SU1497662A1 - Electrically-controlled attenuator - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to increase the insertion loss, reduce the initial loss and decrease the temperature dependence of the insertion loss. The attenuator contains segment 1 of the transmission line, at the input and output of which the L-shaped links of diodes 2 and 3 and diodes 4 and 5 are included. Diodes 6–9 are parallel connected between these links in segment 1. In this case, the link consisting of diodes 2 and 4 is coordinated from the input side of the attenuator, and the link consisting of diodes 3 and 5 is coordinated from the output side of the attenuator. The control current supply circuits consist of coupling capacitors 10–13 and termination resistors 14 and 15. The chokes 17–21 and blocking capacitors 24–28 are used for microwave breakdown. In this attenuator, in the mode of maximum attenuation, diodes 2 and 3 carry the most current, and a small current flows through diodes 4 and 5 or they are de-energized. When the attenuation decreases, the current through the diodes 6-9 decreases, and the current through the diodes 4 and 5 increases according to a certain law, ensuring coordination and low dependence of attenuation on the frequency. 1 hp ff, 2 ill.

Description

3149

Ichbrestenie refers to microwave radio technology, for example, to a measuring technique for building readout attenuators with a small dependence

applied attenuation from frequency.

The purpose of the invention is to increase the insertion attenuation and decrease the loss of losses, as well as reduce the temperature dependence of the insertion attenuation,

Fig. 1 shows an electrically controlled attenuator; Fig. 2 is a diagram when the closest to the third diode in the output L-shaped link is the first diode.

The electrically controlled attenuator contains a segment of 1 transmission line, at the input and output of which the I-oCpasHbie signal is included from the first 2 and 3 and second 4 and 5 diodes. Between the L-shaped links in segment 1, the third diodes 6-9 are connected in parallel. Moreover, the L-shaped link consisting of the first 2 and second 4 diodes is according to the input side of the attenuator, and the L-shaped link consisting of the first 3 and second 5 diodes agreed with the output attenuator.

The control current supply circuits include isolating capacitors 10–13, terminating resistors 14–16. Throttles 1 7-23 and blocking capacitors 24-30 serve as the single high frequency microwave. The distance between the extreme third diodes 6 and 9 and the second diodes 4 and 5 closest to them are no more than 0.13 selected. FIG. 2, the distance between the extreme diode 7 and the first diode 3 closest to it is chosen from the condition (o, 16 - 0.28) / j,. In this case, the impedance of the second diodes 4 and 5 with large attenuations was chosen capacitive, and their temperature dependence was chosen higher than the temperature dependence of the first and third diodes 2, 3 and 6–9.

The electrically controlled 1st attenuator operates as follows.

In the maximum attenuation mode, a small current flows through the first diodes 2 and 3, and a small current flows through the second diodes 4 and 5 or it is de-energized.

The insertion of a weakening is formed by the following terms 1x.

The attenuation created by the third diodes 6–9 increases with increasing frequency from to the frequency at which

0

five

0

five

62

;

dz

,

yy

thirty

35

40

four

The position between them is equal to a quarter of the VI wave, with a further increase in the frequency, the attenuation decreases.

The attenuation created by the second diodes 4 and 5. Each of them in a de-energized state is a small capacitance, and the insertion attenuation decreases with increasing frequency until the impedance of diodes 4 and 5 becomes comparable with the characteristic impedance of segment 1. current through second diodes 4 and 5, their equivalent circuit is a parallel connection of capacitance, independent of the control current, and resistance, the value of which depends on the magnitude of the control current, which allows control of the slope attenuation decreases with increasing frequency, and compensates for the increasing attenuation of third diodes 6–9 with increasing frequency. In this case, the second diodes 4 and 5 are interconnected by third diodes 6–9.

The additional attenuation created by the inclusion in the immediate vicinity of the second and third diodes 4 and 6, 5 and 9, When the resistances of the second diodes 4 and 5 are large and the resistances of the third diodes 6–9 are small, the additional attenuation created by them tends to be 6 dB for each a couple and weakly dependent on frequency if the distance between them is no more than 0, when the additional attenuation is halved.

The attenuation created by the open first diodes 2 and 3, together with the terminating resistors 14 and 15, is on the order of 3-4 dB for such a chain and is weakly dependent on frequency. The chains of the first diodes 2 and 3 and the terminating resistors 14 and 15 together with the second diodes 4 and 5 provide for matching the input and output of the attenuator in a dynamic mode. When the attenuation decreases, the current through the third diodes 6-9 decreases, and the current through the second diodes A and 5 increases according to a certain law, ensuring coordination and a small dependence of attenuation on frequency.

Claims (1)

Invention Formula one . Electrically controlled (1st attenuator containing a segment of the transmission line, at the input and output of which L-shaped links from parallel and ps of the first and second diodes respectively connected are included, while between the L-shaped links parallel to the transmission line, third diodes are connected, in order to increase insertion loss and decrease initial losses, The third diodes are placed at a distance (0.16 - - 0.28), one from another, where L (, is the wavelength of the upper frequency of the operating range, and the distance between the extreme third diodes and the G-image no more than 0.13 dp in the case when the closest to the third diodes in the L-shaped links are the second diodes or (0.16 - 0.28), for the case when the closest to the third diodes in the L-shaped are selected The links are the first diodes, and the impedance of the second diodes is chosen as capacitive, 2, Attenuator according to Clause I., T.L.A.A and so that, in order to reduce the te1: temperature dependence of the applied attenuation, the second diodes are selected with a higher temperature dependence than the first and third diodes. FIG. 2