Tham khảo tài liệu 'communication systems engineering episode 1 part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Eytan Modiano Slide 1 Lectures 6 7 Modulation Eytan Modiano AA Dept. Modulation Representing digital signals as analog waveforms Baseband signals - Signals whose frequency components are concentrated around zero Passband signals - Signals whose frequency components are centered at some frequency fc away from zero Baseband signals can be converted to passband signals through modulation - Multiplication by a sinusoid with frequency fc Eytan Modiano Slide 2 Baseband signals The simplest signaling scheme is pulse amplitude modulation PAM - With binary PAM a pulse of amplitude A is used to represent a 1 and a pulse with amplitude -A to represent a 0 The simplest pulse is a rectangular pulse but in practice other type of pulses are used - For our discussion we will generally assume a rectangular pulse If we let g t be the basic pulse shape than with PAM we transmit g t to represent a 1 and -g t to represent a 0 1 S t g t g t A ------ 0 S t -g t Tb Eytan Modiano Slide
