JPS601606A - Sound recording circuit - Google Patents

Abstract

PURPOSE:To avoid the variation of the sound recording level due to the heating of a sound recording head, etc. as well as the cross modulation distortions, by supplying both the signal to be sound recorded and the bias signal to the sound recording head after current amplification. CONSTITUTION:The sound recording signal supplied to an input terminal 61 is supplied to an amplifier A21 of a voltage/current converter X1; while a current having the value obtained by multiplying 1/Z1 by an input current flows to a load Z1. The variation of this current is sent to an output terminal 101 via junctures 12 and 13 and transistors Q21 and Q31. Then the output signal underwent current amplification is supplied to a recording head H3 via a juncture 11. in the same way, the bias signal is sent to an input terminal 62. Thus the current flowing to a load Z2 of a voltage/curent converter X2 has the value obtained by multiplying 1/Z2 by the input signal. The variation of said current appears to an output terminal 102 after current amplification and is sent to the head H3 to be superposed on the sound recording signal.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) The present invention relates to a recording circuit for a magnetic recording/reproducing device.

(Object of the Invention) The present invention aims to improve recording characteristics by driving a recording head with current, and also provides an edge height circuit (11t1) that can obtain predetermined characteristics without bias trapping or frequency correction.
The purpose is to do something.・(Conventional example) Figure 1 [U, Conventional recording circuit (15).

This recording circuit creates a flat recording characteristic by passing the signal to be recorded through a resonant circuit that has an impedance characteristic that is opposite to the one impedance characteristic of the recording head.
J, I'm going to do it with the Udo circuit.

As shown in Figure 2, the impedance characteristic of the recording head is inductive (as shown by the dicentric region in the figure, the impedance is higher in the high range), so it is difficult to detect the signal to be recorded. By passing the signal through a circuit with an impedance characteristic opposite to that of the head and then supplying the signal to the head, it is possible to record on a flat recorder 11.

1 to be recorded supplied to Rokuryoku Panryo 1! The signal (J) is supplied to the base of the transistor Q1 via the capacitor C1 and then inverted by jM. , to the parallel circuit of resistor R1 and capacitor C3, and to the parallel resonant circuit of coil L2 and capacitor C5 'δ, and to the recording head 1-1 via connection point 2.
1.

The parallel resonant circuit of L2 and C5 operates as a bias trap. 1-A series resonant circuit consisting of a capacitor C4 and a coil 11 is inserted in parallel with the emitter resistor between the emitter of the transistor Q1 and the ground.

The head 1-11 receives a bias signal outputted from the high frequency bias frequency 08Ch)]
Supplied via.

The parallel resonant circuit of R1 and C3, which has an impedance characteristic opposite to that of the recording head 1-11, is combined with the series resonant circuit of C4 and Ll. By making a high level signal and supplying this signal to the head 111, a flat recording characteristic can be achieved by 1q
It is possible to do so.

The above recording circuit drives the head at a constant voltage, so
When the magnetic permeability of the rectifier changes and the inductance changes due to head heat generation, etc., the input current of the head changes and the recording level changes.

FIG. 3 shows another conventional recording circuit.

This circuit can eliminate the drawbacks of the recording circuit shown in FIG. In other words, this is a recording circuit in which the recording level does not change even if the inductance of the C head changes by driving the four recording heads with current.

The signal to be recorded supplied to the input terminal 3 is supplied to the non-inverting input terminal of the amplifier A1 and then amplified there. The signal to be amplified is output from the output terminal 4,
” Parallel resonant circuit of C7, L, 3,
jΣε concatenated 5 and supplied to one end of the recording head [12]. The other end of the head 112 is grounded via a resistor R2, and connected to an amplifier Δ1 via a parallel resonant circuit of C8 via a resistor R3.
is connected to the inverting input terminal of This inverting input terminal is grounded via a resistor R1.

A bias signal output from a high frequency bias oscillator OSC is supplied to the head (-12) via a capacitor -06 and a connection point 5.

If amplifier A1 is an ideal amplifier, recording head 1
-12 is current-driven in the frequency band of the signal to be recorded. The signal to be recorded, which is fed to the input terminal J'3, is current-driven in proportion to R2(-R3,'R2.R4).

