Analog predistorter with independently adjustable amplitude and phase suitable for SSPA

Abstract

The invention discloses an analog predistorter with independently adjustable amplitude and phase suitable for an SSPA. The analog predistorter is characterized in that an input signal is divided into two paths through a 3dB 90-degree bridge, and the two paths are output from a straight-through port and a coupling port respectively; the output of the straight-through port passes through a first blocking capacitor and then is loaded to a positive electrode of a first Schottky barrier diode and a negative electrode of a second Schottky barrier diode, and the positive electrode of the first Schottky barrier diode and the negative electrode of the second Schottky barrier diode are connected with a first direct current bias circuit; the output of the coupling port passes through a second blocking capacitor and then is loaded to a negative electrode of a variable capacitance diode, and a negative electrode of the variable capacitance diode is connected with a second direct current biasing circuit; and reflected signals generated by a nonlinear reflection branch and a linear reflection branch are synthesized and output at a 3dB 90-degree isolation port. According to the invention, two paths of asymmetric reflective structures are adopted, so that the adjustable parameters of the analog predistorter are more; the analog predistorter has the advantages that the amplitude and phase of a predistortion compensation curve can be independently adjusted, adjustability is high, and the structure is simple.

Description

technical field [0001] The invention relates to an independently adjustable analog predistorter suitable for SSPA. Background technique [0002] With the development of modern wireless communication technology, in order to cope with the rapid growth of the number of user terminals and communication data traffic, complex digital modulation schemes like quadrature amplitude modulation (64-QAM) and multi-carrier orthogonal frequency division multiplexing (OFDM) Transmission technology is widely used in modern wireless communication systems. The application of these technologies significantly improves the spectrum efficiency, but makes the transmission signal have a higher peak-to-average power ratio (Peak to Average Power Ratio, PAPR, hereinafter referred to as the peak-to-average ratio). The peak-to-average ratio signal is more likely to cause the power amplifier to enter the saturated working area, resulting in nonlinear distortion, which requires the power amplifier to have...

AI Technical Summary

Problems solved by technology

[0005] The currently applied analog predistorter has few adjustable parameters, and the circuit has poor adjustability

Moreover, the amplitude and phase distortion characteristics of the traditional predistorter are strongly correlated, changing any state of the circuit, the amplitude and phase characteristics will change

When the power amplifier is actually used, it is often difficult for the pre-distortion circuit to ensure that the amplitude and phase compensation meet the linearization requirements of the target power amplifier at the same time, resulting in poor linearization effect or even deterioration.

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