Signals Cont

Control of Signals o    Signal can be controlled by three attributes:    Amplitude    Frequency    Phase Control of Signals- Amplitude

Time and Frequency Domain o    Time Domain plots show changes in signal amplitude w.r.t Time o    It is an Amplitude versus Time Plot o    Phase and Frequency are not explicitly measured on a Time domain plot o    To  show  the  relationship  between  amplitude  and  Frequency,  we  can  use  what  is called a Frequency Domain Plot o    Figure  compares  the  time  domain  (instantaneous  amplitude  w.r.t  Time)  and  the Frequency domain (Max amplitude w.r.t Frequency) o    Low Frequency signal in frequency domain corresponds to a signal with longer period in Time domain & vice versa. o    A   signal   changing   rapidly   in   Time   domain   corresponds   to   High   frequency   in Frequency domain o    Figure shows 3 signals with different frequencies and its time and frequency domain presentations Composite Signals o    Second type of Analog Signals, that is composed of multiple sine waves o    So far we have been focused on simple periodic signals or sine waves o    Many useful sine waves do not change in a single smooth curve b/w minimum and maximum amplitude. o    They jump, slide , wobble and spikeAs long as as any irregularities are consistent, cycle after cycle, a signal is still Periodic o    It   can   be   shown   that   any   periodic   signal   no   matter   how   complex   can   be decomposed into a collection of sine waves, each having a measurable amplitude, frequency & phase o    We   need   FOURIER   ANALYSIS   to   decompose   a   composite   signal   into   its components