JPH0132166Y2 - - 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 it has the disadvantage that 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 a take-out element and a regeneration coil are wound, and this core consists of two core halves on the left and right that are abutted against each other, one core half being integrally formed and the other core half being abutted against each other. It is characterized in that it consists of divided core elements divided in the width direction of the recording track, and that the difference signal extraction element consists of a magneto-electric detection element arranged between these divided core elements.

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 head structure. Since the difference signal is directly taken out from the magneto-electric detection element disposed between the split core elements of the core half, a differential amplifier is not required in the head azimuth adjustment device, which simplifies the device.

(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 respective recording tracks L and R of the recorded magnetic tape 1, and each head part 10LA and 10RA has a core and a reproducing coil wound around each core. It consists of. Head part 10LA for left channel
As shown in FIGS. 2A and 2B, the difference signal between the track division signals obtained by dividing and reproducing the recorded signal recorded on the left recording track L of the magnetic tape 1 in the width direction of this recording track is expressed as It consists of an element 24 for directly obtaining a difference signal and a core 11 in which the element 24 for taking out a difference signal is arranged. This core 11 consists of two core halves 1 on the left and right that are abutted against each other.
1A and 11B, one core half 11A is integrally formed and a reproducing coil 13 is wound around this core half 11A, and the other core half 11B is divided in the width direction of the recording track L as shown in the figure. It consists of two split core elements 11a and 11b joined with a non-magnetic spacer in between, and a reproducing coil 13' is wound across these two split core elements 11a and 11b, and a difference signal extraction element is formed. 24 is 2
It consists of a magneto-electric detection element such as a magnetoresistive element or a Hall effect element arranged between two divided core elements 11a and 11b. Incidentally, in FIG. 2, reference numeral 12 indicates a regeneration gap.

FIG. 3 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 element 24 is connected to the phase detector 18 via a regenerative amplifier circuit 14'L. The phase detector 18 detects the phase of the difference signal extracted from the difference signal extraction element 24 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 angle α, the fourth
By waveforms having phase relationships as shown in FIGS. A and B, it can be expressed as Sa=Asin(ωt+α/2) and Sb=Asin(ωt−α/2), respectively. 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 Figure 4C, and Sc = 2Acos α/2・sinωt. expressed. On the other hand, the difference signal Sd obtained from the difference signal extraction element 24 has a waveform delayed in phase by 90 degrees with respect to the audio reproduction signal Sc, as shown in FIG. 4D, and is expressed by Sd=2Asinα/2·cosωt. Conversely, when the azimuth of the playback head 10 is tilted counterclockwise relative 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 Figure 4, and Sd' = -. The phase differs by 180 degrees from the difference signal Sd expressed by 2Asinα/2·cosωt. Note that when the azimuths of both heads match, the difference signal Sd or Sd' is 0. The phase detector 18 detects, for example, an audio reproduction signal.
The polarity of the difference signal is determined using the zero cross points from "low" to "high" of Sc. If the difference signal is "-" at this zero cross point, the difference signal corresponds to the clockwise tilt of the playback head. Sd, and when it is "+", it is determined that it is a difference signal Sd' corresponding to the counterclockwise tilt of the reproducing 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, the difference signal becomes Sd=0, and when the difference signal is no longer detected, the rotation of the motor 21 is stopped. Ru. 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. Incidentally, when the difference signal Sd' is detected, the reproducing head 10 is tilted in the opposite direction to that described above, so that its azimuth matches that of the recording head. Also, instead of the control using the difference signal described above, the difference signal
It is also possible to use Sd and Sd' as signals whose pulse widths change in response to the phase difference between the virtual reproduction signals Sa and Sb, and to control the motor 21 based on this difference signal.

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 half of the core corresponds to the full width of the recording track, and only the other half of the core is divided in the width direction, so the number of coils is reduced. Also, since the difference signal extraction element is placed between these split core elements, the structure of the head is simplified, and since the difference signal is directly taken out from this magneto-electric detection element, a differential amplifier can be used in the head azimuth adjustment device. This eliminates the need for an automatic azimuth adjustment between the recording head and the playback head, which simplifies the device and has the practical benefit of allowing economical automatic azimuth adjustment between the recording head and the playback head.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an example of a magnetic head according to the present invention, FIGS.
Figure 4 is a system diagram of a device that uses the magnetic head of the present invention to adjust the position of the magnetic (reproducing) head.
The figure is a waveform diagram of signals at various parts shown in the apparatus of FIG. 3. 1...recorded magnetic tape, 10...magnetic head, 10LA, 10RA...head part, 11...
... Core, 11A, 11B ... Core half, 11a,
11b...Split core element, 12...Gap, 1
3, 13'... Reproduction coil, 18... Phase detector,
21...Motor for adjusting playback head azimuth, 2
4...Difference signal extraction element, Sa, Sb...Virtual track division signal, Sd...Difference signal.

Claims (1)

[Scope of utility model registration request] A difference signal extraction element for obtaining a difference signal between track division signals obtained by dividing and reproducing recording signals recorded on the same recording track of a magnetic tape in the width direction of the recording track, and a core around which a reproduction coil is wound. The core consists of two left and right core halves that are abutted against each other, one core half being integrally formed and the other core half being divided in the width direction of the recording track. 1. A magnetic head comprising a core element, wherein the difference signal extraction element comprises a magneto-electric detection element disposed between the split core elements.