1. F ACULTY OF C OMPUTER S CIENCE & E NGINEERING Chapter 02. Radio Frequency

2. F ORMATION OF R ADIO F REQUENCY Carrier Wave is Sin signal have high frequency in which it will have components such as phase or amplitude will vary according to the signal wave, waves to create high-rise to bring these signals in space

3. F ORMATION OF R ADIO F REQUENCY

4. O BJECTIVES Questions about the waves? Wave mechanics of natural Concept Amplitude Wave length Phare Cycle Frequency

5. O BJECTIVES Formation Of Electromagnetic Waves Electric Fields Magnetic Fields Electromagnetic Fields Electromagnetic Waves And Radio Communication The Operation Of The Radio Waves Concept Carrier Wave Modulation methods Carrier Wave Frequency range of applications in wireless media.

6. O BJECTIVES RF Behaviors ■ Gain ■ Loss ■ Reflection ■ Refraction ■ Diffraction ■ VSWR The Units Used In Radio Communication

7. Q UESTIONS ABOUT THE WAVES ? What is the wave ? What is the shape wave ? How is the wave active ? Define of Amplitude, Cycle, Frequency, Phase What is bandwidth? What frequency band? What is 3G, GSM,CDMA ……?

8. Q UESTIONS ABOUT THE WAVES ? Why do we hear the sound coming from far away? Why do we listen to the radio at night better normal? Why do we communicate with each other via phone ? Why was the data transmitted through outer space ? We want to watch TV, listen to the radio antenna must be why? Meaning of UHF, VHF.

9. W AVE MECHANICS OF NATURAL

10. For waves on the water above, the oscillation perpendicular to the direction of wave propagation. It is the shear wave Has the oscillation wave coincides with that of wave propagation along the wave. Sound waves as we speak, it is a longitudinal wave

11. RF C HARACTERISTICS All RF waves have characteristics that vary to define the wave. Some of these properties can be modified to modulate information onto the wave. These properties are wavelength, frequency, amplitude, and phase.

12. A MPLITUDE Amplitude is high, the strength or power of the wave

13. W AVELENGTH Wavelength is the distance between two points on two similar consecutive wave crests

14. P HASE

15. C YLE, F REQUENCY What cycle? What is the frequency? Frequency is the number of vibrations per unit time and is equal to f = 1 / T. Longer period is the time to perform a full oscillation.

16. C YLE, F REQUENCY The impact of frequency usage on WLANs is tremendous. By using different frequencies, you can enable distinct connections or RF links in a given coverage area or cell. For example, an IEEE 802.11g network using channel 1 can exist in the same cell as an IEEE 802.11g network using channel 11. This is because these channels use different frequencies that do not cancel or interfere with each other.

17. S OUND WAVES AND S OUND FEELINGS Example : When you shake a piece of mild steel plates that we found lower vibration When we rung steel plate with a larger force Ears begin to hear a certain gently, that is, pieces of steel that has a sound start Human ear is sensing the oscillation frequency from about 16Hz to 20.000Hz. Sound waves in any solid, liquid, gas Mechanical waves with frequencies greater than 20.000Hz called ultrasonic

18. E LECTROMAGNETIC W AVES An electromagnetic wave is a propagating combination of electric and magnetic fields. In terms of nature, electricity and magnetism are manifestations of a separate unified field called electromagnetic fields

19. E LECTRIC F IELDS Example : When an AC is running. It immediately generates an electric field around it In general the electric field is the physical environment surrounding the special charge In terms of nature, electricity and magnetism are manifestations of a separate unified field called electromagnetic fields

20. M AGNETIC F IELDS Example : When an AC is running. We move the wires of the electric current is running. It immediately generates a magnetic field. In terms of nature, electricity and magnetism are manifestations of a separate unified field called electromagnetic fields

21. E LECTROMAGNETIC W AVES Principle Macxoen Electromagnetic field due to a charge of vertical vibrations generated at O will spread in space as waves. Wave which is called electromagnetic waves. Hecxo the first to develop the electromagnetic wave The velocity of electromagnetic waves is 300.000km/s. Coincides with the velocity of the light

22. E LECTROMAGNETIC WAVES AND RADIO COMMUNICATION. Applications of Electromagnetic waves : Rada Radio astronomy Radio-controlled In the radio communication Waves with frequencies from thousands hectares or more, known as radio waves.

