JPS6064515A - Variable amplitude equalizer - Google Patents

Abstract

PURPOSE:To obtain variable amplitude equalizer possible for correction through either of positive and negative primary slopes by controlling separately the Q of plural resonance circuits. CONSTITUTION:A voltage of +12V is applied to a terminal 22 and a voltage of +6V is fed to a terminal 23 and values of resistors 2-4 are selected so that a voltage at a point (a) is +6.5V and a voltage at a point (b) is +5.5V. Pin diodes 7, 8 are nonconductive in this state, the Q of the resonance circuit comprising a coil 5 and a capacitor 9 and the Q of a resonance comprising the coil 5 and a capacitor 10 are made nearly identical and the characteristic 1 is obtained. In applying a voltage of +12V to the terminal 23, the pin diode 7 is turned off and the pin diode 8 is turned on, the Q values are made different and the synthesized amplitude characteristic having a linear slope as shown in the characteristic 2 is obtained. In bringing the voltage of the terminal 23 to zero, the pin diode 7 is turned on and the diode 8 in turned off conversely, then the synthesized amplitude characteristic having a slope as shown in the characteristic 3 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION la) 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) Conventional technology and problems FIG. 1 shows a conventional example of an amplitude equalizer.

Since ta) in the same figure is a fixed amplitude equalizer, the amount of amplitude equalization and the direction of the slope of the amplitude characteristic are fixed. For example, when amplitude equalization is required during testing of a wireless device, a large number of equalization amounts must be prepared because the amplitude equalization amount and the direction of the slope of the amplitude characteristic vary.

On the other hand, in the case of Figure 1), the dotted line part in Figure 1 +8) is a double variable attenuator, so the amount of amplitude equalization is variable, but only the positive or negative amplitude slope 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, there is a problem in that a plurality of conventional amplitude equalizers must be prepared for a wireless device under test, and mounting locations are limited.

(C) Purpose of the Invention The present invention was devised in view of the above-mentioned problems of the prior art, and it is possible to continuously change the amount of amplitude equalization by controlling the DC voltage, and to change the amplitude equalization amount regardless of whether it is a positive or negative linear slope. The purpose is to provide a variable amplitude equalizer that allows correction.

ldl Arrangement of the Invention The above object of the invention is achieved by providing a variable amplitude equalizer having means for connecting a plurality of resonant circuits in parallel and means for separately controlling the Q of the resonant circuits.

tel　Embodiments 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 coil, 6 is a thermistor, 7 and 8 are pin diodes,
9 to 11 each represent a capacitor, and 20 to 23 each represent a terminal.

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 capacitor 9. Pin diode 7 and capacitor 10. Each is connected to a terminal 23 via a pin diode 8.

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

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

First, it is assumed that the resonant frequency r of the series resonant circuit made up of the wire 5 and the capacitor 10 is much higher than the resonant frequency fL of the series resonant circuit made up of the wire 5 and the capacitor 9.

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

f, = 1 / 2・π・(L,・C,>f, 4=
1/2·π·(L, -C)'''Here, L is the inductance of the coil 5, and C1 and C2 are the capacitance values of the capacitors 9 and 10, respectively.

Also, the input voltage of terminal 20 is J, and the output voltage of J% terminal 21 is E. Assuming U□, this ratio is as follows.

(EOLIT/EIIJ) ='C(Z+・Zi)
/ (z, +z,)ko/[R,+ (Z,・z,)/
(Z, 10Z2) 'l...-(11Here, Zl-Rd, + j (ωL, -1/ωc,), Z
z= Rda +J (ωL, -1/ωC2), Rd
, Rd represent the resistance value of the pin diode 7.8 in the high frequency range, and R1 represents the resistance value of the resistor 1, respectively.

Here, by changing the value of the voltage applied to the terminals 22 and 23, the values of the resistance bone R peak and Rd at high frequency of the pin diodes 7 and 8 of the +11 type are changed, and the synthesized amplitude characteristic is It is possible to change the level to either a flat, positive millimeter or a negative slope, and it is also possible to keep the level change constant.

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

First, apply +12V to terminal 22 in Figure 2 and +6V to terminal 23.
Adding the voltages of ■, the voltage at point a becomes +6.5■, and b
Select the resistance values of resistors 2゜3 and 4 so that the voltage at the point becomes +5.5■.

In this state, only a small amount of current flows through the pin diodes 7 and 8, so that the resistors of the pin diodes have a high resistance, and the Q's of the two series resonant circuits become approximately the same. Therefore, as shown in FIG. 3 (3), a nearly flat composite width characteristic between the series resonance frequency rL and fHO can be obtained.

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

Therefore, the Q of the series resonant circuit consisting of the wire 5 and the capacitor 9 is the Q of the series resonant circuit consisting of the wire 5 and the capacitor 10.
Therefore, a composite amplitude characteristic having a first-order slope as shown in the dotted line shown in FIG. 3 is obtained.

Also, if the voltage at terminal 23 is set to 0■, the pin diode 8 will be cut off, and a large current will flow through the pin diode 7, which will be the opposite of Figure 3■, as shown in Figure 3■. A composite amplitude characteristic with a slope is obtained.

(f) According to the present invention, as described in the detailed description of the invention, series resonant circuits are provided at the higher and lower end of the frequency band to be corrected, and each of the series resonant circuits is connected in series with each other. A variable amplitude system in which the Q of the series resonant circuit described above is changed separately by passing bias current through the pin diodes separately, so that the combined amplitude characteristic has a flat or -order slope, and the combined impedance does not change much. By using an equalizer, 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 downsizing. It is possible to aim for

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional example of an amplitude equalizer, FIG. 2 is a diagram showing an embodiment of the present invention, and FIG. 3 is a diagram for explaining the operation of FIG. 2. 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. . Akira 1 Figure (α) Ding (1))

Claims (1)

[Claims] A variable amplitude equalizer comprising means for connecting a plurality of resonant circuits in parallel and means for separately controlling Q of the resonant circuits.