SU78485A1 - Radio transmitter - Google Patents

Description

The object of the present invention is a radio transmission device with an improved k. There are two amplification channels, the output lamps of which are loaded on two oscillatory circuits, one of the oscillatory coding is connected between the anodes of the lamps, and the second between the connection point of the cathodes of the lamps and the midpoint on the primary circuit.

Radio transmitter circuits in which the resistance of the primary circuit (between the anodes of the lamps) is 4 times the resistance of the secondary circuit (connected between the cathode and the midpoint of the primary circuit) is known. When modulating oscillations in the primary circuit in a positive system, oscillations in the secondary circuit are modulated in a negative system; contours are associated with separate directional antennas with non-overlapping radiation patterns for simultaneous transmission (negative and positive) in two different directions.

In order to carry out modulation in existing circuits, dephasing of the excitation voltage of the lamps of the amplification channels is used. In contrast, the present invention proposes to excite a lamp of one channel with an unmodulated voltage of a carrier frequency and a lamp of a second | Channel-voltage of side frequencies, which is new and gives the possibility of obtaining a high efficiency of the transmitter at small non-linear distortion x.

The accompanying drawing shows schematic diagrams: an output stage (Fig. I), an output stage for short waves (Fig. 2), the same for long waves (Fig. 3), an excitation stage (Fig. 4) and a modulated cascade (Fig. 4). five).

In the output stage of the proposed transmitter (Fig. 1), the operation is carried out as follows. Here, both K and Kz circuits are tuned to the carrier frequency. The lamp L is excited by a constant amplitude of the voltage carrier voltage. Usin t, the lamp is excited by the sum of the voltages of the two side frequencies f / sinu t McosSi. The resonant resistance of the circuit is 4 times greater than the resonant resistance of the circuit K, 2- The total resonant resistance is adjusted so that lamp L operates in a critical mode. The high efficiency of the circuit is ensured by the fact that lamp i at any time of modulation operates in a critical mode, i.e. under the conditions of maximum efficiency, Lam 351

At 100% modulation, it has a sufficiently high efficiency. With decreasing modulation, the efficiency decreases, but at the same time the power consumed by the lamp Lg decreases. The overall efficiency of the circuit therefore remains rather high and amounts to 90-100% (depending on the modulation depth) of the efficiency of the critical mode.

The lamps are of the same type, each with a rated power of the appropriate transmitter power in telephone mode.

At the memorial power, the proposed scheme is twice as profitable as grid and anode modulation schemes. The proposed scheme has the advantage that, unlike all other schemes with a high efficiency, it has small non-linear distortions.

For short wavelengths, the circuit shown in FIG. 2. This scheme provides the possibility of applying neutralization.

A feature of the proposed output circuit of a radio transmitter is that power is released in two circuits. Power directly add difficult, since they are modulated in antiphase at a low frequency. Offering power from two circuits to two multi-directional antennas A and A, which is now practiced on short waves, is proposed.

At long wavelengths, the radio transmitter circuit shown in FIG. 3, in which power in one circuit is rectified and used for an anode modulus. In this case, it is possible to joint

cascade operation on one antenna. In this case, the modulation transformer is obtained at a nominal power 3 times less than with anodic modulation of the transmitter of the same power. In this case, the efficiency is not lower than with anodic modulation.

Excitation at the output stage grid can be removed from the anodes of the corresponding lamps of the previous stage, assembled according to a similar scheme (Fig. 4). With this method of excitation, the necessary excitation voltage phasing is automatically obtained.

The modulated cascade of the radio transmitter is assembled according to the scheme of FIG. 5 and, as can be seen from it, also serves to provide the correct phase shaker. This circuit represents a balance modulator with two circuits in the anode circuit, one of which separates the carrier voltage, the other the sum of the side frequencies UiS, Msin2. This greatly facilitates the operation of the lamps.

Subject invention

A radio transmitter having two amplification channels and two load circuits, connected anode values of transmitter channel channels — one between the anodes of these lamps, and the second between the connection point of the cathodes of the lamps and the midpoint of the primary circuit, characterized by the fact that one of the channels of the aerial transmitter is given voltage carrier frequency, and the second side voltage-frequency.