JPH0320801B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cassette tape recorder, and more particularly to one in which digital signals are recorded and reproduced on and from a magnetic tape in a cassette using a rotating magnetic head.

Conventionally, fixed head type and rotary head type cassette tape recorders for recording and reproducing digital signals have been proposed.

However, the fixed head type, in which the head is inserted into the cassette, has a complicated structure because it requires a multi-track head with dozens to several dozen tracks and dedicated circuits for amplification, compensation, detection, etc. for each track. Along with this, it also had the disadvantage of high costs.

In addition, rotary head type devices that pull the tape out from the cassette require a tape pull-out mechanism, which has the disadvantage of complicating the structure.Especially when using a popular compact cassette, it is extremely difficult to pull out the tape without straining. It was hot.

The present invention eliminates such conventional drawbacks, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1a is a cross-sectional front view of the main part of the rotary head device 16 used in the tape recorder of the present invention, and FIG. 1b is a top view of the main part of the rotary head device 16 viewed from the inside of the cassette on the side that faces the tape. are shown respectively.
A cylindrical first electric conductor 4 to which one end of a winding 2 wound around a ring-shaped core 1 is connected, and a cylindrical second conductor 5 to which the other end of this winding 2 is connected. are integrally insulated from each other by an insulating member 6 interposed therebetween. The conductors 4 and 5 are rotatably supported by radial bearings 11 and 11 on a stator 9 disposed on a well-known head board (not shown) in a cassette tape recorder. 12 is belt 17
The magnetic tape 13 is rotated by a motor 18 via a rotation axis perpendicular to the running surface of the magnetic tape 13. Note that the center of this rotation axis is set to be located approximately at the center of the width of the magnetic tape 13.

A closing member 15 that forms a contact surface with the magnetic tape 13 is fitted into one open end of the conductor ₅ that is inserted through the opening 14 1 of the cassette 14 . A magnetic head 19 consisting of two is supported. The operating gap 3 of the magnetic head 19 is spaced apart from the center of rotation of the conductors 4, 5 by more than half the width of the tape, and is formed in a direction perpendicular to the direction of rotation of the conductors 4, 5. The inner diameter of the conductor 5 is selected such that the diameter of the closing member 15 is larger than the width of the magnetic tape 13, and the tape contacting surface of the closing member 15 is a curved surface with a radius of curvature sufficiently larger than the radius of the closing member 15. As a result, the magnetic tape 13 to which the required tension has been applied is brought into complete contact with the tape contacting surface of the closing member 15.

Further, 7 and 8 indicate contacts, respectively, which connect the winding 2 to a recording or reproducing circuit via conductors 4 and 5. Reference numerals 10 and 10 indicate tape guides provided on the stator 9, and are arranged on the upstream and downstream sides of the closing member 15.

FIG. 2 shows a recording track 31 formed when the tape recorder of the present invention records on the magnetic tape 13 running in the direction of the arrow shown in the figure. The rotation angle is set as the head active angle.

Next, the operation will be explained with reference to the circuit diagram of FIG. 3 and the time chart of FIG. 4 in addition to FIG.

When the recording mode is selected, the head substrate is moved from the retracted position to the forward position with respect to the oriented cassette 14 as is well known, and the rotary head device 16 is inserted into the cassette through the opening ₁₄₁ formed in the front surface of the cassette 14. , and its tape-contacting surface is brought into contact with the magnetic tape 13 being run with the required tension. The analog signal input to the input terminal 21 is converted into a continuous PCM signal having the required number of bits by the A/D converter 22 as shown in FIG.
After being modulated into a pulse train, it is input to the first buffer memory 23. Since the active period of the magnetic head 19 is approximately 90 degrees in its rotation angle, the buffer memory 23 records the pulse train P ₁ to _{P 10} within the time t ₁ corresponding to one rotation of the magnetic head 19 within the active period t ₂ . As shown in FIG. 4b, this pulse train _P1 to _P10 is preferably compressed and output. After this compressed output pulse train _p1 to _p10 is subjected to necessary processing such as digital modulation by the recording signal processing circuit 24, the movable contact ₂₅₁ of the changeover switch 25 is connected to one fixed contact _252. The data is thereby supplied to the magnetic head 19 and recorded on the magnetic tape 13.

