JPH0133965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a variable amplitude equalizer, and more particularly to a variable amplitude equalizer for primary slope correction of amplitude characteristics used in multiple radio equipment.

(b) Prior art and problems FIG. 1 shows a conventional example of an amplitude equalizer.

Since the amplitude equalizer shown in FIG. 1A is a fixed amplitude equalizer, the amount of amplitude equalization and the direction of the slope of the amplitude characteristic are determined. For example, when it is necessary to equalize the amplitude while testing a wireless device, a large number of equalizers must be prepared because the amount of amplitude equalization and the direction of the slope of the amplitude characteristic vary.

On the other hand, in the case of Figure 1b, the dotted line part in Figure 1a is a double variable attenuator, so the amount of amplitude equalization is variable, but only positive or negative amplitude slopes can be corrected. Since this is not possible, two are required.

Moreover, when these amplitude equalizers are implemented in a wireless device, they are limited in that they must be located in a location that is easy to remove and adjust.

As explained above, conventional amplitude equalizers have the problem of requiring a plurality of equalizers to be prepared for the wireless device under test, and furthermore, mounting locations are limited.

(c) Purpose of the Invention The present invention has been made in view of the problems of the prior art described above, and is capable of continuously changing the amount of amplitude equalization by controlling the DC voltage, and in addition, it is possible to change the amount of amplitude equalization continuously by controlling the DC voltage. The purpose is to provide a variable amplitude equalizer that allows correction.

(d) Structure of the Invention The purpose of the invention is to connect one wire ring, one end of which is connected to a line through which a signal to be amplitude equalized propagates, to one end of a first and second capacitor, respectively;
first and second series resonant circuits having resonant frequencies f _L and f _H by connecting the other ends of the first and second capacitors to first and second pin diodes arranged in opposite directions to each other; and the first and second direct currents are applied so that the Q of the first series resonant circuit at the resonant frequency f _L and the Q of the second series resonant circuit at the resonant frequency f _H are approximately the same. After flowing through the first and second pin diodes, the first and second DC currents whose DC current values are changed in opposite directions when the two Q's become almost the same are passed through the corresponding pin diodes. This is achieved by providing a variable amplitude equalizer configured to control the Q of the first and second series resonant circuits in opposite directions.

(e) Examples of the invention FIG. 2 is a diagram showing an embodiment of the present invention.

In the figure, 1 to 4 are resistors, 5 is a wire, 6 is a thermistor, 7 and 8 are pin diodes, 9 to 11 are capacitors, and 20 to 23 are terminals.

Each of these parts is connected as follows.

Terminal 20 is connected to terminal 21 via resistor 1, one end of coil 5 is connected to terminal 21, and the other end is connected to terminal 23 via capacitor 9, pin diode 7, capacitor 10, and pin diode 8. Ru.

Further, the terminal 22 is connected to the resistor 2, the thermistor 6, and the resistors 3 and 4, and the terminal 23 is connected to the capacitor 11.
Each is grounded via the

The outline of the operation of the circuit connected in this way is as follows.

First, the resonant frequency f _H of the second series resonant circuit composed of the coil 5, the capacitor 10, and the pin diode 8 is the same as that of the first series resonant circuit composed of the coil 5, the capacitor 9, and the pin diode 7. Suppose that it is much higher than the resonant frequency f _L of the resonant circuit.

These resonant frequencies are given by the following equations, respectively.

f _L = 1/2・π・(L ₁・C ₁ ) ^1/2 f _H = 1/2・π・(L ₁・C ₂ ) ^1/2 Here, L is the inductance of the wire ring 5, _C1 ,
C ₂ is the capacitance value of capacitors 9 and 10, respectively.

Further, if the input voltage at the terminal 20 is E _IN and the output voltage at the terminal 21 is E _OUT , then this ratio is as follows.

(E _OUT /E _IN ) = [(Z ₁・ Z ₂ ) / (Z ₁ + Z ₂ )] / [R ₁ +
(Z ₁・Z ₂ )/(Z ₁ +Z ₂ )]...(1) Here, Z ₁ = Rd ₁ + j (ωL ₁ -1/ωC ₁ ), Z ₂ = Rd ₂ + j (ωL ₁ -1 /ωC ₂ ), Rd and Rd represent the resistance values of the pin diodes 7 and 8 in the high frequency range, respectively, and R ₁ represents the resistance value of the resistor 1, respectively.

