JPH08124103A - Recording amplifier circuit - Google Patents

Abstract

PURPOSE: To obtain a recording signal compensated in the low frequency cut-off characteristic of a rotary transformer with simple configuration by providing a means variably controlling a current flowing through amplification means based on the output result of a charging means. CONSTITUTION: A recording signal modulated by a digitized information signal is supplied to amplification means 2, 3, Q1, Q2, Vcc and a detection means 4. Then, a current generated in the secondary side of a pulse transformer 2 by a constant current supplied from Vcc is supplied to a rotary transformer 1 as the recording signal. The detection means 4 supplies the detection signal of the rising or the falling of the recording signal to a charging means 5, charges a current to a prescribed target value with the same time constant as the low frequency cut-off characteristic of the transformer 1 and amplifies it to a prescribed level to supply it to a control means 6. The means 6 varies the current flowing through the transformer 2 based on the output result of the charging means 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / amplifying circuit for effectively improving the characteristics of a rotary transformer having a cutoff characteristic in a low frequency region in a magnetic recording device.

[0002]

2. Description of the Related Art Conventionally, there is a magnetic recording apparatus for recording information signals such as digital signals at high density on a magnetic tape or the like using a rotary head. In such a magnetic recording device, a recording signal obtained by modulating a digital signal is amplified to a predetermined level by an amplifier circuit and supplied to a rotary head via a rotary transformer. The rotary head records the supplied recording signal on the magnetic tape.

Here, when digital signals having various data rates are recorded by the above-mentioned magnetic recording apparatus, since the digital signals having a low data rate are modulated into a recording signal having a low frequency, a low frequency region of the rotary transformer is obtained. There is a problem that the low frequency component of the recording signal is blocked due to the blocking characteristic in.

Even when the information signal having a low data rate is not modulated, when the information signal is recorded by using the modulation method having the frequency components up to DC,
I had a similar problem.

Therefore, for example, there is a method of using a modulation method for modulating an 8-bit pattern into a signal having a low frequency component of 10 or 14 bits. However, since the recording signal has redundancy, when the recording signal is recorded on the magnetic tape, the improvement of the recording density is limited.

In order to solve the above problems, a magnetic recording apparatus is provided with a rotary transformer and an amplifying circuit for amplifying the recording signal, which is provided with integrating means for compensating the low frequency of the recording signal (Japanese Patent Laid-Open No. 4-111202). ) Was proposed.

[0007]

However, in the above-mentioned magnetic recording device, the low-frequency component of the recording signal is integrated into the integrators 2, 1
After emphasizing with 1, this is a recording amplifier with good linearity 4, 14
In order to amplify the rotary transformer by amplifying with, the same performance as when recording an analog signal is required even if the signal to be recorded is a digital signal, so an amplifier with high speed and good linearity is required. Further, in this case, there is a problem that the power efficiency is lower than when signal control is performed by using switching operation of a transistor or the like. That is, there is a problem that it is an expensive, complicated, and high-power circuit.

In general, even a modulation method that does not include a direct current component includes a low frequency component. Therefore, when a recording signal obtained by this modulation method is recorded through a rotary transformer, the low value of the rotary transformer is used. There is a problem that the low frequency component of the recording signal is blocked due to the blocking characteristic in the frequency domain.

Therefore, it is desired to solve the above-mentioned problems and to introduce a recording / amplifying circuit having a simple structure.

[0010]

Therefore, the present invention provides the following constitution in order to solve the above-mentioned problems.

