SU1231575A1 - High-frequency power amplifier - Google Patents

Abstract

The invention can be used in radio transmitters of the HF and VHF bands as an output power amplifier. The invention expands the bandwidth. The matching inputs of 5.8 input signal split into two antiphase signals of the push-pull cascade of transistors 1 and 2. The signal through the separation capacitors 4 and 7 is fed to the correction circuit CS 3 and 6, which equalize the gain in the frequency range. Ballast resistors 9 and 10 are used to equalize the input impedance of the amplifier and to ensure matching with the input source. Switching on capacitors 11 and 12 after resistors 9 and 10 reduces the capacitance values of capacitors II and 12 and reduces their parasitic inductance, which allows - to expand the bandwidth 1 sludge. e (L with txo3 you have eaten ch1 O1 jtq

Description

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The invention relates to radio engineering and can be used in radio transmitting devices KB and VHF-Diaphasers as an output power amplifier.

The purpose of the invention is bandwidth expansion.

Pa the drawing shows the electrical circuit diagram of a high frequency power amplifier.

The high-frequency power amplifier contains the first and second transistors 1 and 2, the first corrective CS circuit 3, the first coupling capacitor 4, the first matching transformer 5, the second corrective HC circuit 6, the second coupling capacitor 7, the second matching transformer 8, ballast resistors 9 and 10, the third and fourth separation capacitors 11 and 12.

High power amplifier works as follows.

The input signal using the first II of the second matching transformers 5 and 8, made on long lines, is divided into two anti-phase signals, providing the appropriate phasing of the push-pull stage on the first and second transistors 1 and 2. Signal through the first and second coupling capacitors 4 and 7 It is applied to the nerve and second correction KS circuits 3 and 6, which align the amplitudes of the two-stroke cascade in frequency and frequency. The signals then go to the bases of the first and second transistors 1 and 2. To align the input impedance of the amplifier in the frequency range and to ensure matching with the input source, ballast resistors 9 and 10 are used. The third and fourth splitter capacitors And 12 provide a permanent release. current. The inclusion of these capacitors after the ballast resistors 9 and 10 allows reducing the capacitance values of the third and fourth coupling capacitors 11 and 12 by more than an order of magnitude, since the input impedance of the arms of the push pull cascade on the first and second transistors 1 and 2 is on low frequencies shunt effect of ballast resistors 9 and 0)

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is made by resistance of the nerve and second corrective KS circuits 3 and 6, which is more than an order of magnitude greater than the resistance of the ballast resistors 9 and 10 which allows the bandwidth of the high frequency power amplifier to be expanded.

The use of two power sources in the power amplifier amplifier makes it possible to increase the stability of the parameters of the amplifier and also, due to better symmetry, to reduce the requirements for filter capacitors in the power amplifier power supply circuits.

Claims (1)

The invention includes a high-frequency power amplifier containing first and second transistors connected in series through a common collector and a common emitter according to the power supply circuit, respectively, the base of the first transistor connected in series to the first correction KS circuit and the first coupling capacitor to the first output of the first winding matching transformer, and the base of the second transistor through a serially connected second correction KS circuit and the second separating condensate - to the first output of the first winding of the second matching transformer, while the corresponding ballast resistors are included between the first leads of the first and the second windings of the first and second transformers, the second lead of the second winding of the second matching transformer is connected to the common busbar the fact that, in order to expand the bandwidth, between the emitter of the first transistor and the first output of the second winding of the first matching transformer VC The third coupling capacitor is connected, the fourth 5th coupling capacitor is connected between the emitter of the second transistor and the first output of the second winding of the second matching transformer, the second outputs of the first windings of the first and second transactivating transistors 312315754 formers are interconnected, the matching transformer is the second output of the second winding, first with the input of the power amplifier.