SU373886A1 - SUPREGENERATIVE DC AMPLIFIER - Google Patents

Description

I

The proposed superregenerative DC amplifier can be used in electronic devices, in particular, to amplify and measure small emfs, to convert the DC voltage to alternating, as a potential null-organ, phase zero-organ, sensitive phase discriminator and synchronous detector.

Known superregenerative. DC amplifiers containing triggers with pulsed power. In prior art DC amplifiers, a positive feedback circuit is used to increase the gain factor, which is periodically closed and opened with keys.

However, such circuits have low speed, and mechanical contacts are used as keys. When using electronic switches, the amplifiers have significant drift and low sensitivity, depending on the corresponding key parameters.

In order to increase speed while maintaining a sufficiently small drift and to obtain a linear dependence of the amplitude of the output pulses on the level of the input signal in the proposed device between

The bases of the transistors of the trigger include a capacitor, the covers of which, through resistors, are connected to the input voltages.

The drawing is a diagram of the proposed super-regenerative logg amplifier of another current.

The proposed amplifier is designed as a symmetric trigger, power supply. to which is fed from a pulsed generator. ora /. Tpis generator consists of a transistor 3 type ppr, their collector loads 4 and 5, potential connections 6-9, forming a positive feedback loop, input resistors 10 and //,: on the source; signals, capacitor 12 and a balancing resistor 13.

Terminals M and 15 are input, and terminal blocks 16 and 17 are output.

At the moment prior to the supply of a negative supply pulse, there are no currents and voltages in the circuit, with the exception of voltages and currents due to the increased emf. The latter charges the capacitor 12 to a certain amount EO.

At the first moment after the negative supply pulse is lost from the pulse generator /, the collectors and bases of transistors 2 and 3 produce voltage and currents

identical in both transistors and ensuring their work in the active mode due to the inclusion of a capacitor 12 between the bases of the transistors.

Moreover, while the capacitor cannot instantaneously change the charge, then the potentials on the bases differ by the magnitude of EO, as a result, as a result of positive feedback, the asymmetry from the asymmetry increases. At the end of the supply pulse, the capacitor is charged from a certain time constant until the voltage is about, and the circuit returns to its original state.

The DC amplifier produces pulses, the leading edge of which increases, and the rear one drops off along the exponentials. Their repetition frequency is equal to the frequency of the power supply pulses. Amplitude depends on e.a. linearly. The gain is governed by the ratio of the duration of the power supply impulse to a constant time, depending on the circuit parameters and the size of the capacitor 12.

Thus, the speed of the dc amplifier is determined by the maximum amplification frequency of the selected transistors, the zero drift is absent, because at the time preceding the lithium pulse, the circuit is de-energized and the instability of the circuit is not affected by the amplifier; voltage from the input voltage level.

Subject invention

Superregenerative DC amplifier containing a trigger with pulsed power supply, characterized in that, in order to simultaneously achieve high speed, minimum drift and linear dependence of the amplitude of the output pulses on the input signal level, a capacitor is switched on between the bases of the transistor trigger and connected to the input bus.

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