SU708505A1 - Pulse-code modulator - Google Patents

Description

one

The invention relates to the field of impulses. equipment and can be used in transmitting devices of radio engineering systems for various purposes.

Pulse modulators are known that contain a source of constant voltage, the output of which is bridged by a capacitive energy store, a switching element, an artificial forming line, an output pulse transformer with a load in the secondary winding circuit, a charging switch element, first and second trigger pulse generators, and outputs which are connected to the control electrodes of the switching element and the charging switching element, respectively, and the inputs are connected to the synchronizer, the signal sensor is oh soedinennsh the load 1.

The disadvantage of these modulators is the low pulse frequency of the modulator output pulses.

The closest in technical essence is a modulator containing a source of voltage with a capacitive energy store, a charged switching element, artificially forming a line, switching | {th element, two generators of trigger pulses controlled by a synchronizer, a load, is turned on the secondary circuit of the output pulse transformer, the primary circuit of which contains two followers, but the counter-I connected windings, between one of which and the anode of the switching element the choke is connected to syscheni 2.

The disadvantage of this modulator is that the frequency of the output pulses is not high enough.

The purpose of the present invention is to increase the frequency of the output pulses. To do this, in a well-known modulator containing a constant voltage source, the output of which is shunted by a capacitive energy collector, and its positive pole is connected to the anode of the charging switch element of the generator, which is controlled by the output of the first switching element. voltage through a series connected

an artificial forming line and the first primary winding of the output pulse transformer, in the secondary circuit of which the load is connected, and a sample signal sensor, and the second primary winding of which is connected between the first primary winding of this transformer and the anode of the switching element, the cathode of which is connected to the negative pole of the constant source voltage, and the control electrode with the output of the second generator of trigger pulses, the input of which is connected to the input of the first generator of trigger impulses pulses through the synchronizer, one of the outputs of which is connected to the sensor of the sample signal through the generator of control pulses, the primary windings of the output pulse transformer are switched on oppositely.

FIG. 1 shows a functional diagram of the proposed modulator; in fig. 2 - time diagrams illustrating his work.

A pulse code modulator contains a constant voltage source 1, a capacitive energy storage 2, a charging switching element 3, an artificial shaping line 4, a switching element 5, an output pulse transformer 6, the primary windings of the output pulse transformer 7 and 8, the secondary winding of the output pulse transformer 9, generator 0, 1 trigger pulses, load 12, sensor 13 of the signal of the sample, synchronizer 14, generator 15 of control pulses.

The modulator operates as follows.

The pulses (Fig. 2a) from the output of the generator 15 control pulses arrive at the input of the synchronizer 14. The synchronizer with these pulses alternately starts the generator 11 of the triggering pulses and the generator 10 of the triggering pulses, which, in turn, trigger the corresponding switching elements 5, 3.

Assume that at the initial moment the pulse from the output of the synchronizer 14 starts the trigger pulse generator 10, the output pulse of which (Fig. 2c) turns on the charging switching element 3 (time t,); Through the charging switching element 3, the primary winding 7 of the output pulse transformer 6 and the artificial forming line 4, the charge current of the latter starts to flow. At the same time, a pulse Uu is formed at the load 12 (Fig. 2g), and by the end of the process the artificial forming line is charged approximately to the voltage of the source of constant voltage Gfg. 2e).

After the termination of the charge of the line 4, which forms an artificial current through the charging switching element 3, it stops, for example (Fig. 2d) between the anode and the co

With the latter, it falls off and it turns off. It should be noted that at the moment when a current pulse flows through the charging switching element 3, the voltage between the anode and the cathode of the switching element 5 is zero, because in the second primary winding 8 of the output pulse transformer 6 an emf occurs the capacitors of the artificial line 4 and is directed opposite to this voltage. Consequently, the voltage Up 5 (Fig. 2d) at the anode of the switching element 5 appears only at the moment t, when the current of the charging switching element 3 stops. After the charging switching element is completely turned off, a triggering pulse can be applied on the switching element 5.

The next pulse from the output of the synchronizer 14 is fed to the input of the generator 11 triggering pulses, the output pulse of which (Fig. 26) at the time tj switches the switching element 5, begins the discharge of the artificial forming line 4 and the formation of a pulse on the load 12. At the time of the formation of this pulse also , as in the formation of the previous pulse, from the anode of the charge switching element 3

 the voltage is completely removed due to the EMF, which occurs in this case on the primary winding 7 of the output pulse transformer 6.

Thus, in a pulse-code modulator with its normal operation, it is fundamentally impossible such a moment when a complete anode voltage is simultaneously present on both switching elements, which eliminates the immediate breakdown of these switching elements.

In this case, it is meant that the ignition of any switching element occurs only after switching off the switching element, which is working at the previous moment. Since the turn-off time of, for example, thyratrons is in units of microseconds, the minimum interval between adjacent pulses will be equal to or somewhat larger than this value; In the lamp or transistor version of such a modulator, this time is much shorter and is determined by the time taken to eliminate breakdown in the load, since if the interval between adjacent pulses is comparable to this value, then simultaneous breakdown of both switching elements is possible. When working with an interval between adjacent pulses, close to the time of elimination of breakdowns in the load, a breakdown signal sensor 13 should be provided in the modulator, the output of which turns off the control pulse generator 15 or some other element of the modulator that prevents 3anycky - of the switching elements until the breakdown in the load is eliminated.

Claims (2)

1. USSR author's certificate N 272387, cl. H 03 K 3/53, 1968. 2. Authors certificate of the USSR ff 191631, cl. H 03 to 3/55, 1965 (prototype). T ist 1J .- ( t