Signal original form to a waveform expressed as a current ("I") or a voltage ("V"), or an electromagnetic waveform, for example, an optical signal or radio transmission. Once expressed as an electronic signal, the signal is available for further processing by electrical devices such as electronic amplifiers and electronic filters, and can be transmitted to a remote location by electronic transmitters and received using electronic receivers. In Electrical engineering programs, a class and field of study known as "signals and systems" (S and S) is often seen as the "cut class" for EE careers, and is dreaded by some students as
Sonar signal processing and efficiency in data analysis . Thus, it is necessary to convert an analog signal into a digital signal by sample the signal in time domain . The operation can be realized by three devices: a digital conversion device, a dynamic range controller and a digital conversion device. For simplicity, the sampling is done at equal time intervals. In order to prevent the distortion (that is aliasing in frequency domain)after reconstruct the signal from sampled signal, one must sample at a faster rate .The sampling rate, which can well preserves the information content of an analog signal formula_1, is submitted