JPS63296472A - Signal correcting circuit device - Google Patents

Abstract

PURPOSE:To easily correct a signal whose low frequency component is attenuated with a simple circuit constitution by respectively and independently adjusting the inclination of an inclining part in the frequency characteristic of a gain and the frequency of a border point between the inclining part and a constant part with an integrating means and an adding means. CONSTITUTION:The integrating means 1 to integrate a signal inputted from an input part and the adding means 2 to respectively multiply an output signal from the integrating means 1 and the signal inputted from the input part by prescribed times, after that, mutually add and output them are provided thereon. A gain is GL in a low frequency area, GH in a high frequency area and comes to be constant (GL>GH), in a middle area L1, an attenuating characteristic to have a negative inclination is obtained and an angular frequency omega1 and angular frequency omega2 come to be omega1=1/C2.R1, omega2=1/C2.R1(1+R7/R6). Accordingly, even a signal with sag distortion received from any low frequency attenuation can be corrected and adjustment is easy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a signal correction circuit device that corrects a signal in which low frequency components are attenuated.

[Prior Art] FIG. 2 is a circuit diagram of a conventional signal correction circuit device that corrects sag distortion caused by attenuation of low frequency components of an image signal.

In the figure, the input terminal I11 to which the image signal is input is
It is connected to the power supply terminal 11 via a resistor R11, and is grounded via a resistor R12. Resistance R1
1 and R12 are for applying a bias voltage to the input signal. Further, the transistor Qll is for amplifying the image signal, and its base is connected to the input terminal Il.
1, and its emitter is grounded via a resistor R13. The resistor R13 is for stabilizing the transistor Qll. Furthermore, the collector of the transistor Q11 is connected to the power supply terminal V12 via load resistors R14 and R15.
The connection point between resistor R14 and resistor R15 is grounded via load capacitor C1l. The connection point between the collector of the transistor Qll and the resistor R14 is an output terminal 011.

Next, the operation of this signal correction circuit device will be explained.

For example, an image signal with flat frequency characteristics is input to the input terminal Ill. This image signal is transmitted through the resistors R11 and R1
2 and input to transistor Qll. The signal is then amplified by transistor Qll and applied to load resistors R14, R15 and load capacitor C11. In the low frequency range, the image signal applied to these loads is output in a magnitude proportional to the combined resistance of resistor R14 and resistor R15, and in the high frequency domain, the magnitude is proportional to resistor R14 because capacitor C11 has a low impedance. output in the same size.

FIG. 3 shows the frequency characteristics of the signal correction circuit device shown in FIG. 2. In the figure, the vertical axis represents the ratio of output voltage to input voltage in decibels, and the horizontal axis represents angular frequency.

As shown in the figure, the ratio of the output voltage to the input voltage, that is, the gain, is GL in the low frequency region, G in the high frequency region,
(GL > GM), and the intermediate region L1 exhibits attenuation characteristics. ω indicates the angular frequency at a point attenuated by 3 [dB] from the gain GL in the low frequency region, and ω2 indicates the angular frequency attenuated by 3 [dB] from the gain G) in the high frequency region.
[dB] indicates the angular frequency at the point of increase.

The angular frequencies ω1 and ω2 are expressed as follows.

ω+ -1/C+,・R+s...(
1) ω2-1/C,,・R+ 4 +1 / C+ +
Fist RII...(2) Here, C1, is the capacitance value of capacitor C1l, R, 4,
R, , are the resistance values of the resistors R14 and R15, respectively.

However, since the vertical axis in Figure 3 is expressed in logarithms, the above 3
The attenuation bones and increments in [dB] are not shown in the figure.

Next, FIG. 4 is a diagram showing the frequency characteristics of the filter circuit, where the vertical axis shows the gain and the horizontal axis shows the angular frequency.

As shown in the figure, the gain increases at a constant slope in a region L2 of frequencies lower than the angular frequency ω, and remains constant in the region of frequencies higher than the angular frequency ω2.

Consider the case where an image signal with sag distortion output through a filter having frequency characteristics as shown in FIG. 4 is input to the signal correction circuit device shown in FIG. 3.

