Adaptive carrier and symbol joint synchronization method of QPSK signal

Abstract

The invention provides an adaptive carrier and symbol joint synchronization method of a QPSK signal. The method comprises the following steps: determining an input signal, obtaining two paths of QPSKbaseband signals which are orthogonal to each other, calculating a carrier phase error signal and a timing phase error signal of the baseband signals by using a phase discriminator and a Gardner timing error detector respectively, calculating a characteristic value, and dividing a synchronization process into three stages. In a coarse synchronization stage, a transition stage and a fine synchronization stage, corresponding loop filters are identified and selected in the existing synchronization stage, signals are corrected, and final judgment signals are output. According to the method, the two technical indexes of the synchronization speed and the synchronization precision of the synchronization loop can be effectively improved at the same time, and particularly, the synchronization effect of the QPSK signal with large deviation is obviously improved.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, is specifically applied in a digital receiver, and in particular relates to an adaptive carrier and symbol joint synchronization method of a quadrature phase shift keying (the Quadrature Phase Shift Keying, QPSK) signal. Background technique [0002] Carrier synchronization and symbol synchronization in digital receivers were proposed in the 1980s. In 2014, Hua Jie from the University of Science and Technology of China and his research team organically combined the classic Costas carrier synchronization loop and the Gardner symbol synchronization loop to form a joint synchronization loop. The proposed joint synchronization loop is divided into two parts: Costas carrier synchronization and Gardner symbol synchronization. The signal processing flow is as follows: the digital intermediate frequency signal first enters the Costas carrier synchronization loop, the output of the pulse s...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the single loop parameter setting of the existing joint synchronization method, especially for the problem that the QPSK signal with a large deviation cannot take into account the synchronization speed and synchronization accuracy, and proposes an adaptive carrier of the QPSK signal and Symbolic Union Synchronization Method

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