Presentation is loading. Please wait.

Presentation is loading. Please wait.

Naval Weapons Systems Energy Fundamentals Learning Objectives  Comprehend basic communication theory, electromagnetic (EM) wave theory  Comprehend.

Similar presentations


Presentation on theme: "Naval Weapons Systems Energy Fundamentals Learning Objectives  Comprehend basic communication theory, electromagnetic (EM) wave theory  Comprehend."— Presentation transcript:

1

2 Naval Weapons Systems Energy Fundamentals

3 Learning Objectives  Comprehend basic communication theory, electromagnetic (EM) wave theory  Comprehend radar and radio wave parameters including frequency, period, wavelength, velocity, and amplitude  Know Maxwell’s theory, relationship between wave parameters  Comprehend concepts of time and distance (wave phase angle) and interference

4 Learning Objectives (cont)  Know EM wave propagation principles such as reflection, refraction, diffraction, and ducting  Know the definition of sky, space, and ground waves

5 Energy Fundamentals  RAdio Detection And Ranging  Radar is an electromagnetic wave that acts like any other electromagnetic wave (i.e. - radio, light, etc.)  Characteristics of a radio wave assuming a frequency of 2 Hertz: Cycle Amplitude 1 second

6 Traveling Wave Characteristics  Frequency  Period  Wavelength  Velocity  Amplitude

7

8

9 Maxwell’s Theory  An accelerating electric field will generate a time-varying magnetic field.  A time-varying magnetic field will generate a time-varying electric field. ...and so on...and so on...and so on... Electric FieldMagnetic FieldElectric Field

10 Formation of Electric and Magnetic Fields around an Antenna e- E-line Mag field Electric field | Magnetic Field | Direction of Propagation.

11 Electromagnetic Spectrum

12 Propagation Paths of E-M Waves  Reflection  Refraction  Diffraction

13 ...Reflection... Incident Wave Reflected Wave Phase shift = 180 degrees. Angle of incidence = Angle of reflected wave.

14 -Incident wave passes through two transparent media in which the velocity of light differs... -Incident wave divides into a reflected wave and a refracted wave. The result is that the energy ray will bend toward the area of higher density....Refraction...

15 Snell’s Law n 1 * Sin θ 1 = n 2 * Sin θ 2

16 ...Diffraction... island not detected detected...plane waves traveling in a straight path bend around a boundary or obstruction.

17 Wave Propagation – Distance and Frequency  Ground Waves  Sky Waves  Space Waves

18 Ground Wave...  E-M energy travels along earth’s surface  Very low frequencies, 5-10Khz  Extremely long wavelengths  Shore communications stations (HF-DF)

19 Sky Wave...  E-M energy refracts toward earth’s surface in upper ionosphere layer  E-M energy then reflects back toward upper layer again  Frequencies to 550 KHz effectively  Fairly long wavelengths  Ship and Aircraft Communications

20 Space Wave...  E-M energy refracts back toward earth’s surface in outer space (i.e. stratosphere)  Above 30 MHz, ionosphere will not refract E-M waves back toward earth.

21 Transmission Range Factors  Antenna Height  Target Height  Ducting  Losses –Spreading –Absorption –Constructive Interference –Destructive Interference

22 Modulation  The process of encoding “Carrier Wave”  “Carrier Wave” has 3 independent parameters –Amplitude –Frequency –Phase

23 WHEW!

24 Questions?


Download ppt "Naval Weapons Systems Energy Fundamentals Learning Objectives  Comprehend basic communication theory, electromagnetic (EM) wave theory  Comprehend."

Similar presentations


Ads by Google