

In this state, suppose that the reproduction signal is present again at time t6, that is, the identification signal becomes "H# level." Then,
The selector switch 32 is switched to the playback data rate detector 31 side, and the drum servo circuit 33 changes the frequency of the data rate detection signal output from the playback data rate detector 31 to the playback data rate during normal playback. The rotational speed of the drum unit 6 is set to 300 Or, p, 11 . The drum motor 27 is controlled to lower the drum motor 27 from below.

At this time, since the data rate of the reproduced signal deviates significantly from the reproduced data rate during normal reproduction, the drum servo lock signal goes to the "L" level.

Then, the rotational speed of the drum 16 is lowered, and at time t7, the frequency of the data rate detection signal output from the reproduction data rate detector 31 becomes the reproduction data rate that specifies the reproduction data rate during normal reproduction. When the frequency substantially matches the designated signal, the drum servo lock signal becomes "H2 level" and the changeover switch 25 is switched to the FG pattern detection section 28 side of the drum 16.

Then, the drum 1B is connected to the motor servo circuit 26 by 300 mm.
Since the drum motor high speed rotation speed designation signal designating rotation at 0r, p, a+ is supplied, at time t3
Similarly to the explanation above, if the tape running speed is 200 during normal playback,
times, the rotational speed of the drum 16 is 300 Or, p, 1. A high-speed playback state is realized.

Therefore, according to the configuration of the above embodiment, the reel stand 12. FG pattern and FC pattern detection section 2 in 13
2.23 etc. or complicated calculation processing of the tape speed, etc., the tape running speed and the rotational speed of the drum 16 can be stably maintained at a desired constant value during high-speed playback. It is simple, suitable for miniaturization, and can be economically advantageous.

FIG. 3 shows another embodiment of the invention.

In this embodiment, the present invention is applied to a type of digital audio tape recorder in which the reel stands 12 and 13 are rotated by independent glue motors (in the figure, they overlap with the reel stands 12 and 13). 1. Parts having the same functions as those in FIG. 1 will be described with the same symbols.

That is, FG patterns (not shown) are formed along the periphery of the reel stands 12 and 13, and
Each reel stand 12.
The FG multiplied signal corresponding to the rotation speed of 13 can be obtained. And this FC pattern detection section 38.39
FG multiplied signals output from each, selector switch 40
The signal is selectively guided to the selector switch 25 by the switch 25. This changeover switch 40 is connected to both reel stands 12.
Among 13, reel stand 12 or 1 is on the tape winding side.
The FG multiplied signals output from the FG pattern detection sections 38 and 39 provided in the FG pattern detection section 3 are switched and selected so as to be guided to the changeover switch 25.

Further, the motor drive signal output from the motor servo circuit 26 is transferred to the reel motor 38 by a changeover switch 41.
．． 37 is selectively supplied. This changeover switch 41 is selected to guide a motor drive signal to the reel motor 38.37 of the reel stand 12 or 13 on the tape winding side of both reel stands 12.13.

Therefore, in a state where high-speed tape playback is requested, the rotational speed of the reel motor 38.37 of the reel stand 12 or I3 on the tape winding side of both reel stands 12.13 is controlled in the same manner as in the above embodiment. began to be applied,
Substantially the same effects as in the above embodiment can be obtained, except that the structure is increased in size due to the provision of the FC pattern and FG pattern detection sections 38, 39 on the reel stand 12, 13.

Here, the FC signal obtained from the FG pattern detection section 19 of the motor 18 is supplied to the capstan servo circuit 42. This capstan servo circuit 42 controls the rotational speed of the motor 18 so that the frequency of the FC signal matches the frequency of the capstan rotational speed designation signal output from the microcomputer.

It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As detailed above, according to the present invention, the tape running speed can be maintained at a desired constant value during high-speed playback without detecting the tape running speed, and the configuration is simple and compact. Therefore, it is possible to provide an extremely good tape playback device that is suitable for the industry and economically advantageous.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing one embodiment of a tape playback device according to the present invention, FIG. 2 is a timing diagram for explaining the operation of the same embodiment, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is a block diagram showing a conventional tape playback device; FIG. 5 is a diagram illustrating changes in the head trajectory relative to the track depending on the tape running speed;
FIGS. 6 and 7 are diagrams for explaining the data format of one track, respectively. 11... Main chassis, 12.13... Reel stand, 14, 15... Head, 16... Drum, 17
...Capstan, 18...Motor, 19...F
G pattern detection unit, 20...Pulley, 2nd gear...Gear part, 22.23...FG pattern detection unit, 24...
Tape speed detector, 25... Selector switch, 26...
・Motor servo circuit, 27...Drum motor, 28・
...FG pattern detection section, 29...head amplifier, 3
0... Equalizer circuit, 31... Playback data rate detector, 32... Changeover switch, 33... Drum servo circuit, 34... Tape, 35... Playback signal identification circuit, 38. 37... Reel motor, 38.39.
... FC pattern detection section, 40.41... Changeover switch, 42... Capstan servo circuit. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A tape playback device that performs a helical scan by bringing a tape into contact with the peripheral surface of a drum having a head, rotating the drum and running the tape, comprising: a signal corresponding to the running speed of the tape; , first servo means for running the tape at a constant speed by comparing a first reference signal corresponding to a tape running speed during playback; a second servo means for rotating the drum at a constant speed by comparing it with a second reference signal corresponding to the rotational speed; a first control means for controlling the running speed of the tape by comparing the signal with a third reference signal corresponding to a drum rotation speed during high-speed playback; and in a state where high-speed playback of the tape is requested; , a second signal that controls the rotational speed of the drum by comparing a signal corresponding to the reproduction data rate of the signal obtained from the head with a fourth reference signal corresponding to the reproduction data rate during high-speed reproduction; 1. A tape playback device comprising: control means.