A digital power amplifier provides a direct conversion of a digital signal into the analogue domain where the signal has the capability to drive a high-power load such as a loudspeaker. Figure 1 shows the basic outline of such a system. The first stage performs interpolation of a Nyquist rate PCM (pulse coded modulation) signal to produce an oversampled PCM digital signal. This signal is then f...

This paper describes a low-complexity generic receiver for burst-mode continuous phase modulation. The burst consists of a continuous wave (CW) signal followed by a pseudorandom sequence and a data sequence modulated by continuous phase modulation (CPM). Joint coarse carrier frequency, phase and time synchronization is performed on the CW signal. Fine time synchronization is performed on the ps...

Copyright notification and enforcement, authentication, covert communication, and hybrid transmission are examples of emerging multimedia applications for digital watermarking methods, methods for embedding one signal (e.g., the digital watermark) within another “host” signal to form a third, “composite” signal. The embedding is designed to achieve efficient trade-offs among the three conflicti...

A statistical technique is presented for the characterization of spectral regrowth at the output of a nonlinear amplifier driven by a digitally modulated carrier in a digital radio system. The technique yields an analytical expression for the autocorrelation function of the output signal as a function of the statistics of the quadrature input signal transformed by a behavioral model of the ampl...

Based on the characteristics of time domain and frequency recognition theory, a scheme is designed to complete modulation identification communication signals including 16 analog digital modulations, involving 10 different eigenvalues in total. In in-class FSK signal, feature extraction carried out, statistical algorithm spectral peak number proposed. This paper presents method calculate rotati...

We introduce "the modulation cepstrum," a novel representation of an acoustic signal used to distinguish speech signal and environmental noises. The modulation cepstrum was computed by taking the inverse Fourier transform of the logarithmic modulation spectrum, a spectral representation of the temporal dynamics of a sub-band. We calculated the center of gravity of accumulated the modulation cep...

Step-Frequency signal is widely used in radar systems. However it suffers from the technique challenges that are the imaging moving-targets. In this paper, a new compound modulation signal is analyzed. It combines phased code modulation during the pulse and Step-Frequency modulation between the pulses time, and it is called as phase-coded StepFrequency signal. Numeric simulation comparison expe...

PSK is a common modulation format in digital communications. The estimation of modulation parameters is necessary for emitter interception in support of numerous military applications. This paper develops the Cramer-Rao Lower Bound for the modulation parameters of a PSK signal. The modulation parameters considered are the carrier frequency, the symbol time and the signal amplitude. The results ...