SU1218420A1 - Device for magnetic recording of analog signals - Google Patents

Abstract

The invention relates to a magnetic recording technique and permits to expand the recording frequency range by dynamically adjusting the bias current. From this output of the recording amplifier, 1 part of the signal of the recorded operating frequency passes through the capacitor 4 to the gate of transistor 7, which controls the degree of modulation of operating frequency signals by high frequency biasing currents, which ensures that when resistors 5 and 8 are resisted, the range of recorded operating frequencies is extended to 18 kHz when using household tape recorders with a ferrite universal head. 1 nl 4J-L r22 :: rJ w (L o 00 1C

Description

one

This invention relates to a magnetic recording technique and can be used in household magnetic recording equipment.

The purpose of the invention is to expand the range of recorded frequencies by dynamically adjusting the bias current.

The drawing shows a schematic diagram of the device.

The device contains serially connected input bus, recording amplifier 1, notch filter 2 and recording head 3. The output of recording amplifier I is connected via a capacitor 4 and a variable resistor 5 with a negative potential bus 6. The middle terminal of the resistor 5 is connected to the gate of the field-effect transistor 7, the source and drain of which are connected respectively via an additional variable resistor 8 to the output of the erase and biasing generator 9 and directly to the output of the notch filter 2. The generator 9 inputs are connected to negative and positive buses 6 and 10 potentials, respectively, the first of which is connected to another output of the recording head 3. The field-effect transistor can be of the type KP UZL and the values of the capacitor 4 and resistor 5 are respectively about 680 pF and 1 MW.

The device works as follows.

From the output of the recording amplifier 1, a portion of the signal of the recorded operating frequency passes through the capacitor 4 to the gate of transistor 7, which controls the degree of modulation of the operating frequency signals by high currents.

low frequency bias, which ensures that with the right choice of resistors resistors 5 and 8, the expansion of the range recorded

working frequencies, in particular, up to 18 kHz when using household tape recorders of the Ш difficulty group with a ferrite universal head, i.e. a 3–4 dB increase in the S / N ratio.

Claims (1)

Invention Formula I .. A magnetic recorder of analog signals, containing a recording amplifier connected by an input to an input bus, and by a Vysode, to a high-pass filter input, an erase and biasing generator connected by inputs to the power buses, the left transistor, the notch filter and the recording head, which is so that, in order to expand the range of recorded frequencies by dynamically adjusting the bias current, the high-pass filter is made in the form of a series-connected capacitor and a variable resistor, the other and middle of which are connected respectively to the bus supply the negative potential and to the gate of the field-effect transistor connected by a source through another variable resistor additionally inputted with an erase and biasing generator, a drain to one output of the recording head and a notch filter to the output of the recording amplifier, the other end of the recording head is connected to the negative potential power bus.