JPS5972211A - Gain variation system of servo filter amplifier - Google Patents

Abstract

PURPOSE:To prevent variation in servo band width with a loop gain by allowing the 1st cutoff point to follow up gain variation and eliminating the need for the 2nd cutoff point. CONSTITUTION:A servo filter amplifier is so constituted that the 1st cutoff point follows up variation in gain and the 2nd cutoff point is independent of the gain variation. This circuit consists of, for example, an input terminal 1, output terminal 2, operational amplifiers 3 and 5, variable resistor 4 for varying the gain, capacitor C, and the filter composed of a capacitor C and resistances R1- R3, and R5. Then, when T1=C.(R3+A.R1) (A; DC gain) and T2=C.R3, the DC gain A and the 1st cutoff point 1/T1 vary by adjusting the variable resistor 4, but the 2nd cutoff point 1/T2 does not vary. A servo system using this circuit has no variation in servo band width.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable gain system for a sub-filter amplifier for a gantry drive system such as a radar.

Conventionally, there is one shown in FIG. 1 as this type of ther-e filter amplifier.

In Fig. 1, l is an input terminal, 2 is an output terminal, 3 is an operational amplifier, and 4 is a variable resistor whose dyne is variable (the resistance value divided by the slider is R4 and R5). , C
and R1, R2, and R3 are capacitors and resistors that constitute a filter.

A signal input from input terminal l is connected to operational amplifier 3, capacitor C, resistors R1 to R3, and variable resistor 4 (R4, R5).
) is output to the output terminal 2 through a filter. The gain of this circuit can be changed by adjusting the variable resistor 4 and changing the ratio of the resistance values R4 and R5.

The transfer function G (El) of this circuit is expressed by the following equation.

Here, A is DC Gui/Ashi, and the first cutoff point is 1
/1r11 The second force and the to-off point are expressed as 1/T3, and are each expressed by the following equation.

A=-・(1+-) ・・・・・・・・・・・・・・・
・・・・・・・・・(2) RI R5 't'l=c・(R2+R3)・・・・・・・・・・・・
・・Town・・・・・・・・・・・・・・・(3) T2=C
-R3・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・(4
) From Kaminichi's equations, ω<1. /Tt when IG(8)I
When =mu・ω＞1/'h, IG(S)'=A" R2
+R3.

In other words, the first point and to-off point 1. /lr l and the gain at the second cutoff point 1//TI'3 changes. This is illustrated in Figure 2.

As is clear from FIG. 2, in the servo system using the circuit shown in FIG. 1, the loss width characteristic shifts in parallel as the DC gain A changes.

This state is shown on the date diagram of the entire servo system as shown in FIG. As is clear from Fig. 3, the cutoff frequency changes from ωe1 to ωc as the loop gain changes.
2, the servo bandwidth also changes as the loop gain changes.

Therefore, when attempting to vary the loop gain of the servo system using the conventional circuit, there is a drawback in that the servo bandwidth must also be adjusted in accordance with the change in the loop gain.

The purpose of this concern is that when the loop gain is made variable, the servo and pitch widths do not change! Embodiments of the present invention will now be described with reference to FIGS. 4 to 6, in order to obtain a caustic subfilter.

In Fig. 4, l is an input terminal, 2 is an output terminal, 3 and 5 are liquid amplifiers, and 4 is a variable resistor with variable gain (
Let R4 be the resistance value after setting by the JW exciter. ), C and R1-R3, R5 are capacitors and resistors for curing the filter.

The signal input from the input terminal 1 is input to the amplifier 3゜5, the capacitor C, the resistors R1, R3, R5, and the variable resistor 4.
(R4) is outputted to the output terminal 2 through the filter. Dyneing of this circuit is performed by adjusting the variable resistor 4 to variably adjust the resistance value R4.

Further, when the transfer function G@) of this circuit is determined by circuit analysis, it becomes as shown in the following equation.

R2R5 However, A=R1・(l+−1lr4−)・・Song・・・
...(6) T1=C・(R3+A・R1) Song/between songs...(7) Ta = CllRa song...
Song/song interval...song/beat...song/song (8) In each of the above formulas, A, ]/'r, and VT are the same as in the prior art example.

From the above formulas, when ω< 1/T *, then l G(S)l
= A.

When ω>i/T 2, IG(S)l=″−(A)0 and 1.).

That is, due to the vA adjustment of the variable resistor 4, the DC dyne A and the first cutoff point 1 are
/T1 changes, but the DC gain A and the second cutoff point 1/T2 do not change for signals with a frequency of N 1/'r or higher. This is illustrated in Figure 5.

As is clear from Fig. 5, in the circuit using the circuit shown in Fig. 4, the first cutoff point changes as i/T 1 e 1/T 1' as the DC gain A changes. This is also clear from equation (7) above. ), the second cutoff point (1/T) remains unchanged.

This state is d? of the entire servo system? - If shown on the diagram, the 6th
It will look like the figure. As is clear from FIG. 6, the cutoff frequency ω. does not change depending on the change in DC gain A. Therefore, the servo bandwidth does not change.

In other words, in the circuit filter amplifier according to the present invention, only the loop gain of the circuit system is variable by adjusting the variable resistor 4, but the circuit bandwidth remains unchanged.

As described above, by using the dyne variable type circuit according to the present invention, the loop gain and the servo system can be improved. Since each band width can be set separately, the design and adjustment of the servo system becomes extremely easy.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional servo filter amplifier, Figure 2 is a characteristic diagram of a conventional servo filter amplifier, and Figure 3 is a servo system using a conventional servo filter amplifier. Fig. 4 is a circuit diagram of a servo filter amplifier according to an embodiment of the present invention, Fig. 5 is a characteristic diagram of a servo filter amplifier according to an embodiment of the present invention, and Fig. It is a Bode diagram of a servo system using a servo filter amplifier according to an example.■...Input terminal, 2...Blade terminal, 3.
5... Operational amplifier, 4... Variable resistor ◇ Figure 2 Figure 4 Procedural amendment September 1981 9 Showa dai 11'+i'+' Original r1 1st y22
67 No. 3, the name of correction! Relationship with 1v A'1 Applicant 4, Agent A1. Location East J + L Tokyo R - Dai I11 Ward Marunouchi 2 j'
l: No. 16 No. 2- Marunouchi to Shigesu Hill 330 supplement
Correct Soichi Unkiln Details W 26 and 1”riL cut” in the drawing: cr
I would like to correct it first. Note 1, page 4, line 12, 2, line 2 from the bottom of page 4, it says, ``Same as.'' Similarly, it indicates the DC voltage, the first voltage point, and the second voltage point, respectively. ” and correction 1-ru.

Claims (1)

[Claims] ff1l A dyne variable method of a subfilter amplifier in which the power cut-off point changes following the change in gain, and the second power and turn-off point remain unchanged with respect to the change in gain.