Here, by changing the value of the voltage applied to terminals 22 and 23, the values of resistance Rd ₁ and Rd ₂ at high frequency of pin diodes 7 and 8 in equation (1) are changed, and the combined The amplitude characteristic can be changed to either flat, positive slope, or negative slope, and the level change can be kept constant.

FIG. 3 is a diagram for explaining the operation of the circuit diagram of the present invention.

First, connect +12V to terminal 22 in Fig. 2, and connect terminal 23 to terminal 23.
Add a voltage of +6V to each, and the voltage at point a becomes +
6.5V, and select the resistance values of resistors 2, 3, and 4 so that the voltage at point b is +5.5V.

In this state, only a small amount of direct current flows through the pin diodes 7 and 8, so the resistance of the pin diodes becomes high, and the Q of the first and second series resonant circuits becomes approximately It will be the same. Therefore, as shown in FIG. 3, a nearly flat composite amplitude characteristic between the resonance frequencies f _L and f _H can be obtained.

Next, when the voltage at terminal 23 is set to +12V, pin diode 7 is cut off and another pin
A large current flows through the diode 8.

Therefore, the Q of the first series resonant circuit consisting of the wire 5, the capacitor 9, and the pin diode 7 is equal to the Q of the wire 5.
is larger than the Q of the second series resonant circuit consisting of capacitor 10 and pin diode 8, so
A composite amplitude characteristic having a linear slope as shown in the dotted line in FIG. 3 is obtained.

Also, if the voltage at terminal 23 is set to 0V, the pin
Since the diode 8 is cut off and a large current flows through the pin diode 7, a composite amplitude characteristic having a slope as shown in FIG. 3 is obtained, which is the opposite of that in FIG. 3.

(f) Effects of the Invention As explained above, according to the present invention, a series resonant circuit is provided for each of the higher and lower frequency bands to be corrected using a common wire ring and two capacitors, A DC current is separately applied to pin diodes connected in series in each of these series resonant circuits in opposite directions, and the Q of the series resonant circuit is
After making the values almost the same, the two Qs are controlled in opposite directions by changing the DC current values in opposite directions and flowing them through the corresponding pin diodes, so that the composite amplitude characteristic has a flat or first-order slope. In addition, a variable amplitude equalizer that does not significantly change the combined impedance is obtained. By using this, there is no need for an extra amplitude equalizer when testing and adjusting wireless equipment, and there are no restrictions on the placement of equipment when installing it in the equipment, resulting in cost reduction and equipment miniaturization. It is possible to plan.

[Brief explanation of drawings]

Figure 1 shows a conventional example of an amplitude equalizer;
The figure shows one embodiment of the present invention, and Fig. 3 shows a second embodiment of the present invention.
Diagrams for explaining the operations of the figures are shown respectively. In the figure, 1 to 4 are resistors, 5 is a wire, 6 is a thermistor, 7 and 8 are pin diodes, 9 to 11 are capacitors, and 20 to 23 are terminals. .

Claims (1)

[Claims] 1. One wire ring, one end of which is connected to a line through which a signal to be amplitude-equalized propagates, is connected to one end of a first and second capacitor, respectively, and the first and second capacitors are The other ends of the two capacitors are connected to the first and second pin diodes arranged in opposite directions to form a first and second series circuit having resonant frequencies f _L , f _H (f _L <f _H ). A resonant circuit is formed, and the first and second direct currents are connected so that the Q of the first series resonant circuit at the resonant frequency f _L and the Q of the second series resonant circuit at the resonant frequency f _H are approximately the same. After passing current through the first and second pin diodes, the DC current values when the two Qs become approximately the same are changed in opposite directions to flow through the corresponding pin diodes, and the current is passed through the corresponding pin diodes. , a variable amplitude equalizer characterized in that the Q of the second series resonant circuit is controlled in opposite directions.