The feedback path B of the amplifier A1 includes a parallel resonant circuit d of [3・C7
3 Jζ in parallel with L4 and C8 (a bar consisting of a swing circuit, 7
Since there is an astrap circuit, the feedback at the bias frequency is
(2) decreases, and as shown in Fig. 4, the frequency vs. voltage gain of the amplifier △1 output horn is 1!7 (centering on the J bias frequency), and the voltage gain is reduced.

As described above, the bias signal output from the bias oscillator O8C of the above circuit (J) has the disadvantage that it is inundated by cross I-ring etc., and a bias signal is generated at the output of the amplifier Δ1, causing cross-modulation distortion. Ta.

(Problem that R-mei is trying to solve) The recording level changes as the input current of the recording head changes due to heat generated by the recording head.

A point that causes cross-modulation distortion in the signal that should be recorded.

(Means for Solving the Problems) A first voltage-to-current converter for current amplifying the signal to be recorded>3; A second voltage-to-current converter is used to amplify the superimposed bias signal by electric FAE, and the current is amplified by the first voltage-to-current converter. 1) The signal to be recorded 8 is the current amplified by the second voltage-to-current converter. A recording circuit characterized by a recording circuit.

(Embodiment) FIG. 5 is a diagram illustrating an embodiment of an electric current to current converter used in the recording circuit of the present invention.

FIG. 6 is a diagram illustrating a record 8 circuit as an embodiment of the Noho generator.

As shown in FIG. 5, the voltage-current converter
△2, load Z of amplifier Δ2, constant current sources CC1 and CC2,
It is made up of transistors Q2 and Q3 (j4).

A constant current source CC1 is connected to the power supply terminal 7 of the amplifier Δ2, and a constant current v? is connected to the - power supply terminal 8 thereof. , CC2 are connected. A load Z is inserted between the output terminal 9- of the amplifier A2 and the ground.

Constant current source CC1<CC2)+Jl A connected to the emitter of transistor Q2 (Q3) whose base is grounded
l-transistor Q2. Q3's 62'' rectors are connected,
A signal applied to the input terminal 6 and amplified by current is output from the output terminal 10 at the connected midpoint.

The power supply terminal 7 (-power supply terminal 8) of the amplifier A2 is connected to the emitters of transistors Q2 (Q3) through a connection point 11 (12) with a constant current source CC1 (CG2).

The current 11 from the constant current source CC1 is divided into a current i1A flowing from the connection point 11 to the amplifier A2 and a current i1B flowing to the 1-transistor Q2.

The current 11Δ is the current flowing through the terminal 7 jJ3 of the amplifier A2, its output terminal 9, and the load Z.

When a signal is applied to the input terminal 1G, the current 11Δ fluctuates due to this signal, and the current i1B also fluctuates due to this fluctuation. This fluctuation in the current N13 is transmitted to the output terminal 10 through the emitter and collector of the transistor Q2, and the output from the output terminal 10 changes depending on the applied input signal level. Kai-3 will fluctuate, and Yutan will be amplified by current.

The current 12 flowing into the constant current source CC2 is a combination of the current 12Δ from the amplifier A2 flowing into the connection point 12 and the transistor Q3.
This current is the sum of the current i23 from the current i23.

Therefore, similar to the effect of the current 11Δ described above, the current 1
2Δ varies by J due to the signal applied to the input terminal 6, and due to this variation of the current i2A, the electric current iXi, i 2
This fluctuation in the current i2Q is transmitted to the output terminal 10 via the emitter of the transistor Q3, which is the current amplification of the signal.

The recording circuit of the present invention, shown in FIG. 6, uses a voltage-current converter X for current amplifying the signal applied to J:.

In Figure 6, the voltage at which the signal to be recorded is input centered around the recording head 1-13 - 1 V! There are a voltage-current converter X1 (first voltage-current converter) and a voltage-current converter X2 (second voltage-IJ-current converter) into which a bias signal is input.

Converter X1. Since the configuration of X2 and its operation 1' are similar to the converter X shown in FIG. 5, a description thereof will be omitted.

Corresponding to amplifier A2 of converter X shown in FIG. 5 is amplifier A21. Δ22, and the load corresponding to the negative Z is 21.22'C-.

