1. Signals Introduction Part 1

Flowchart nodes

• Signals Basics

• Signal

• Information

• Created when a value changes with time

• Created when a signal changes in an unpredictable way

• Side Notes

• An electrical/electronic circuit is some sort of signal processor

• Any value that changes as a function of time

• 12e6b349-472b-411c-8db8-420fcfac951e (image/png)

• A switch can create a signal

• The Unit Step can represent this simple signal

• 1dc03399-a4b7-4bfe-95df-c7e73ad6d772 (image/png)

• c47dae03-2e49-4526-aac2-d2c398461b31 (image/png)

• There's an infinite number of signals

• Some aspects of signals - can be used to classify them

• Amplitude

• Mean value (might be zero)

• Root mean square value (will not be zero)

• Number of zero crossings per unit time

• Related to frequency

• Important

• ee450d57-0649-4f0d-b0fb-d8a34d02316a (image/png)

• Electronic devices take an input signal and change it in some way

• Examples:AmplificationRectificationFiltering

• Fundamental Signal Classifications

• Continuous Signal

• Has a value at every point in time

• Discrete Time Signal

• Has a value at distinct points in time

• 44c64e37-1ed1-4088-a210-a6e16844bb18 (image/png)

• 2bb532b4-3ad3-407c-ac3b-a6df7de51171 (image/png)

• T is the time between the signal values (not the time period) in this case

• Signals can be created by summing other signals

• Simple signals, such as sine waves, are added to create more complicated wave-forms - information signals (maybe)

• 2d313521-9ce8-47fd-a6d0-14c105ac196e (image/png)

• cd0e4f14-3e63-4dba-9913-0e153fdf13da (image/png)

• Adding continuous signals

• Adding discrete time signals

• Periodic

• Random

• Non-periodic, Not Random

• Values are repeated at regular intervals (periods)

• Random value (can't be determined) at any point in time

• Values are not repeated periodically and are not random

• T = Period

• 2a97eee6-a194-453e-8a48-daef64cd054f (image/png)

• c3e59661-b55a-4f71-949f-e776c96c935f (image/png)

• Continuous Signals

• Random Signal

• 93336ff0-ec6a-4349-8196-a66767a195e1 (image/png)

• Discrete Random Signals

• f20ad80c-e482-4e97-b4da-705a86586e2a (image/png)

• Non-Periodic, Not Random Signal

• Odd

• Even

• x(t) = x(-t)

• x(t) = -x(-t)

• Symmetric

• Anti-symmetric

• (Cosine Wave)

• (Sine Wave)

• 571c0424-171d-46de-871e-ae740cd10dd7 (image/png)

• Signal Symmetry

• Product Rule

• ODD . ODD = EVENEVEN . EVEN = EVENEVEN . ODD = ODDODD . EVEN = ODD

• c4f4edba-b187-4edf-ab27-e36148b48125 (image/png)

• 11951b5d-1520-4132-b29f-b01d7edc4e79 (image/png)