Method for detecting and correcting clock error lock of CPM signal greater than 1 modulation index

Abstract

The invention discloses a method for detecting and correcting a clock error lock of a CPM signal greater than 1 modulation index. When the modulation index of the CPM signal is a half integer greaterthan 1, a signal has a plurality of positive slope zero-crossing points in half of code element time through an S curve of the delay locking ring; mistaken locking of the delay locking ring is caused.An error detection decision device is introduced to detect whether the tracking ring is locked mistakenly. When error lock occurs, the output of an error accumulator in the error detection decision device can exceed a set threshold. A judgment is made that the delay locked loop has error locking. The delay to a correct locking interval is pushed through an error detector and the value of an erroraccumulator is reset to be 0 under the condition of setting an appropriate threshold value, an appropriate weighting coefficient and an appropriate propelling interval, and the tracking loop enters acorrect tracking process. Through verification on a Matlab platform, under the condition of different modulation indexes, the error detection decision device can correctly judge the false lock and enable the delay locking ring to enter a correct locking interval again.

Description

technical field [0001] The invention belongs to the field of digital communication, and specifically relates to solving the wrong locking problem caused when a CPM signal with a modulation index greater than 1 passes through the S-curve of a delay-locked loop and has multiple zero-crossing points with a positive slope within half a symbol. Background technique [0002] Continuous Phase Modulation (CPM) is highly regarded for its bandwidth efficiency and constant RF envelope. This type of modulation signal is especially attractive in radio channels with nonlinear amplifiers because it allows us to fully utilize the amplifier power. Although the CPM signal has many advantages, the resulting problems are the high complexity of the receiver and the difficulty of synchronization. [0003] Synchronization is an important practical issue in both digital communication systems and analog communication systems employing coherent demodulation. Since the receiving and receiving ends a...

AI Technical Summary

Problems solved by technology

Although the CPM signal has many advantages, the resulting problems are the high complexity of the receiver and the difficulty of synchronization

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