JPH0127131Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an improvement of a magnetic head suitable for adjusting azimuth using recording signals such as music recorded on the same recording track of a magnetic tape. It is.

(Prior art) For example, when playing back a commercially available recorded magnetic tape such as a music tape, the azimuth of the playback head must be adjusted to match the azimuth of the recording head used when recording the recorded magnetic tape. If possible, optimal playback characteristics can be obtained. Furthermore, in a tape recorder equipped with independent recording and playback heads, the azimuths of the recording head and playback head must match, so that music, etc. can be recorded with the recording head and the recorded signal can be played back simultaneously with the playback head. is required. Therefore, it would be extremely effective if the azimuth of the magnetic head could be detected using recorded signals such as music recorded on magnetic tape.

Recently, a recording signal recorded on the same recording track is divided in the width direction of this recording track, the two divided signals are played back, and the optimum azimuth for this recording signal is determined based on the difference signal between the track divided signals. A device for adjusting the reproduction head has been proposed (see Japanese Patent Laid-Open No. 14597/1983). According to this device,
The azimuth relationship between the recording head used to record the recording signal and the reproduction head is detected, and the reproduction head is adjusted to match the azimuth of the recording head used when recording the recording signal, so that optimal reproduction is performed. However, in this proposed device, the magnetic head has two divided core elements divided into upper and lower parts, each of which is wound with a divided coil that obtains two divided signals. The azimuth adjusting device requires a differential amplifier to obtain a difference signal between the divided signals, so the structure of the device is complicated.

(Purpose of the invention) The purpose of the invention is to be able to directly obtain the difference signal between two divided signals with a simple structure, and to economically perform automatic azimuth adjustment between the recording head and the playback head with a simple device. The object of the present invention is to provide a magnetic head that can

(Structure of the invention) The magnetic head of the invention divides and reproduces recording signals recorded on the same recording track of a magnetic tape in the width direction of this recording track, and obtains a difference signal between the track division signals. It consists of a core around which the take-out coil, the difference signal take-out coil, and the reproducing coil are wound, and this core consists of two left and right core halves that are abutted against each other, and one core half is formed integrally. and the other core half has a divided core element divided in the width direction of the recording track and an auxiliary core element spanning between the divided core elements,
The difference signal extraction coil is characterized in that it is wound around this auxiliary core element.

With this configuration, one core half corresponds to the entire width of the recording track, and only the other core half is divided in the width direction, reducing the number of coils and simplifying the structure of the head. Since the difference signal extraction coil is wrapped around the auxiliary core element that straddles between the split core elements in the core half, the difference signal can be taken out directly, eliminating the need for a differential amplifier in the head azimuth adjustment device and simplifying the equipment. becomes.

(Embodiment) An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a magnetic head 10 in the form of a playback head according to the present invention. It consists of head parts 10LA and 10RA for the left and right channels corresponding to the recording tracks L and R of the recorded magnetic tape 1, and each head part 10LA and 10RA has a core and a coil wound around each core. It consists of. The head part 10LA for the left channel is
As shown in FIG. 2, the recording signal recorded on the left recording track L of the magnetic tape 1 is divided and played back in the width direction of this recording track, and the difference signal of the track division signals is directly obtained. It consists of a core 11 around which a coil 13ab, this difference signal extraction coil (differential coil) 13ab, and a reproducing coil are wound. This core 11 consists of two core halves 11A and 11B on the left and right that are abutted against each other, one core half 11A is integrally formed, a regeneration coil 13 is wound around this core half 11A, and the other core half 11A is formed integrally. The core half portion 11B is divided into two divided core elements 11a and 11b which are divided in the width direction of the recording track L and joined together with a non-magnetic layer (not shown) in between, and an auxiliary core which straddles between these divided core elements 11a and 11b. element 11e, and the reproducing coil 1 straddles these two divided core elements 11a and 11b.
3' is wound around this auxiliary core element 11e, and the difference signal take-out coil 13ab is wound around this auxiliary core element 11e. In FIG. 2, reference numeral 12 indicates a regeneration gap.

FIG. 4 shows an apparatus for adjusting the azimuth of a magnetic head using the magnetic head 10 of the present invention. The reproduction coils 13, 13' are connected in series, and the reproduction signal taken out from these reproduction coils 13, 13' is as follows.
The signal is input to the reproduction amplifier circuit 14L, and the output of the reproduction amplifier circuit 14L is directly output from the audio output terminal 15L as the audio reproduction signal Sc of the left channel. On the other hand, the difference signal extraction coil 13ab is connected to the phase detector 18 via a regenerative amplifier circuit 14'L. Phase detector 18
detects the phase of the difference signal extracted from the difference signal extraction coil 13ab with reference to the zero cross point of the audio reproduction signal Sc. The output of the phase detector 18 is input to the motor drive circuit 20 as a control signal for controlling an azimuth adjustment motor 21 that drives an adjustment member (not shown) such as an azimuth adjustment screw that changes the azimuth of the reproduction head 10. .

Although not shown, the playback signal taken out from the right channel head portion 10RA is output as a right channel audio playback signal from the audio output terminal via a playback amplifier circuit.

