SU1283879A2 - Attenuator with electric control - Google Patents

Abstract

The invention relates to radio engineering. In relation to A.N. No 1078506, the insertion loss error is reduced. The device contains the transmission line 1 p-i-n diodes 2-5, the control transistor 6, the base of which is connected to the input 7 of the control voltage source, the resistive divider 8, (p-1) of the transistors 9-11. Newly introduced transistor 12 and two series-connected resistors 13 and 14. 1 sludge.

Description

(L

The invention retreats to radio engineering. peak and can be used to regulate the power in the radio equipment for various purposes.

The purpose of the invention is to reduce the insertion attenuation setting error.

In the drawing of the invention, a schematic diagram of an electrically controlled attenuator is shown.

The electrically controlled attenuator contains a transmission line 1, -in-diodes 2-5, a control transistor 6, the base of which is connected to the input 7 of the control voltage source, resistive divider 8, first, second, ..., (n-1 ) -th transistors 9, 10, 11, additional transistor 12 and two series-connected resistors 13 and 14.

Electrically controlled attenuator works as follows.

When a minimum control voltage is applied to input 7 from a source of control voltage, all transistors (12, 6, 10 and 11) are open, the maximum current flows through the pi-n-diodes 3 and 4, and the attenuation in the transmission line 1 is minimized .

As the driving voltage 1 increases, the collector currents of these transistors decrease, the current through p-1-n diodes 3 and 4 decreases, and the attenuation of the signal in transmission line 1 increases. When the control voltage reaches the threshold value and, determined by the voltage at the emitter of the first transistor 9, is reached. An additional 12 and control transistors are closed. With a further increase in the control voltage, the second 10 and the remaining (n-1) -th transistors 10 and 11 are successively closed, the current through pin diodes 3 and 4 becomes equal to zero, the signal attenuation in transmission line 1 becomes maximum, and the base-emitter voltage the transitions of the second 10, additional 12, and control 6 transistors turn out to be under reverse voltage of different magnitudes. At the same time, in order to obtain the effect of linearizing the adjustment characteristic of the attenuator, the voltage is chosen to be sufficiently small for transistors. Resistors 13 and 14 of equal magnitude shunt the reverse biased base-emitter junction of these transistors and they are under reverse voltage of equal magnitude.

{ABOUT

15

20

thirty

45

50

and

Tfe

 five--. where and

 , t Umax - Unop „Aon

- and with - and

max

Ann

Jp.

b-e

From here;

So

Б-э 2 - & -Е control voltage value at which the attenuator introduces the greatest attenuation into the transmission line

maximum permissible voltage value at the base-emitter junction of this type of transistor.

 2U

Db b-e

- and

pore

and it can be chosen greater than ian than the auth attenuator. St.

St. No. 1078506, despite the fact that the potential is pushing a pair of transistors 25 12 and 6 is greater than that of a single transistor by 0.7 B, which is why

 Unop-u ::; o, 7,

where I is the minimum threshold voltage in an attenuator according to the ed. St. N 1078506, at which the highest control voltage value is obtained, equal to

H38 Aop i, man 5-9 l1op The adjustment characteristic of the attenuator is described by the expression

35

40

t - lafJi-Z-L and

lO (x

V + L,

where LQ, is the iteri introduced by the attenuator to the transmission line in the OPEN position.

The error in setting the attenuation value can be determined as follows:

dL Ljiig LO

dV UmaT

The values of L g and L are determined by the parameters of the p-i-p-diodes, the scheme of their inclusion in the transmission line and the isolation elements in the supply circuit of the displacement on p-i-n-diodes, i.e. technical and constructive solution of high part, because of which, under the greatest volume - 55 of the total part of the attenuator and, consequently, the voltage will always be the same, the same for the given attenuator base-emitter junctions of the attenuator and attenuator according to author. St. No. 12 and control number 6 No. 1078506,

 transistors. Resistors 13 and 14 of equal magnitude shunt the reverse biased base-emitter junction of these transistors and they are under reverse voltage of equal magnitude.

five

and

Tfe

 five--. where and

 , t Umax - Unop „Aon

- and with - and

max

Ann

Jp.

b-e

Б-э 2 - & -Е control voltage value at which the attenuator introduces the greatest attenuation into the transmission line

maximum permissible voltage value at the base-emitter junction of this type of transistor.

From here;

0

0

So

 2U

Db b-e

- and

pore

and it can be chosen greater than ian than the auth attenuator. St.

St. No. 1078506, despite the fact that the potential is pushing a pair of transistors 5 12 and 6 is greater than that of a single transistor by 0.7 B, which is why

 Unop-u ::; o, 7,

where I is the minimum threshold voltage in an attenuator according to the ed. St. N 1078506, at which the highest control voltage value is obtained, equal to

H38 Aop i, man 5-9 l1op The adjustment characteristic of the attenuator is described by the expression

five

five

0

0

t - lafJi-Z-L and

lO (x

V + L,

where LQ, is the iteri introduced by the attenuator to the transmission line in the OPEN position.

The error in setting the attenuation value can be determined as follows:

dL Ljiig LO

dV UmaT

The values of L g and L are determined by the parameters of the p-i-p-diodes, the scheme of their inclusion in the transmission line and the isolation elements in the supply circuit of the displacement on p-i-n-diodes, i.e. By the technical and constructive solution of high clock. The proposed attenuator can be chosen to be N times as large as the maximum control voltage. from the attenuator on auth. St. № 1078506, where

N - (,.

i tdop 1 -,

Bao lop as real

and;, 7 i 0,7 V.

Claims (1)

In this case, the error of the attenuation setting as compared with the attenuator according to aut. St. No. 1078506 becomes less by N i, 2 times. Formula isotopic Electrically controlled attenuator by author. St. No. 1078506, characterized in that, 4TOj, in order to reduce the installation error of a cifMoro attenuation, an additional transistor and two series-connected resistors are inserted, the resistances of which are the same, the bases of p-1 transistors connected to the base of the control transistor through one of the resistors , another resistor is connected between the emitter and the base of the control transistor, and the additional transistor is connected by the emitter, collector and base respectively to the base, call | control transistor and to the bases a -1 transistors.