Constant current sources CC11 and CC12 1. ．． 1 power supply (-vCC
A power source -VCC is connected to each of the constant current sources CC21 and CC22. Transistor Q21. Q31.
The bases of Q22 and Q32 have a voltage E11. E21
．． E12. E22 are connected to each other.

Next, the (j;1 formation J3 of the circuit of the present invention and its operation will be explained.

The input terminal 61, to which the signal to be recorded is supplied, has a voltage -
Current converter X1. Recording head 1-1 via connection point 11
Connected to 3.

Bias oscillator O8C is connected to recording head 113 via input terminal G2, voltage-current converter X2, and connection point 11.

Assume that the transistors 1 to 1 in Figure 6 have a sufficiently large phase H conductance and a sufficiently large current amplification factor. , the same value as the signal to be recorded coming from the input terminal 61 (J) appears at the respective emitter connection point 91 of the transistors Q41, Q51. Therefore, the current flowing to the negative 4UZ1 (1 to the J input signal, /
It becomes the value multiplied by Z1. The current flowing through the load Z1, which varies depending on the level of the applied incoming signal, is passed through the transistor Q41. Since it is supplied from the 2 irctor of Q51, the fluctuation of this current is connected +', i 12 .

13.Transif, TaQ21. Q31 @Sakehenj (
15JHX 1 to the output terminal 101 of the output terminal 1 according to the level of the applied input signal.
The current amplified output signal from 01 is transmitted to recording γ1 head 1-13 via connection point 11.

In this case, it is possible to amplify the signal to be recorded with current and supply it to the recording head 1-13.

While the signal to be recorded is electrically amplified and supplied to the head 113, the bias signal superimposed on the signal to be recorded is also current amplified and supplied to the head H.
3.

The same value as the bias signal input from input terminal 62 is 1.
-Ran resistor Q42. Each of Q52 [mitter connection point 92
appears in Since this connection point 92 is grounded via the load Z2, the current flowing through the load/2 is 1.1 human power, which is 1/Z2. The current flowing through the load Z2, which changes by 1FIJ depending on the level of the applied bias signal, is the transistor Q42. Since the current is supplied from the collector of Q52, the fluctuation of this current flows through the connection points 14, 15 and transistors Q22. The current amplified output signal (J, 102/l) is transmitted to the output terminal 102 via the output terminal 102 via the output terminal 102, and the current amplified output signal (J, 102/l) is output depending on the level of the applied bias signal. Intermediate-C recording head H
3.

In this way, the bias bias is amplified with current and the recording head 1
”3.

As mentioned above, by current amplifying both the signal to be recorded and the bias signal and then supplying both signals to the recording head, it is possible to eliminate the drawbacks of the conventional recording circuit described above. .

(Effects) In addition to driving the recording head with current to improve the recording characteristics, we have proposed a recording circuit that can reduce the predetermined recording characteristics by 1η by performing bias l-wrap and frequency correction. J is a monkey.

[Brief explanation of drawings]

Figures 1 and 3 (see the conventional recording circuit diagrams,
'A) Figure 2 shows the impedance characteristic +1 of the needle height head, Figure 4 shows the frequency characteristics versus voltage gain (q-resistance diagram) of the conventional example circuit in Figure 2, and Figure 5 shows the voltage used in the record a circuit of the present invention. - A diagram showing an embodiment of a current converter, and FIG. 6 is a diagram showing a recording circuit which is an embodiment of the present invention. Δ1.Δ2.A21.Δ22...Amplifier, CC1°C
C2, CCII, CCl2. CC21, CC22...
Constant current source, G11-113... Recording head, O20.
...Bias oscillator, Q1 to Q3. O21, O22,
O31, O32゜O41, O42, O51, O52...
・1-Funjisku, X. Xl, X2-...Voltage-current converter, Z, Zl, Z2-
··load.

Claims (1)

[Claims] A first voltage for current amplifying the signal to be recorded.
a second voltage-current converter for current amplifying the bias signal superimposed on the signal to be recorded, and a current amplified by the first voltage-current converter. A recording circuit comprising: a recording head to which the signal to be recorded is supplied with the bias signal which is current amplified by the second voltage-current converter.