SU780029A1 - Magnetic recording-reproducing apparatus - Google Patents

Description

(54) DEVICE FOR MAGNETIC RECORDING

one

The invention relates to the field of instrumentation, in particular to the technique of magnetic recording.

A known magnetic modulation reproduction magnetic head with mechanical modulation of magnetic flux is based on a periodic mechanical change in the magnetic resistance of the core {l.

Such a magnetic head contains a core with a working and additional gaps and a winding and a ferromagnetic wedge dispersed in an additional gap mounted on the end of a vibrator made, for example, in the form of a piezo-ceramic bimorph element.

The disadvantages of this head are design complexity (presence of windings), low sensitivity, especially in the high frequency range.

It is also known a device for magnetic recording and playback, which contains a magnetic head, consisting of a core with a working and additional gaps, a piezo-converter with input electrodes of 1m connected to a generator AND PLAYBACK

ultrasonic frequency and with the output 7 electrode 2.

Such devices are not sufficiently large sensitivity.

5 The aim of the invention is to increase the sensitivity of the device. Achieving the goal

. - The device is equipped with an amplitude detector, 10 and the output electrode is made of ferromagnetic material and is attached to the end of the piezoelectric transducer facing the additional gap of the core, while the output

15, the electrode is coupled to an amplitude detector, and the piezotransducer is made in the form of a plate piezoelectric voltage transformer.

20 The drawing shows the irincipial scheme of the described device.

A piezo transducer 3, made in the form of a plate-shaped piezoelectric voltage transformer, is installed between the semi-cores 1 and 2, electrically connected with the ultrasonic generator 4 and the amplitude detector 5. The input electrodes b, 7 and the output electrodes 8 are applied to the piezoelectric transducer.

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A main working gap 9 and an additional gap 10 are formed between the half-cores.

When generator 4 is turned on to the input electrodes 6.7 of a piezoelectric plate voltage transformer 3, it converts electrical oscillations into mechanical (reverse piezoelectric effect), which in output electrodes 8.9 are again converted into electrical oscillations (direct piezoelectric effect) with more high voltage. Detector 5 performs detection, removingvioro from electrodes b, 7 voltage.

Simultaneously with the inclusion of the generator 4 in the half-cores 1.2 in the mode 2, a variable magnetic flux arises which, by means of the ferromagnetic output electrode 8, influences the operation of the plate piezoelectric voltage transformer 3, changing its load. Thus, the output voltage of the plate piezoelectric transformer 3, which is provided at the output of amplitude detector 5 as a useful reproducible signal.

Due to the fact that piezoelectric voltage transformers have transformation ratios over ioOO and are very

sensitive to changes in load, it is possible to obtain useful signals of large amplitude for reproducible information.

Claims (2)

1.Efimov E.G. Magnetic heads, Energy, m., 1976, p. 79, rice, b2a, 2. USSR author's certificate No. 621007, cl. G 11 B 5/00, 07.21.78.