A RF Watermark Embedding and Extraction Method for CPM Signals

Abstract

The invention discloses a radio frequency watermark embedding and extracting method for CPM signal, and belongs to the field of radio frequency watermarks; the method comprises the steps of using a CPM baseband signal as a carrier signal, superimposing a watermark signal on the phase of the carrier signal according to the watermark embedding ratio so as to obtain a baseband signal, and modulatingthe baseband signal to a carrier frequency to form a CPM radio frequency signal; reducing the carrier frequency of the CPM radio frequency signal to a zero intermediate frequency, so as to obtain a baseband signal; demodulating the baseband signal, reconstructing the carrier signal phase after the carrier code element is obtained, carrying out phase unfolding on the baseband signal to obtain a signal phase, removing the reconstructed carrier signal phase from the signal phase, and obtaining a watermark signal; carrying out polar detection on the watermark signal, and demodulating the bit information contained in the watermark signal. According to the method in the invention, when the watermark bit is switched, the phase continuity of the signal is not damaged; and the system performance isguaranteed to be unchanged.

Description

technical field [0001] The invention belongs to the field of radio frequency watermarks, and more specifically relates to a method for embedding and extracting radio frequency watermarks oriented to CPM signals. Background technique [0002] Information hiding technology represented by digital watermarking technology has been greatly developed, and with the enhancement of computer performance, it is necessary to develop new information hiding technology. As a new information hiding method, radio frequency watermarking technology increases the diversity of information hiding methods. Traditional digital watermarking technology mainly uses multimedia signals as information carriers, and cannot be applied to lower-level physical signals; radio frequency watermarking introduces watermarking technology into radio frequency communication signals. [0003] The CPM signal is a continuous phase modulation signal. This modulation method is characterized by continuous phase and consta...

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Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a CPM signal-oriented radio frequency watermark embedding and extraction method, thereby solving the existing problem in the prior art that the continuity of the signal phase is destroyed after the watermark is embedded, resulting in a decrease in system performance. technical problem

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