A Pre-Correction Algorithm for Broadcasting Transmitter

Abstract

In a terrestrial broadcasting system, a power amplifier (PA) and mask filter (MF) are utilized to extend the service area of the broadcasting network, while suppressing unwanted out-of-band emissions. However, due to analog circuit imperfection, these devices inevitably cause significant linear and nonlinear distortions which may lead to spectral re-growth and the degradation of signal-to-noise ratio (SNR) performance. In order to compensate for these distortions, an adaptive pre-correction algorithm is proposed in this paper. Unlike conventional techniques, the proposed algorithm iteratively estimates the linear and nonlinear distortions using selective feedback loops. Computer simulations and laboratory prototype test results demonstrate that the proposed algorithm provides nearly an spectral gain of 8 dB near the edge of the channel bandwidth and an SNR improvement of 20 dB. Thus, it efficiently improves the dynamic range of the PA and MF.