Drift Correction Modulation scheme for digital signal processing

The article describes a new method of embedding and extracting the digital watermark in an acoustic signal, which operates in the frequency domain and uses a drift correction modulator of the watermark’s phase angle, as well as a precise correction procedure of the watermark signal to the minimum masking threshold. The Drift Correction Modulation (DCM) has been worked out for the needs of the watermarking system with a large data payload and robustness against degrading factors which occur during signal processing. The digital watermark embedded in the original signal using the DCM method is inaudible and robust against the majority of degrading factors. The DCM method may be used in Digital Signal Processing applications, e.g. for a hidden authentication of subscribers in telecommunication channels or for determining the output phase mistuning of devices. DCM is characterized by a high normalized data payload of the watermark signal and may be implemented in applications of hidden and secure data transmission. The paper presents the results of auditory tests according to the ITU-R 1116-1 standard; moreover, results of the watermark extraction tests in a VHF radio link, with the use of military tactical radio stations have been presented.