Reproduction of the pulse signal recorded on the magnetic tape 13 is achieved by connecting the movable contact 25 ₁ of the changeover switch 25 to the other fixed contact 25 ₃ .
The reproduced signal from the magnetic head 19 is input to a reproduced signal processing circuit 26. This circuit 26 performs processing opposite to that of the recording signal processing circuit 24, and after performing code error correction, etc., the output pulse signal p ₁
~ _p10 is sent to the second buffer memory 27.
The buffer memory 27 expands the compressed reproduction signal into the original continuous pulse train P ₁ to _{P 10} and then sends this pulse signal to the D/A converter 28 , whereby a demodulated analog signal is taken out from the output terminal 29 . It will be done.

In such a tape recorder of the present invention, accurate tracking of recording tracks is possible without using a synchronizing signal or the like. Figure 5 shows magnetic tape 1
This shows a case in which track deviation occurs during playback due to elongation of tape No. 3, fluctuations in tape transport speed, or play in the running system (not shown).

The point 0 ₀ is the rotational center position of the magnetic head 19 during recording, and if, for example, the transport speed of the magnetic tape 13 becomes slow during reproduction, the rotational center position of the magnetic head 19 during reproduction will be the same as the tape traveling on the magnetic tape 13. Displaced in the direction and become the point 0 ₁ . As a result, the length of the track 31 with respect to the active angle of the magnetic head 19 is different during recording and during reproduction, and the length 1 ₂ of the track 31 during reproduction is 1 ₂ > 1 ₁ compared to the length 1 ₁ during recording. becomes. That is, during reproduction, the relative velocity with respect to the recording signal increases, and the period of the pulse trains p ₁ to p ₁₀ decreases. This state is shown in FIG. 4c.

Furthermore, when the transport speed of the tape 13 increases, the rotational center position of the magnetic head 19 is displaced in the direction opposite to the tape running direction, and becomes point ₀₂ . In this case, contrary to the above, the relative velocity with respect to the recording signal becomes small and the period of the pulse trains p ₁ to _{p 10} becomes large. This state is shown in FIG. 4d.

Furthermore, during playback, the center of rotation of the magnetic head 19 is located on the magnetic tape 13 in the width direction of the tape 13.
When the pulse train p 1 to p 10 is displaced in the direction B shown in the figure in the width direction and reaches point 0 ₃ , the pulse train p ₁ to _{p 10} is
Move in parallel. This state is shown in FIG. 4e.

Further, the pulse train p ₁ when the rotation center position of the magnetic head 19 is displaced in the direction C shown in the figure and becomes a point 0 ₄
~p ₁₀ is shown in Figure 4f.

Therefore, tracking control becomes possible by detecting variations in the reproduction pulse train p ₁ to _{p 10} during the active period of the magnetic head 19.

The present invention is not limited to the above embodiments, but
Of course, various embodiments may be used, such as extracting the output signal from the winding using a well-known rotary transformer or providing two magnetic heads.

As described above, according to the present invention, it is possible to record and reproduce digital signals using a rotary head using the same tape drive system as a conventional cassette tape recorder without pulling out the magnetic tape from the cassette. A cost-effective cassette tape recorder can be provided.

[Brief explanation of the drawing]

1A and 1B are diagrams for explaining the rotary head device of the cassette tape recorder of the present invention, FIG. 2 is a diagram for explaining the recording track in the cassette tape recorder of the present invention, FIGS. 3, 4, and 5. The figures respectively show a circuit diagram and a time chart for explaining the cassette tape recorder of the present invention. 3...gap, 13...magnetic tape, 14...
...Cassette, 16...Rotary head device, 18...
Motor, 19...magnetic head.

Claims (1)

[Scope of Claims] 1. A rotating member that can be inserted into an opening of a cassette that stores a magnetic tape and whose center of rotation is centered on the tape width; a tape contacting portion having a curved surface having a diameter larger than the tape width; and a tape contacting portion having a diameter larger than the tape width; A cassette tape recorder comprising: a magnetic head disposed in the tape contacting section for recording and reproducing data with a constant rotation locus in a plane parallel to the running surface of the magnetic tape.