JPS5914898Y2 - magnetic recording and playback device - Google Patents

Description

[Detailed explanation of the invention] In general, in a magnetic recording/playback device, if the playback frequency characteristics extend to high frequencies, the high-frequency noise of the magnetic tape will also be reproduced in a large amount at the same time, which may become harsh to the ears. be.

In particular, when a magnetic tape with a low recording level is reproduced, high-frequency noise often becomes larger than the level of the reproduced signal, which is extremely inconvenient.

This proposal eliminates the above-mentioned conventional drawbacks,
A capacitor is connected to the magnetic head, and the inductance of the magnetic head itself and the above capacitor form a low-pass P-wave filter, and this low-pass filter attenuates the high-frequency components of the output of the magnetic head. It is composed of

EMBODIMENT OF THE INVENTION Hereinafter, the magnetic recording and reproducing apparatus of this invention will be described with reference to the drawings of one embodiment.

In the figure, 1 is a magnetic head for recording and playback, 2 is a capacitor connected in parallel to the magnetic head 1, 3 is a transistor connected in series to capacitor 2, 4 is a resistor, and 5 is the base of transistor 3. and a reference voltage source 11, 6 is an amplifier circuit for recording and playback, 7 is a capacitor connected between the base and emitter of transistor 3, 8 is a diode, 9° and 10 are amplifier circuits 6 It is a resistor that divides the output appearing at the output terminal of the .

In the above embodiment, when the output reproduced by the magnetic head 1 is above a predetermined value, the output of the amplifier circuit 6 becomes a signal having a peak value above the predetermined value, so it is accumulated in the capacitor 7 through the diode 8. The electric charge generated increases, and this acts negatively on the voltage applied from the reference voltage source 11, so that eventually the base bias of the transistor 3 becomes close to a reverse bias, and the effect of the capacitor 2 becomes almost non-existent. .

However, if the output reproduced by the magnetic head 1 now becomes smaller than a predetermined value, the charge accumulated in the capacitor 7 through the diode 8 will become smaller, and in this connection, the transistor 3 will be biased in the forward direction. Become.

Therefore, in this case, a low-pass filter is constructed by the inductance of the magnetic head 1 and the capacitor 2, and the high-frequency components of the output reproduced by the magnetic head 1 are greatly attenuated. Almost no high frequency noise component of the magnetic tape appears at the output terminal of the amplifier circuit 6.

As described above, according to the present invention, the high-frequency noise component of the magnetic tape can be greatly attenuated when the output of the magnetic head is low, and there is almost no harshness even when playing back a magnetic tape with a low recording level. It is something.

According to this proposal, the low-pass filter that attenuates high-frequency noise is composed of the inductance of the magnetic head itself and a capacitor connected in parallel with it, so the overall configuration is extremely simple. It is extremely advantageous from a practical point of view, as the properties can be made relatively good.

[Brief explanation of drawings]

The figure is an electrical wiring diagram of a main part of an embodiment of the magnetic recording and reproducing apparatus of the present invention. 1...Magnetic head, 2...Capacitor, 3...Transistor, 4. 5. 9.10
...Resistor, 6...Amplification circuit, 7...
... Capacitor, 8... Diode, 11.
...Reference voltage source.

Claims (1)

[Scope of utility model registration request] a low-pass filter constituted by the inductance of the magnetic head itself and a capacitor provided separately; a detection means for detecting the reproduction output level of the magnetic head; and a detection means for detecting the reproduction output level of the magnetic head based on the output of the detection means. 1. A magnetic recording and reproducing apparatus comprising: a control section that increases the amount of attenuation of high-frequency components by the low-pass filter when the output level becomes equal to or lower than a predetermined level.