SU416828A1 - - Google Patents

Description

one

The invention relates to the pulse technique and can be used in radar and remote control systems.

The known multiphase multivibrator with pulsed bridge delay elements, containing diodes, the cascades of pulse bridge delay elements being connected to each other through single-stage transistor amplifiers assembled according to a common emitter circuit, has a low noise immunity.

The purpose of the invention is to improve the noise immunity of the multivibrator.

For this, the collectors of several output transistors are connected via diodes to the bases of the transistors.

The drawing shows the principle electrical circuit of the proposed multivibrator consisting of five stages.

The operation of a multivibrator containing more cascades is similar.

The multivibrator contains diodes 1, 2, and 3, cascades of pulsed bridge delay elements 4–8, which are connected 1 between themselves through single-stage amplifiers on transistors 9–13, assembled according to a common emitter circuit. The collectors of one or several transistors are connected via diodes to the base: the remaining transistors (in the circuit, the collector of transistor 12 is connected via diodes 1, 2, and 3 to the bases of transistors 9, 10, and 11).

Multivibrator works as follows.

When connected to a power source, the pulse bridge elements 4-8 are charged. Charging currents cause transistors 9–13 to open. When unlocking the restoring transistor 12, the diodes open.

1, 2 and 3, since the potential of their cathodes relative to the earth decreases to almost zero. In this case, transistors 9, 10, and 11, to the bases of which diodes 1, 2, and 3 are connected, are locked because the potentials of their bases are fixed at the level of ground potential. Element 8, following the restoring transistor 12, is completely disconnected through the open transistor 12, and the transistor 13 is then locked.

Since diodes 1, 2 and 3 are connected to the bases of all transistors, except for the base of the restoring transistor 12 and the transistor 13 that follows, the total number of diodes is two less than transistors.

The time interval during which the restoring transistor 12 is open is determined by the parameters of the element 7 turned on at its input. The transistor selects the transistor at the output of which the impulse bridge element is turned on with a maximum time delay, so that during the time during which transistor 12 is open, there is a positive charge of elements 4-7, except for element 8 discharged through an open transistor 12 The transistor 12 is locked at the moment of equilibrium of the element 7 turned on at its input, since at this moment the charge current of the element 7 sharply decreases to zero. When the transistor 1.2 is locked, diodes I, 2, and 3 are locked, as the potential of their cathodes increases to the value of the voltage of the power source, and therefore, they have no further effect on the operation of the circuit until the beginning of the next time.

If a random amplitude is influenced by a sufficiently large amplitude, the normal operation may be disturbed and iMoryT opens several stages, but 1When it turns out, the rest of the transistors are locked by means of the transistor, diodes 1, 2 and 3. After this, the normal operation of the circuit restored.

In some cases, for example, by constant action of a regular impulse noise, to completely exclude the possibility of circuit failure, it is necessary to connect the collector of each (and not just one) transistor through diodes to the bases of the remaining transistors. Resistors. In this case, the number of diodes for an n-cascade multivibrator will be n (n - 2).

Subject invention

Multiphase multivibrator with impulse bridge delay elements containing diodes, the cascades of impulse bridge delay elements being connected to each other through single-stage transistor amplifiers assembled according to a common emitter circuit, characterized in that, in order to improve noise immunity, several output collectors transistors are connected via diodes to the input bases.