SU1518870A1 - Amplitude detector - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to increase the sensitivity. The amplitude detector contains transistors (T) 1-8, G-ry 9-12 current, resistors 13 and 14 and sources 15 and 16 constant voltage. When a negative voltage is applied to the base T 5, it is emitted at the emitters T 1, 2 and 7, which leads to a redistribution of the currents of the G-9, 10 and 11. The currents T 2, 3 and 5 are reduced, and T 1, 4 and 6 increase. In this case, the sum of the currents flowing through the emitter junctions of the pairs T 5 and 1 and T 2 and 6 remains constant. This ensures an almost constant voltage drop at the two emitter-base junctions of these T. The voltage drop at the emitter junction T 1 and 2 is compensated for by the voltage drop on the two emitter junction T 7 and 8 set by the current generator 12 current. The goal is achieved through positive feedback acting through T 3 and 4, which serve as a differential current cascade for T 1 and 2. 1 sludge.

Description

The invention relates to p;) di (technology and can be used in amplitude detectors.

The purpose of the invention is to increase the sensitivity.

The drawing shows a structural electrical circuit of an amplitude detector.

The amplitude detector contains from the first to the eighth transistors 1–8, the first to the fourth generators 9–12, the first and second resistors 13 and 14, and the first and second sources 15 and 16 of constant voltage.

Amplitude detector works as follows.

An input para-phase signal is supplied to the bases of the fifth and sixth transistors 5 and 6. Currents one through four of the current generators 9-12 are set in the ratio of 3: 2: 2: 1.

In the absence of an input signal, the current of the first generator 9 of the current is divided into three equal parts flowing through the emitter transitions of the transistors of the first, second and seventh, eighth 1, 2 and 7, 8, current of the second generator

The 10 current is divided into two equal parts flowing through the emitter junctions of the fourth and fifth transistors 4 and 5, the current of the third current generator II is divided into two equal parts flowing through the emitter junctions of the third and sixth transistor 3 and 6, the fourth current generator 12 current flows through the emitter junctions of the seventh and eighth transistors 7 and 8 (hereinafter, there is no distinction between the KOJineKTopa current and the emitter current, since a high value of the transistor transfer coefficient is assumed) over current.

When a negative voltage is applied to the base of a pth transistor 5 (at zero voltage at the base of the sixth transistor 6), this voltage is offset at the emitters of the first, second and seventh emitters at the emitter-base junctions of the first and fifth transistors 1 and 5 transistors I, 2 and 7, which leads to the redistribution of currents of the first, second and third current generators 9-11. The currents of the second, third, and pth transistors 2, 3, and 5 decrease, while the first, fourth, and luecToro transistors 1, 4, and 6 increase, with

This sum of the currents flowing through the emitter junctions of the pairs of the fifth and first transistors 5 and I and the second and sixth transistors 2 and 6 is kept Fifth, which ensures a nearly constant voltage drop across the two emitter-base junctions of these transistors. For example, the following currents can be set (the unit takes the value of the currents in the initial state): through the second, third and fifth transistors 2, 3 and 5 - zero, through the first,

The fourth and sixth transistors 1, 4 and 6 are two. The third and fourth transistors 3 and 4 serve as a differential current stage for the first and second transistors 1 and 2.

The resistance values of the first and second resistors 13 and 14 are chosen at the level of ten ohms, which ensures the broadband nature of this device,

The voltage drop at the emitter junctions of the first and second transistors 1 and 2 is compensated by the voltage drop across the two emitter junctions of the transistors 7 and 8, set by

current of the fourth generator 12 current.

Due to the positive feedback acting through the third and fourth transistors 3 and 4, the sensitivity of the amplitude detector

units of millivolts with high linearity of the transfer characteristic.

Claims (1)

Invention Formula Amplitude detector containing the first and second transistors, the emitters of which are interconnected and connected to the first output of the first the current generator, the second output of which is connected to the common bus, the third and fourth transistors, the emitters of which are connected respectively to the collectors of the first and second transistors, fifth and sixth transistors, base which are respectively the first and second inputs of the amplitude detector, the collectors are connected to the output of the first constant voltage source, and the emitters to the first terminals of the second and third current generators and bases of the first and second transistors, respectively, the fourth current generator, the first output of which 515188706 Rigo is connected to the output of the first IS-resistors, the base is connected to the output of the second constant voltage source, constant voltage source, and the first and second resistors, the first terminals - to the bases, respectively which are connected to the output of the first and first transistors, the emitter of constant voltage, the tertiary of the seventh transistor is connected serially connected in diode with the first output of the first generator switching on the seventh transistor and the eighth current, and the collector of the eighth transistor, the collector of which is led - with the second output of the fourth The output of the amplitude detector, the Q current generator, while the type is provokingly distinguished by the fact that, in the third and fourth transitivity of the sensitivity, the tori are opposite to the type of the third and fourth transmitters of the first, second, fifth, The sides are connected to the second terminals of the sixth, seventh, and eighth trans-according to the first and second | 5tor.