SU506110A1

SU506110A1 - Controlled attenuator

Info

Publication number: SU506110A1
Application number: SU1966606A
Authority: SU
Inventors: Игорь Александрович Белозеров
Original assignee: Всесоюзный Научно-Исследовательский Институт Медицинского Приборостроения
Priority date: 1973-10-26
Filing date: 1973-10-26
Publication date: 1976-03-05

Description

1one

Изобретение относитс к радиотехнике, может использоватьс в качестве регулирующего элемента при автоматической регулировке усилени , а также в качестве модул тора .The invention relates to radio engineering, can be used as a regulating element in automatic gain control, and also as a modulator.

Известен управл емый аттенюатор, содержащий Г-образный делитель с резистором , в последовательной ветви и полевым транзистором в параллельной ветви, к затвору которого подключены два резистора, один из которых соединен с источником управл ющего напр жени .A controlled variable is known that contains an L-shaped divider with a resistor, in a series branch and a field-effect transistor in a parallel branch, to the gate of which two resistors are connected, one of which is connected to the control voltage source.

Цель изобретени - уменьшение смещени нулевого уровн под действием управл ющего напр жени .The purpose of the invention is to reduce the zero-level bias under the action of a control voltage.

В предлагаемом, аттенюаторе к выходу делител подключен операционный усилител включенный по схеме повторител напр жени , выход которого соединен со вторым, резистором.In the proposed attenuator, an operational amplifier is connected to the output of the divider in accordance with a voltage follower circuit whose output is connected to the second resistor.

На чертеже приведена принпипиальна электрическа схема аттенюатора.The drawing shows an electrical attenuator circuit.

Управл емый аттенюатор содержит Г-образный делитель с резистором, 1 в последовательной ветви и полевым, транзистором 2 в параллельной ветви, к затвору которого подключены два резистора 3 и 4. Резистор 3 соединен с источником управл ющего напр жени 5, операционный усилитель 6 подключен к выходу делител .The controlled attenuator contains an L-shaped divider with a resistor, 1 in a serial branch and a field transistor 2 in a parallel branch, to the gate of which two resistors 3 and 4 are connected. Resistor 3 is connected to a source of control voltage 5, operational amplifier 6 is connected to exit divider.

Работает аттенюатор следующим образом ,.Attenuator works as follows,.

Claims

The signal from the input divider is fed to an operational amplifier 6, the output of which is directly connected to an inverting input. Since resistors 3 and 4 have the same resistance, half the voltage acts on the gate of transistor 2, which provides optimal conditions for balancing the characteristics relative to the origin. All control voltage from source 5 falls on resistors 3 and 4, so there are no voltage components in the output signal. Thus, in the described attenuator, the signal and control circuits are separated. Claims of the invention A controlled attenuator containing an L-shaped divider with a revistor in a serial branch and a field transistor. In the parallel branch, to the gate of which two resistors are connected, one of which is connected to the control voltage source, characterized in that, in order to reduce zero level mixing under the action of the control voltage, an operational amplifier is connected to the output of the divider, cixeMe included voltage repeater, the output of which is connected to the second resistor.