In a recording amplifier circuit used in a magnetic recording apparatus for recording a digital signal supplied to a rotary head via a rotary transformer on a magnetic tape, a predetermined current is supplied to the rotary transformer based on the recording signal. An amplifying means, a detecting means for detecting an edge of the recording signal, and a charging means having a characteristic opposite to a low frequency cutoff characteristic of the rotary transformer for charging an electric current to a target value based on a detection result of the detecting means. And a control means for variably controlling the value of the current flowing through the amplification means based on the output result of the charging means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram for explaining this recording / amplifying circuit, FIG. 2 is a diagram for explaining the operation of this recording / amplifying circuit,
FIG. 3 is a diagram for explaining the charging means. Hereinafter, a recording amplifier circuit according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the recording / amplifying circuit according to the present invention is a recording / amplifying circuit used in a magnetic recording apparatus for recording a digital signal supplied to a rotary head via a rotary transformer 1 on a magnetic tape. Amplifying means (buffer 3, pulse transformer 2, transistors Q1, Q2, power supply Vcc) for supplying a predetermined current to the rotary transformer 1 based on the recording signal, and detecting means 4 for detecting an edge of the recording signal, A charging means 5 having a characteristic opposite to the low frequency cutoff characteristic of the rotary transformer for charging the current to a target value based on the detection result of the detection means 4.
And the amplifying means based on the output result of the charging means 5.
2, 3, Q1, Q2, and control means 6 for variably controlling the value of the current flowing through Vcc.

A recording signal obtained by modulating a digitized information signal by a modulating circuit (not shown) is supplied to the recording amplifying circuit (recording signal input in FIG. 1). This recording signal, as shown in FIG.
3, Q1, Q2, Vcc, and are supplied to the detection means 5. here,
This amplification means consists of pulse transformer 2, buffer 3, power supply
It consists of Vcc and transistors Q1 and Q2.
A current generated on the secondary side of the pulse transformer 2 by a constant current supplied from the power source Vcc is supplied to the rotary transformer 1 as a recording signal.

At this time, assuming that the current supplied from the power source Vcc is supplied to the control means 6 via the pulse transformer 2 and the transistors Q1 and Q2, respectively,
The following relationship is established between the currents I1 and I2 flowing through Q1 and Q2 and the current I3 supplied to the control means 6, respectively.

I1 + I2 = I3 For example, the recording signal is "H
If it is a signal of "i", the buffer 3 is
The signal "i" is supplied to the transistor Q1 to turn it on. The buffer 3 also supplies a signal obtained by inverting the signal "Hi" to the transistor Q2.
Set to F state.

The above currents I1 and I2 are supplied to the transistors Q1 and Q2 from the power source Vcc via the pulse transformer 2, respectively. As described above, the current I1 flows when the transistor Q1 is in the ON state. Transistor Q2 is OF
Since the current I2 does not flow due to the state of F, the current I3 supplied to the control means 6 becomes equal to the current I1 (that is, I1 = I3).

At this time, when the recording signal supplied to the detecting means 5 is, for example, a signal as shown in FIG. 2A, the detecting means 5 detects the rising or falling of this recording signal. The detection signal (shown in FIG. 2B) is supplied to the charging means 5.

The charging means 5 is, for example, a charging circuit having an electronic switch sw as shown in FIG. The charging circuit charges the current to a predetermined target value with the same time constant as the low frequency cutoff characteristic of the rotary transformer 1 described above, and supplies the current to the control means 6 via an amplifier 7 that amplifies the current to a predetermined level. Supply.

At this time, the above-mentioned detection signal is supplied to the electronic switch sw constituting the charging means 5. The electronic switch sw resets the charge by short-circuiting the charging means 5 by the detection signal, so that the current supplied to the control means 6 is as shown in FIG. 2 (C), for example.

The control means 6 varies the current value of the current I3 based on the output result of the charging means 5. That is, the charging means 5
The current output by the rotary transformer 1 is as described above.
In accordance with the low frequency cutoff characteristic of, the current is increased with the characteristic opposite to the cutoff current, and the current I3 is increased (that is, the current I1 is increased because I1 = I3). Thus, by increasing the current generated on the secondary side of the pulse transformer 2 with the increase of the current I3, the recording signal interrupted by the rotary transformer 1 is compensated, and the recording signal having a frequency component up to DC is obtained. Can be recorded (the direction of the current I1 is, for example, a recording signal "Hi"). Then, the recording signal in which the low frequency component is compensated can be recorded on the magnetic tape via the rotary head.

