Coherent demodulation of digitally modulated signal having continuous phase and constant envelope

Abstract

Abstract PURPOSE: To provide synchronization that enables coherent demodulation of an optional kind of modulation by approximately detecting frame synchronization and bit synchronization and performing progressive improvement of an approximate value by a loop that is inserted between a low loop and a fast loop. CONSTITUTION: Each packet gives a known reference signal of N bits, makes frame synchronization and bit synchronization to be approximately detected by the correlation of differential phase, and also includes a preamble string that starts to evaluate parameters of initial phase θ0 and residual frequency offset Δf0 , And the progressive improvement of an approximate value is performed by a loop that is inserted between a low loop which is operated when a threshold for bit synchronization detection is exceeded and a fast loop which intermediately decides bits of an additional block for evaluation of the θ0 and Δf0 . The detection of frame synchronization and bit synchronization is acquired by the 1st correlation in differential phase in which the transmission point of a packet is acquired with ±T/4 with T as a duration time of one bit and the 2nd correlation in differential phase which is performed by a reference signal that is shifted by T/4.

Inventors

• 👤 Benoit Gelin
• 👤 ブノイ　ゲラン
• 👤 Michel Lebourg
• 👤 ミシェル　ルブール

Bibliographic Details