SU45321A1 - Device for neutralizing the cascade of powerful amplification - Google Patents

Description

The present invention relates to a device for neutralizing a power amplification cascade.

The invention consists in the fact that in order to obtain the independence of the balance of the bridge from the setting of the communication coil, the cascades are connected between the grid and one of the points of the anode circuit.

In FIG. 1 shows a circuit diagram of a high-frequency amplification cascade neutralized by the proposed method; FIG. 7.- The equivalent circuit developed in the form of a bridge of FIG. one.

 As can be seen from the diagram shown in FIG. 1, the coupling coil of the amplification stage grid with the anode circuit of the previous stage is not connected in the usual way, but between the grid and a point on the anode circuit coil. The point of attachment of the contact of the wire coil divides the anode coil into two parts ii and isi whose ratio in the neutralization process is equal to the ratio of the intra-tube capacitances and С ".

- As can be seen from the diagram of FIG. 2, if you select 1 and L.- ,, i.e., the points of the t: on the eDonent of the net contact will be absent directly

caskYes in the anodna contour of the next, in the same way

there will be no reverse response of the booster to the pathogen.

FIG. 2 letters L, L and Z. denote self-induction of inputs-anode, grid and heat.

For a variable anode voltage of the grid-to-filament point between the anode and the filament, the filament of the lamp is not equipotential, however, the self-excitation of the cascade is impossible. u |

Indeed, the condition for the balance of the bridge is (Ii + i) C

 (2) (.- "equality shows that for the frequency at which neutralization was carried out, connected between the anode and the net and the thread, the circuits are tuned to resonance, t, both are purely watt. For a whole other frequency, the excitation is also impossible, because these contours will be built in one direction, i.e., they will be reactive impedances of the same sign.

FIG. 2 self-induction inputs Z., 1 „and L

enter, respectively, in the direction from LI, Z.2 and to the diagonal with the communication coil, i.e. fundamentally nothing can change except the connection point of the tact of the communication coil on the anode carcass.

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Setting the anode circuit -z case -.kv. It is undesirable to produce a parallel-capacitive variable capacitor, since this will lower the p anode circuit. The use of the usual for uskv. A circuit with a series capacitor coil will cause the bridge balance to depend on frequency. It is most convenient to adjust the anode circuit by means of an anode coil connected parallel to the circuit consisting of a variable capacitor and a self-induction coil connected in series, with self-induction prevailing in the circuit. Such a vHe tuning system will cause the balance of the bridge to depend on the frequency, will not reduce the p anode circuit and is as convenient as tuning by the parallel coil of the condenser.

It has been noted above that for the anode oscillatory voltage of a point, a thread is not equipotential. Ego means that the part of the anodic alternating voltage, which determines the ratio C and C,

act on the grid of the lamp. Thus, the voltage on the grid of the amplifying lamp will be equal to the difference between the voltage and voltage of the response from the exciter and the response voltage, i.e. the part of the voltage supplied to the network from the exciter will be destroyed by the voltage of the feedback.

However, due to the condition of the bridge balance

It can be seen that the contour 4 i “Se n. E.D.S.

. UI / 1 is tuned to a voltage resonance, somewhat confused by the presence of Z, J, and L ,. Selection of value

hC, which should be made variable, can be arbitrarily close to the resonance, i.e., it is easy to obtain the required large voltage on the grid. .

Another consequence of the presence of a backward response to the grid of the amplifying lamp is a smaller, than usual, recess of modulation in the mode with an angle of 90 °. ..,

The advantages of the gain of the proposed scheme compared with the schemes of anodic neutralization and two-stroke neutralization, not to say that it is impossible to obtain for the latter with us. good and frequency independent neutralization is a small loop capacitance and a small amount of required Z.

This situation will significantly improve the efficiency. cascade and reduce the number of installed lamps. For b-8m waves and available types of lamps, the application of the proposed Scheme will reduce the number of lamps by half.

The subject matter of the invention.

A device for neutralizing a power amplifier stage, characterized in that the coil of the connection of the grid of the cascade with the anode circuit of the previous cascade is connected between the grid and one of the points of the coil of the anode circuit of this cascade to obtain an independent balance of the bridge from the setting for which the anode coil is connected a circuit consisting of a capacitor of variable effector and kafush of self-induction connected in series. /