When the recording signal is inverted from the "Hi" signal to the "Low" signal, the transistor
Q2 is turned on, current I2 flows, and the transistor
Q1 is turned off (that is, I2 = I3), the current generated on the secondary side of the pulse transformer 2 by the control means 6 is increased in the opposite direction to the above, and the rotary transformer 1 shuts off the recording. It is possible to compensate a signal and record a recording signal having a frequency component up to DC (current I
The direction of 2 becomes opposite to the direction of the current I1 described above and becomes the recording signal "Low").

Here, the charging means 5 and the control means 6 described above.
It is assumed that an adder (not shown) is provided between and. The signal output from the recording current control means (not shown) is supplied to the adder together with the signal output from the charging means 5 described above. The adder adds the signal output from the recording current control means to the charging means. The currents output by 5 are added and supplied to the control means 6. That is,
The signal output from the recording current control means is added to the signal waveform shown in FIG. 2C and supplied to the control means 6.

The recording current control means is, for example, means for determining the recording current supplied to the rotary head, and supplies the recording current to the rotary head which is not interrupted by the low frequency cutoff of the rotary transformer. Current control means. That is, the recording amplifying circuit compensates the recording current determined by the recording current control means by the detection means 4 and the charging means 5 when the recording current is cut off by the low frequency cutoff of the rotary transformer.

Further, as described above, since the recording / amplifying circuit of the present invention can compensate the recording signal of the low frequency and record it on the magnetic tape, it is not necessary to use the modulation system for giving the recording signal redundancy. Therefore, it can be said that the improvement of the recording density of the magnetic tape is not limited.

In this recording amplifier circuit, since the recording signal in which the low frequency cutoff characteristic of the rotary transformer is compensated for is obtained by using the switching operation of the transistor, the pulse transformer and the transistor constituting the amplifying means can operate at high speed. Of course, the high speed operation of the recording / amplifying circuit can be further performed only by replacing the recording / amplifying circuit with another one.

Therefore, it goes without saying that the present recording / amplifying circuit is not limited to a special type among various pulse transformers and transistors.

[0028]

As described above, according to the configuration of the present invention as set forth in claim 1, in particular, since it has the control means for variably controlling the current value flowing in the amplifying means based on the output result of the charging means, the high speed operation is achieved. In addition, since it is not necessary to use an amplifying means having good linearity, it is possible to solve the conventional problems of high cost and poor power efficiency, and obtain a recording signal that compensates the low frequency cutoff characteristic of the rotary transformer with a simple configuration. There is an effect that can be.

Further, according to the configuration of the present invention, it becomes possible to obtain a recording signal in which the low frequency cutoff characteristic of the rotary transformer is compensated even when the digital signal is recorded by using the modulation method having no DC component. There is an effect that the error rate of the above-mentioned modulation method can be improved.

Further, according to the structure of the present invention, the reversal of the magnetization can be correctly recorded on the magnetic tape by the recording signal which compensates the low frequency cutoff characteristic of the rotary transformer, so that this can be reproduced later. In the obtained differential waveform, even if the reproduction signal is detected by the partial response method that does not reproduce the DC component, it is possible to perform the suitable reproduction, and also to perform the accurate reproduction even in the integral detection method that reproduces the DC component. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining the recording amplifier circuit.

FIG. 2 is a diagram for explaining the operation of the present recording amplifier circuit.

FIG. 3 is a diagram for explaining a charging means.

[Explanation of symbols]

 1 Rotary Transformer 2 Pulse Transformer (Amplifying Means) 3 Buffer (Amplifying Means) 4 Detecting Means 5 Charging Means 6 Control Means Q1, Q2 Transistors (Amplifying Means) Vcc Power Supply (Amplifying Means)

Claims (1)

[Claims] 1. A recording amplifier circuit used in a magnetic recording apparatus for recording a digital signal supplied to a rotary head via a rotary transformer on a magnetic tape, wherein a predetermined current is applied to the rotary transformer based on the recording signal. Amplifying means for supplying, detecting means for detecting an edge of the recording signal, and a low frequency cutoff characteristic of the rotary transformer for charging an electric current to a target value based on a detection result of the detecting means, and an inverse characteristic. A recording and amplifying circuit comprising: charging means; and control means for variably controlling a current value flowing through the amplifying means based on an output result of the charging means.