In this case, the angular frequency ω2 in FIG. 3 and the angular frequency ω shown in FIG. By matching the slope of region L1 shown in FIG. 3 with the slope of region L2 in FIG. 4, it is possible to correct the image signal within the angular frequency range of region L1 in FIG. Become.

[Problems to be Solved by the Invention] When using the conventional signal correction circuit device as described above to correct an image signal that has passed through a filter having frequency characteristics as shown in FIG. So, the angular frequency ω2
and ω3, and the slope of region L1 and region L2
It is necessary to match the slope of Here, the angular frequency ω in FIG.

and assuming that the slope of region L2 is unknown, the second
In the circuit shown in the figure, it is necessary to make the resistors R14 and R15 variable to adjust the angular frequency ω2 and the slope of the region L1.

However, if one of the resistors R14 and R15 is changed to change the angular frequency ω2, the slope of the head area L1 will also change at the same time, making it impossible to set both the angular frequency ω2 and the slope of the area L1 to predetermined values. The problem was that it was extremely difficult.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a signal correction circuit device in which frequency characteristics can be easily set.

[Means for Solving the Problems] A signal correction circuit device according to the present invention includes an input section for inputting a signal, an integrating means for integrating a signal inputted from the input section, and an input section for inputting a signal from the integrating means. The apparatus further includes an adding means for multiplying the output signal and the signal input from the input section by a predetermined value, respectively, and adding the resultant signal and outputting the resultant signal. The integrating means has a variable integral coefficient. Further, the adding means has a variable magnification when multiplying each signal by a predetermined value.

[Operation] The frequency characteristic of the gain obtained by the signal correction circuit device according to the present invention has a negative slope in a frequency range lower than a predetermined frequency, and has a slope of 0 in a frequency range higher than the predetermined frequency. becomes. In this signal correction circuit device, the slope can be adjusted by changing the magnification in the adding means, and the predetermined frequency can be adjusted by changing the coefficient in the integrating means.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of a signal correction circuit device according to the present invention.

In the figure, an integrating circuit 1 is connected to an input terminal 11 to which an image signal is input via a capacitor C1 that passes only the signal component. This integrating circuit 1 is composed of resistors R1, R2 and capacitors C2, C3, one end of resistor R1 is connected to capacitor C1, and the other end of resistor R1 is grounded via capacitor C2. Also, this resistance R
One end of a resistor R2 and a capacitor C3 connected in parallel are connected to the other end of the capacitor C3.

The connection point between the resistor R2 and the other end of the capacitor C3 is
It is connected to the bias power supply terminal v1 via a resistor R3, grounded via a resistor R4, and connected to the base of the transistor Q1. Resistors R3 and R4 are for applying a bias voltage to the signal.

The collector of the transistor Q1 is connected to a power supply terminal v21, and the emitter is grounded via a resistor R5 for obtaining an output voltage. Collector of transistor Q1 and resistor R
5 is connected to the adder circuit 2 via a capacitor C4. The adder circuit 2 is composed of a resistor R6 and a resistor R7, and one end of the resistor R6 is connected to the capacitor C.
One end of the resistor R7 is connected to the input terminal 11 via the capacitor C5, and the other ends of the resistor R6 and the resistor R7 are connected to each other to form an output terminal 01.

Next, the operation of this signal correction circuit device will be explained.

First, a case will be described in which an image signal output after passing through a filter having flat frequency characteristics is input to the input terminal (1).

The image signal input to input terminal ■1 is transferred to capacitor C1.
and the first path through the integrating circuit 1 and the capacitor C5
After passing through the second path, the signals are added by the adder circuit 2 and output from the output terminal 01.

In the first path, the image signal is first transferred to the capacitor C1.
Only the signal component is passed through, and the signal component is integrated by the integrating circuit 1. The signal output from integrating circuit 1 is biased by resistors R3 and R4 and applied to transistor Q1. After that signal is buffered by the transistor Q1, only the signal component is added to the resistor R6 of the adder circuit 2 by the capacitor C4.

On the other hand, in the second path, the image signal is connected to the capacitor C
5 allows only the signal component to pass, and the signal component is added to the resistor R7 of the adder circuit 2.

