JPS63244403A - Recording compensation circuit - Google Patents

Abstract

PURPOSE:To easily compensate the recording characteristic by utilizing the resonance of the output side of a rotary transformer in using a rotary magnetic head to apply recording and connecting a resistor. CONSTITUTION:A recording current is supplied to the rotary magnetic head 3 through a rotary transformer 2 and the resonance circuit 4 is constituted by an inductance of the rotary transformer 2 and the rotary magnetic head 3 and the line capacitance of the rotary transformer 2 and a harness. Then a resistor is connected to the resonance circuit 4 to obtain a required recording band width. Thus, the frequency characteristic of the recording circuit has a peak at a frequency Hz0 and the level of peak is set optionally by a resistor R1, then proper recording is attained. In providing the peak at the frequency Hz0, a recording signal has an overshoot and an excellent signal is reproduced more than the case with recording a simple rectangular wave.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a compensation circuit for recording characteristics.

[Summary of the invention]

In the case of recording using a rotating magnetic head, the present invention compensates for recording characteristics by utilizing resonance on the output side of a rotary transformer and by connecting a resistor.

[Conventional technology]

In a digital VTR, in order to make the current waveform of the recording signal supplied to the rotating magnetic head equal to the waveform of the input signal (digital signal) to the recording circuit, the recording circuit needs to have a transmission speed that is approximately 3 to 5 times the transmission speed of the recording signal. bandwidth is required.

[Problem that the invention seeks to solve]

However, in digital VTRs, the transmission speed of recording signals reaches approximately 50 to 100 Mbaud, so
The bandwidth of the recording circuit can only be approximately 1 to 2 times as large as the recording signal, resulting in insufficient bandwidth.

Therefore, if the input signal (voltage) Vl of the recording circuit has a waveform and frequency spectrum as shown in Figure 5A and H, the frequency characteristics of the recording circuit will be as shown in Figure C, so in reality Recording signal (current) supplied to the head
The waveform and frequency spectrum of No. 12 have degraded high frequencies, as shown in E in the figure.

With such a recording signal, it becomes difficult to realize reliable recording and reproduction, resulting in problems such as an increase in error rate.

This invention attempts to solve these problems.

[Means for solving problems]

Therefore, in this invention, the recording current is supplied to the rotating magnetic head through the rotary transformer, and
The inductance of the rotary transformer and rotating magnetic head, and the line capacitance of the rotary transformer and harness constitute a resonant circuit, and a resistor is connected to this resonant circuit to obtain the necessary recording bandwidth. It is something.

[Effect] The high frequency characteristics of the recording signal waveform are compensated.

〔Example〕

In Fig. 1, (1) is a recording amplifier, (2) is a rotary transformer, and (3) is a rotating magnetic head exclusively for recording. supplied to

In this case, the line capacitance C1 caused by the cable connecting the amplifier (1) and the transformer (2), the input coil of the transformer (2), the output coil of the transformer (2), the transformer (2), and the head ( A resonant circuit (4) whose resonance frequency is higher than the cutoff frequency of the amplifier (11) is created by the line capacitance C2 of the printed circuit board connecting the amplifier (3) and the inductance of the transformer (2) and head (3). Configure.

Also, at this time, a resistor R1 is connected in parallel with the head (3), and the Q-dump of the resonant circuit (4) is performed by this resistor (3).

Note that the resonant frequency fo of the resonant circuit (4) is mainly determined by the capacitors MCs, C2, and the inductances of the transformer (23 and head (3)), so these capacitors C1,
By selecting C2 and the configuration of the member providing inductance, such as the length of the cable and the number of turns of the coil, the resonant frequency fo can be set to a required value. Also, if necessary, you can connect a capacitor.

According to this configuration, the frequency characteristics of this recording circuit have a peak at the frequency ro, as shown in FIG. 2, and the magnitude of this peak can be arbitrarily set by the resistor R1.

Therefore, a necessary recording band can be secured for the recording signal, and proper recording can be performed. Further, by giving a peak to the frequency fo, the recorded signal has an overshoot as shown in FIG. 3, and a better signal can be reproduced than when a simple rectangular wave is recorded.

In addition, when driving the head (3) with voltage, for example, as shown in FIG. C3 and the stray capacitance C4 constitute a resonant circuit (5), and a Q-dump resistor R2 may be connected in parallel to the coil L1.

That is, by doing this, the voltage transfer characteristic becomes a differential characteristic, so that the recording current supplied to the head (3) has a flat frequency characteristic, and the resonant circuit (5) provides supplementary high-frequency compensation. It will be done. Therefore, the resonant circuit (4
), better recording characteristics can be obtained.

Furthermore, in the above description, a recording amplifier (output stage) may be provided between the transformer (2) and the head (3).

〔Effect of the invention〕

According to this invention, the frequency characteristic of this recording circuit is
As shown in the figure, there is a peak at the frequency fo, and the magnitude of this peak can be arbitrarily set by the resistor R1, so that a necessary recording band can be secured for the recording signal, and proper recording can be performed.

Further, by giving a peak to the frequency fo, the recorded signal has an overshoot as shown in FIG. 3, and a better signal can be reproduced than when a simple rectangular wave is recorded.

[Brief explanation of drawings]

FIG. 1 is a connection diagram of an example of the present invention, and FIGS. 2 to 5 are diagrams for explaining the same. (1) is a recording amplifier, (2) is a rotary transformer, (
3) is a rotating magnetic head, and (4) is a resonant circuit.

Claims (1)

[Claims] An apparatus for recording information signals using a rotating magnetic head, in which a recording current for the information signal is supplied to the rotating magnetic head through a rotary transformer, and the rotary transformer, the rotating magnetic head, etc. A resonant circuit is constituted by an inductance and a line capacitance such as the rotary transformer and a harness, and the resonance of this resonant circuit performs high-frequency compensation of the recording current supplied to the rotary magnetic head. A recording compensation circuit in which a resistor is connected in parallel to compensate for the magnitude of the above-mentioned high frequency compensation.