Next, the state of adjusting the azimuth using the magnetic head 10 of the present invention will be described with reference to FIG.
The virtual playback signals Sa and Sb that are divided and extracted by signals 1a and 11b are generated so that the azimuth of the playback head 10 is clockwise when viewed from the front of the playback head 10 with respect to the azimuth of the recording head used when recording the recording signal. If the phase angle is tilted by an angle α, the fifth
Sa=Asin(ωt+α/2) and Sb=Asin(ωt
−α/2). Therefore, the composite signal extracted as the audio reproduction signal Sc has a waveform whose phase is delayed or advanced by α/2 relative to Sa and Sb, respectively, as shown in FIG.
It is expressed as =2Acosα/2・sinωt. On the other hand, the difference signal Sd obtained from the difference signal extraction coil 13ab has a waveform delayed by 90 degrees in phase with respect to the audio reproduction signal Sc, as shown in FIG. 5D, and Sd=2Asinα/
It is expressed as 2・cosωt. Conversely, when the azimuth of the playback head 10 is tilted counterclockwise with respect to the azimuth of the recording head when viewed from the front of the playback head 10, the difference signal Sd' becomes as shown by the dotted line in FIG.
The difference signal Sd is expressed as Sd′=−2Asinα/2・cosωt
The phase is 180 degrees different from that of Note that when the azimuths of both heads match, the difference signal Sd or Sd' is 0. The phase detector 18 determines the polarity of the difference signal using, for example, the zero-crossing points from "low" to "high" of the audio reproduction signal Sc. When the difference signal is "-" at this zero-crossing point, the reproducing head It is determined that the difference signal Sd corresponds to a clockwise tilt, and when it is "+", it is a difference signal Sd' corresponding to a counterclockwise tilt of the reproduction head 10. If the difference signal Sd is detected, the motor drive circuit 20 is controlled to rotate the motor 21 in a direction that tilts the reproduction head 10 counterclockwise. In this way, the azimuth of the playback head 10 relative to the recording head is adjusted so that the azimuths of the playback head 10 and the recording head match, and the difference signal becomes Sd=0.
When the difference signal is no longer detected, the rotation of the motor 21 is stopped. As a result, the audio reproduction signals of the left and right channels are respectively output from the audio output terminals with the azimuths of the reproduction head 10 and the recording head matching. Furthermore, the difference signal
If Sd' is detected, the playback head 10 is tilted in the opposite direction to that described above so that its azimuth matches that of the recording head. In addition, instead of the control using the difference signal described above, the difference signals Sd and Sd′ are used as the virtual reproduction signals Sa and Sb.
It is also possible to use a signal whose pulse width changes in response to the phase difference between the two, and to control the motor 21 based on this difference signal.

FIG. 3 shows a modification of the present invention, in which one core half 11B of the core 11 is divided into four divided core elements 11a, 11a', 11b, 1.
1b', and an auxiliary core element 11e is provided spanning between the inner two divided core elements 11a' and 11b of these four divided core elements, and around which a difference signal extraction coil 13ab is wound. . This modification is preferable because the difference signals Sd and Sd' can be reliably detected even if the height position of the head portion 10LA with respect to the recording track L of the magnetic tape 1 is slightly deviated.

Although the core for the left channel is divided in the above embodiment, it is needless to say that the core for the left channel is not limited to this.In addition, in the above embodiment, when playing back a commercially available recorded magnetic tape, the playback head 10 is divided into two parts. In the above description, the azimuth of either head may be adjusted to match the azimuth of the head in a tape recorder having independent recording and playback heads.

(Effects of the invention) According to the invention, as described above, one core half corresponds to the entire width of the recording track, and only the other core half is divided in the width direction, so the number of coils is reduced. This simplifies the structure of the head, and since the difference signal extraction coil is wound around the auxiliary core element that spans between the split core elements of the other half of the core, the difference signal is directly taken out. This eliminates the need for a dynamic amplifier, simplifies the device, and has the practical benefit of allowing automatic azimuth adjustment between the recording head and the reproducing head to be carried out economically.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of a magnetic head according to the present invention, FIG. 2 is a perspective view of one head portion of the magnetic head of the present invention, and FIG. 3 is a perspective view of a modified example of the magnetic head of the present invention. FIG. 4 is a system diagram of an apparatus for adjusting the position of the magnetic (reproducing) head using the magnetic head of the present invention, and FIG. 5 is a waveform diagram of signals of various parts shown in the apparatus of FIG. 1... Recorded magnetic tape, 10... Magnetic playback head, 10LA, 10RA... Head part, 11
... Core, 11A, 11B ... Core half, 11
a, 11a', 11b, 11b'... split core element,
12... Gap, 13, 13'... Regeneration coil,
13ab...Difference signal extraction coil, 18...Phase detector, 21...Motor for adjusting reproduction head azimuth, Sa, Sb...Virtual track division signal, Sd...
...difference signal.

Claims (1)

[Claims for Utility Model Registration] (1) Difference signal extraction for obtaining a difference signal between track division signals obtained by dividing and reproducing recorded signals recorded on the same recording track of a magnetic tape in the width direction of said recording track. It consists of a core around which a coil, the difference signal extraction coil and the reproducing coil are wound, and the core consists of two left and right core halves that are abutted against each other, and one core half is integrally formed. , the other core half has a split core element divided in the width direction of the recording track and an auxiliary core element spanning between the split core elements, and the difference signal extraction coil is wound around the auxiliary core element. A magnetic head characterized by: (2) The other core half consists of four divided core elements divided in the width direction of the recording track, and the auxiliary core element straddles the inner two divided core elements of the divided core elements. A magnetic head according to claim 1 of the utility model registration claim.