ПОСТРОЕНИЕ МОЩНЫХ ШИРОКОПОЛОСНЫХ УСИЛИТЕЛЕЙ ПОСТОЯННОГО ТОКА МОДУЛЯЦИОННОГО ТРАКТА ПЕРЕДАТЧИКОВ С РАЗДЕЛЬНЫМ УСИЛЕНИЕМ СОСТАВЛЯЮЩИХ

Abstract

Increasing transmission path efficiency, as the largest consumer of electricity, is relevant for any wireless communication devices, digital television, and radio broadcasting. A number of methods are used to improve efficiency, including Envelope Tracking (ET) and Envelope Elimination and Restoration (EER, or Kahn method). Increasing the bandwidth of used frequencies in 5G radio systems requires expanding the modulation path DC amplifiers bandwidth to 250…500 MHz or more. The possibility of using amplifiers with input signal quantization (AISQ) as an alternative to the most common broadband hybrid modulators combining linear and switching (with PWM) amplification channels is considered. It is shown that in order to obtain AISQ high energy characteristics, it is advisable to perform, according to the scheme with output channels parallel connection, the switching of the amplifying cells along the input circuits and to reduce the saturation voltage on the output transistors. An approach has been developed for the AISQ characteristics optimizing according to the criterion of minimum losses. The example of AISQ parameters optimization and its energy characteristics calculation for a linearly increasing signal showed that, compared with a class B amplifier (n = 1), already with three-level quantization, the loss power in the AISQ decreases by 2...2.5 times (depending on the residual transistor voltage). A further increase in n leads to a less sharp decrease in the relative loss power, which, with the obvious complication of the circuitry implementation of such AISQ, makes the use of three-four-level quantization the most expedient. With these parameters, the AISQ becomes competitive with hybrid modulators and does not create electromagnetic interference from the PWM path.