SU492034A1 - Pulse shaper - Google Patents

Description

In the initial state, transistor 1 is open, and transistors 7 and 12 are closed.

Thus, before the signal arrives at the input of the pulse generator at the collectors of transistors 1 and 7 (output 16), a potential close to zero operates, which is repeated at the emitter of transistor 12 (output 17) operating in the emitter follower mode. A series of diodes 10 and 11 connects zero potentials. Consequently, the same potential acts at the junction point of the diodes mentioned (output 18). The voltages on capacitors 2 and 13 are zero.

The input signal of negative polarity (difference to zero) is simultaneously supplied to the inputs of the transistor switches (1 and 7). The transistor 7 opens abruptly to form a steep front of a positive polarity pulse at the output 16 of the pulse shaper. The diode 10 is shifted in the opposite direction, and therefore, the positive potential from the collector of transistor 7 to the output 18 is not received.

At the same time, the input signal closes the transistor 1. The capacitance of the capacitor 2 is charged to the voltage + E according to a linear law, since the capacitance charge current is controlled by a constant-current source of adjustable magnitude 3. The voltage on the capacitor 2 is repeated at the output of the transistor 12 emitter follower. The steepness of the pulse front formed on the collector of transistor 1 depends on the capacitance capacitance 2 and the charge current of this capacitance, the change of which is provided in the device.

Thus, the duration of the rise time of the pulses at the output 17 (emitter of the transistor 12) is regulated in two ways, which provides a wide range of adjustment of this parameter (from tens of nanoseconds to seconds), and the nonlinearity of the pulse front does not exceed 5%. Through a directly mixed diode 11, the capacitance of the capacitor 13 is also charged to the voltage - | -, and the steepness of the voltage rise is determined by the pulse front, which is formed on the collector of the transistor 1 and is repeated at the output of the transistor 12 of the emitter follower. Consequently, the duration of the rise time of the pulses at the output (the midpoint of the series-connected diodes 10 and 11) is also regulated, and the nonlinearity of the front of the output signal does not exceed 5%. During the entire length of time from the beginning of the formation of the pulse front at the outputs 16, 17, 18 to the beginning of the formation of their decay, the diode 10 is shifted in the opposite direction.

At the end of the pulse at the output of the pulse driver, transistor 1 opens abruptly, capacitor 2 discharges, through an open transistor, to form a steep drop in pulse at the collector of transistor I, and hence at the output 17 of this device. The diode I is shifted in the opposite direction, which prevents the discharge of the capacitor 13 through the resistance of the resistor 14.

At the same time, the transistor 7 is locked, and the diode 10 is shifted in the forward direction. The voltage on the capacitor 13 decreases from - (- E to zero linearly, as its discharge circuit passes through the diode 10 and the source 9 of the direct current to the common bus.

The steepness of the pulse decay depends on the capacitance of the capacitor 13 and the discharge current of this capacitor. This device provides the ability to change these parameters.

Thus, the duration of the decay time of the pulses at the outputs 16 and 18 of the pulse shaper is controlled in two ways, which provides a wide range of adjustment for this parameter (from tens of nanoseconds to seconds), with a non-linearity of decay not exceeding 5%. Moreover, as follows from the principle of operation of the described device, the duration of the fall-off time of the pulses at the output 18 is adjusted independently of the changes in the duration of their rise.

Essentially, this pulse shaper is a universal device capable of performing the following functions:

the formation of pulses with a small value of the duration of the rise time and adjustable slope (output 16).

pulse shaping with adjustable rise time and steep

recession (exit 17).

the formation of pulses with independent adjustment of the duration of the rise and fall times (exit 18).

In all three cases, it is provided:

high voltage utilization ratio (1).

Low coefficient of nonlinearity of the front and the decay of pulses (5%).

The duration of the output signal equal to the duration of the pulse at the input

() A wide range of independent adjustment of the durations of the rise and fall times of the pulses on the outputs of the impulL1) COM.

Formula 3 and b: e te e and u

A pulse shaper containing two keys with a common output on transistors, between the collector and the emitter of one of which a storage capacitor is switched on, constant-current sources of variable size in the collector circuits of key transistors, characterized in that in order to obtain an independent adjustment of the duration of the fronts and increase control range, an emitter follower and an additional capacitor are inserted in it, one lining of which is connected to the common bus and the other to the midpoint in series

connected diodes, the cathode of one of which is connected to the collector of the transistor of the first key, and the anode of the other - to the output of the emitter follower.

+ E

+ E

-f