SU54864A1 - Frequency doubler - Google Patents

Description

As is known, the coefficient of efficiency of a cascade, which operates in frequency doubling mode, in modern transmitting devices, fi other things equal to CONDITIONS, is significantly lower than the coefficient of efficiency of a cascade operating in amplification mode. In the same way, the maximum useful power, obtained by doubling, is much less than the power that the same stage would give when operating as an amplifier.

The accompanying drawing (Figs. 1 and 2) shows a scheme that eliminates the above disadvantages and brings the efficiency of the doubler to the efficiency of the amplifier.

In the proposed scheme, feedback on the second harmonic is applied. As a result, two voltages are applied to the grid of the lamp: 1) a stable exciting voltage of the first harmonic and 2) a reverse supply voltage of the second haomonic. Thus, the lamp simultaneously performs the functions of doubling and amplifying the doubled frequency. The latter allows unloading the lamps from the first harmonic by applying to the grid the minimum necessary voltage of this harmonic and loading it with the second harmonic.

All this leads to an increase in the maximum recoverable power and efficiency of the cascade and, consequently, to a decrease in the number of cascades of the transmitter.

FIG. 1 shows a circuit with inductive feedback; FIG. 2 with auto-transformer feedback.

A voltage from the stabilized master oscillator is applied to the doubler lamp grid through the coupling coil Ij. As a result of the amplification effect and multiplication in the oscillation mode of the second kind, an LC doubler tuned to the anode circuit is tuned to the second harmonic, some second harmonic voltage is released. A part of this voltage is fed back through the feedback jigger ij to the grid of the lamp and, adding to the voltage of the first harmonic, distorts the shape of the voltage on the grid. As a result, two pulses (of different magnitudes) of the anode current appear in the anode circuit of the lamp during the first harmonic period. Thanks

This will increase the component of the second harmonic of the anode current, which causes an increase in the voltage on the anode circuit and, consequently, an increase in the return nodache, etc., to the steady state resulting from the bending of the lamp characteristic.

The circuit is essentially regenerative. In the anode circuit, there is always a so-called. EHD, which is the result of a doubling of the supply of harmonic nerves.

Frequency of this. External emf equal to the natural frequency of the anode circuit. Therefore, the magnitude of the feedback can be taken both lower and higher than the critical one. In the first case, the circuit will not self-excite, but only increase the oscillations of the second harmonic. In the second case, nothing will change as compared with the first, since „external emf. suppress, due to the occurrence of seizure, the natural oscillations of the system, which could arise if there were no external conditions. or if its frequency was very different from the natural frequency of the anode circuit.

As the calculation of the proposed scheme showed, a doubler with feedback

gives the maximum useful power, determined by the well-known approximate formula for calculating the power for the amplifier:

f -}, -a

at a coefficient of useful action exceeding 70%.

The maximum recoverable power doubler without feedback is determined by the formula:

 / „E,

with a coefficient of useful action not exceeding 50-55%.

Thus, a feedback doubler yields a net power gain of 60% and a net efficiency gain of 15-20% compared with a doubler feedback.

The subject matter of the invention.

A frequency doubler whose oscillating circuit is connected to the anode circuit, tuned to the second harmonic of the grid excitation voltage, characterized in that a transformer or autotransformer fed by the second harmonic is used to perform feedback between the grid and the anode.

to the author's testimony of E. M. Manuk on

No. 54864

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