23. E LECTROMAGNETIC WAVES AND RADIO COMMUNICATION. The radio waves are classified into the following categories

24. E LECTROMAGNETIC WAVES AND RADIO COMMUNICATION. Characteristics of waves : Long and ultra long wave Less water absorption They are used to communicate underwater Normal wave During the day they are strongly absorbed by the ionosphere, so far not been transmitted So the night medium wave radio better day

25. E LECTROMAGNETIC WAVES AND RADIO COMMUNICATION. Characteristics of waves : Short wave ( Microwave) They are reflective ionosphere on the ground So a short radio stations with large capacity can wave to all locations on the ground. Supper Short wave ( Microwave) The microwave has the largest energy Ionosphere are not absorbed or reflected Used in information space

26. E LECTROMAGNETIC WAVES AND RADIO COMMUNICATION. Man-made radio waves like? Principles of operation of a radio transmitter

27. E LECTROMAGNETIC WAVES AND RADIO COMMUNICATION.

28. High-frequency waves is called carrier Carrier Wave is Sin signal have high frequency in which it will have components such as phase or amplitude will vary according to the signal wave, waves to create high-rise to bring these signals in space

29. M ODULATION METHODS Definition digital Digital data Analog data Digital data Digital signal Analog signal Analog data Digital signal Analog signal

30. M ODULATION METHODS Vary amplitude call amplitude Vary frequency call frequency Vary phare call phare Modulated at the digital data: Amplitude Shift Keying – ASK Frequency Shift Keying- FSK Phase Shift Keying –PSK

31. M ODULATION METHODS

32. Modulated at the analog data: AM (Amplitude Modulation) FM (Frequency Modulation) PM (Phase Modulation)

33. M ODULATION METHODS

34. RF B EHAVIORS RF waves that have been modulated to contain information are called RF signals. These RF signals have behaviors that can be predicted and detected ■ Gain ■ Loss ■ Reflection ■ Refraction ■ Diffraction ■ Scattering ■ VSWR

35. RF B EHAVIORS GAIN Increase in an RF signal's amplitude. Conventional amplifier is an active process But the process is passive amplification can occur.

36. RF B EHAVIORS

37. LOSS Described as the decline of signal strength There are many causes of the radio wave attenuation

38. RF B EHAVIORS

39. Reflection When an RF signal bounces off of a smooth, nonabsorptive surface, changing the direction of the signal, it is said to reflect and the process is known as reflection.

40. RF B EHAVIORS

41. Refraction Refraction occurs when an RF signal changes speed and is bent while moving between media of different densities.

42. RF B EHAVIORS

43. Diffraction is often caused by buildings, small hills, and other larger objects in the path of the propagating RF signal.

44. RF B EHAVIORS

45. VSWR

46. RF B EHAVIORS Voltage Standing Wave Radio VSWR values are often found to be 1.5: 1 EX: 1:1 VSWR value combination perfect impedance Influence VSWR Reduce the amplitude of radio waves This capacity can burn the circuit area

47. RF B EHAVIORS Solutions for VSWR Never use a cable to a device 75 Om 50 Om cable The equipment needs to be synchronized

48. R ADIO F REQUENCY M ATHEMATICS There are four parameters are calculated in the WLAN: Power at the transmitting device The attenuation and amplification devices connected Capacity at the last connector before the antenna Power at the antenna elements (EIRP)

49. R ADIO F REQUENCY M ATHEMATICS W (Watt) of the basic unit of power is Watt (W) 1 W is defined as an electric current is 1 A and 1 V EX: Light used 120 V will have 7 W. In a totally dark 7W bulb is visible from about 83 km away from it in all directions

50. R ADIO F REQUENCY M ATHEMATICS Miliwatt ( mW) Often, the power level of WLAN rarely exceed 100 mW 100 mWcan transmitting data to 0.8 km 1 W= 1000 mW

51. R ADIO F REQUENCY M ATHEMATICS Units of dB and dBm Measurement Units amplification and attenuation Unit dBm is a unit of absolute power

52. R ADIO F REQUENCY M ATHEMATICS Have unit conversion table as follows

53. R ADIO F REQUENCY M ATHEMATICS EX: Transfer from dBm to W units We have 43 = 10 + 10 + 10 +10 + 3 So infer 10 dBm based on the first panel would be 10 mW Or 1mW x 10 = 10 mW 10mW x 10 = 100 mW 100 mW x10 = 1000mW 1000mW x 10 = 10,000 mW 10,000mW x2 = 20,000 mW = 20 W

54. R ADIO F REQUENCY M ATHEMATICS Unit dBi Amplification antenna

55. The END