The signal that has passed through the first path and the signal that has come through the second path are adjusted to a constant magnitude by the resistance values of resistor R6 and resistor R7 of adder circuit 2, and then are added together and output. It is output from terminal 01.

In the case of a signal in a high frequency region, an output signal having a magnitude obtained by adding the signal passing through the first path and the signal passing through the second path by the adder circuit 2 is obtained. On the other hand, in the case of a signal in the low frequency range, the signal passing through the first path becomes smaller because it passes through the integrator 1, and the output signal from the adder circuit 2 is approximately the same as the signal passing only through the first path. It becomes the size.

This is illustrated in the figure. Similar to the conventional signal correction circuit device shown in FIG. 2, frequency characteristics as shown in FIG. 3 are obtained. In other words, the gain is GL in the low frequency region and GM in the high frequency region and is constant (GL > G
M), the attenuation characteristic has a negative slope in the intermediate region L1. In this example, the angular frequency ω at a point attenuated by 3 [dB] from the gain GL in the low frequency region, and the gain GH in the high frequency region
The angular frequency ω2 at the point where the angular frequency ω2 increases by 3 [dB] from ω is given by the following equation.

ω+-1/Cz・R1...(3) ω2-1/C2・R4' (1+Rt/R6)・
...(4) Here, R, , R6, and Rf are the resistances R, respectively.
1, the resistance values of R6, and R7, and C2 is the capacitance value of the capacitor C2.

From the above formulas (3) and (4), the capacitance value C2 of capacitor C2
Assuming that ω is constant, the slope in the region L1 of FIG.
2 is determined.

Therefore, an image signal with sag distortion that has passed through a filter having the frequency characteristics shown in FIG. Become.

According to the signal correction circuit device of this embodiment, the noise caused by the variable resistor is removed by the capacitor C2 of the integrating circuit 1 and does not appear in the output.

Furthermore, if the resistor R1 of the integrating circuit 1 and the resistor R6 of the adding circuit 2 are variable resistors, the slope of the region L1 in FIG. 3 can be adjusted by the resistor R6, and the angular frequency ω2 can be adjusted by the resistor R1. .

Therefore, it is possible to correct any signal with sag distortion that has undergone low frequency attenuation, and adjustment is easy.

[Effects of the Invention] As described above, according to the present invention, the slope of the slope portion in the frequency characteristic of the gain and the frequency of the boundary point between the slope portion and the constant portion are independently adjusted by the integrating means and the adding means. Therefore, a signal with attenuated low frequency components can be easily corrected with a simple circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the signal correction circuit device according to the present invention, FIG. 2 is a circuit diagram of a conventional signal correction circuit device, and FIG. 3 is a circuit diagram of the signal correction circuit device of FIGS. 1 and 2. A diagram for explaining frequency characteristics, FIG. 4 is a diagram showing frequency characteristics of a filter. In the figure, 1 is an integrating circuit, 2 is an adder circuit, 11 is an input terminal, 01 is an output terminal, R1-R7 are resistors, 01 to C5
is a capacitor, Ql is a transistor, and Vl and V2 are power supply terminals. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (5)

[Claims] (1) A signal correction circuit device that corrects a signal in which low frequency components have been attenuated, comprising: an input section into which the signal is input; and an integral whose coefficient is variable and which integrates the signal input from the input section. A signal correction circuit device comprising: a means for multiplying the output signal from the integrating means and the signal input from the input section by a predetermined value, and then adding them together and outputting the results, and whose multiplying factor is variable. . (2) The signal in which the low frequency component is attenuated is an image signal having sag distortion.
The signal correction circuit device described in . (3) The signal correction circuit device according to claim 1 or 2, wherein the integrating means is comprised of a resistor and a capacitor. (4) The signal correction circuit device according to claim 3, wherein the resistance of the integrating means is a variable resistance. (5) The adding means includes a first resistor and a second resistor, one end of the first resistor is connected to the input section, and one end of the second resistor is connected to the output terminal of the integrating means. the other end of the first resistor and the other end of the second resistor are connected to serve as an output terminal;
5. The signal correction circuit device according to claim 1, wherein the resistor is a variable resistor.