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Radio Communication Basics and Modulation Techniques

Learn the fundamentals of radio communication, including how information is transmitted, received, and modulated. Understand modulation techniques like AM and phase. Dive into the fascinating world of ham radios and how they work.

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Radio Communication Basics and Modulation Techniques

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  1. Technician License Course

  2. Technician License Course Chapter 2 Lesson Plan Module - 3 Modulation & Bandwidth

  3. The Basic Radio Station

  4. What Happens During Radio Communication?

  5. What Happens During Radio Communication? • Transmitting (sending a signal):

  6. What Happens During Radio Communication? • Transmitting (sending a signal): • Information (voice, data, video, commands, etc.) is converted to electronic form.

  7. What Happens During Radio Communication? • Transmitting (sending a signal): • Information (voice, data, video, commands, etc.) is converted to electronic form. • The information in electronic form is added to a radio wave.

  8. What Happens During Radio Communication? • Transmitting (sending a signal): • Information (voice, data, video, commands, etc.) is converted to electronic form. • The information in electronic form is added to a radio wave. • The radio wave carrying the information is sent from the station antenna into space.

  9. What Happens During Radio Communication?

  10. What Happens During Radio Communication? • Receiving:

  11. What Happens During Radio Communication? • Receiving: • The radio wave carrying the information is intercepted by the receiving station’s antenna.

  12. What Happens During Radio Communication? • Receiving: • The radio wave carrying the information is intercepted by the receiving station’s antenna. • The receiver extracts the information from the received wave.

  13. What Happens During Radio Communication? • Receiving: • The radio wave carrying the information is intercepted by the receiving station’s antenna. • The receiver extracts the information from the received wave. • The information is then presented to the user in a format that can be understood (sound, picture, words on a computer screen, response to a command, etc.).

  14. What Happens During Radio Communication?

  15. What Happens During Radio Communication? • Adding and extracting the information can be simple or complex.

  16. What Happens During Radio Communication? • Adding and extracting the information can be simple or complex. • This makes ham radio fun…learning all about how radios work.

  17. What Happens During Radio Communication? • Adding and extracting the information can be simple or complex. • This makes ham radio fun…learning all about how radios work. • Don’t be intimidated. You will be required to only know the basics, but you can learn as much about the “art and science” of radio as you want.

  18. Adding Information – Modulation

  19. Adding Information – Modulation • When we add some information to the radio wave, (the carrier) we modulate the wave.

  20. Adding Information – Modulation • When we add some information to the radio wave, (the carrier) we modulate the wave. • Turn the wave on and off (Morse code)

  21. Adding Information – Modulation • When we add some information to the radio wave, (the carrier) we modulate the wave. • Turn the wave on and off (Morse code) • Speech or music

  22. Adding Information – Modulation • When we add some information to the radio wave, (the carrier) we modulate the wave. • Turn the wave on and off (Morse code) • Speech or music • Data

  23. Adding Information – Modulation • When we add some information to the radio wave, (the carrier) we modulate the wave. • Turn the wave on and off (Morse code) • Speech or music • Data • Different modulation techniques vary different properties of the wave to add the information:

  24. Adding Information – Modulation • When we add some information to the radio wave, (the carrier) we modulate the wave. • Turn the wave on and off (Morse code) • Speech or music • Data • Different modulation techniques vary different properties of the wave to add the information: • Amplitude, frequency, or phase

  25. Phase

  26. Phase • Along with frequency and period, another important property of waves is phase.

  27. Phase • Along with frequency and period, another important property of waves is phase. • Phase is a position within a cycle.

  28. Phase • Along with frequency and period, another important property of waves is phase. • Phase is a position within a cycle. • Phase is also a relative position between two waves.

  29. CW - Morse Code – On and Off

  30. CW - Morse Code – On and Off

  31. Amplitude Modulation (AM)

  32. Amplitude Modulation (AM) • In AM, the amplitude of the carrier wave is modified in step with the waveform of the information (the tone shown here).

  33. Composite Signals

  34. Composite Signals • The process of adding information to an unmodulated radio wave creates additional signals called sidebands.

  35. Composite Signals • The process of adding information to an unmodulated radio wave creates additional signals called sidebands. • The sidebands and carrier work together to carry the information. • .

  36. Composite Signals • The process of adding information to an unmodulated radio wave creates additional signals called sidebands. • The sidebands and carrier work together to carry the information. • The combination of carrier and sidebands creates a composite signal.

  37. Bandwidth

  38. Bandwidth • The carrier and sidebands have different frequencies, occupying a range of spectrum space.

  39. Bandwidth • The carrier and sidebands have different frequencies, occupying a range of spectrum space. • The occupied range is the composite signal’s bandwidth.

  40. Bandwidth • The carrier and sidebands have different frequencies, occupying a range of spectrum space. • The occupied range is the composite signal’s bandwidth. • Different types of modulation and information result in different signal bandwidths.

  41. Characteristics of Voice AM

  42. Characteristics of Voice AM AM signals consist of three components: Carrier LSB USB Amplitude 799.4 800 800.6 Frequency (kHz) AM signal being modulated by a 600 Hz tone

  43. Characteristics of Voice AM • AM signals consist of three components: • Carrier Carrier LSB USB Amplitude 799.4 800 800.6 Frequency (kHz) AM signal being modulated by a 600 Hz tone

  44. Characteristics of Voice AM • AM signals consist of three components: • Carrier • Lower sideband (LSB) Carrier LSB USB Amplitude 799.4 800 800.6 Frequency (kHz) AM signal being modulated by a 600 Hz tone

  45. Characteristics of Voice AM • AM signals consist of three components: • Carrier • Lower sideband (LSB) • Upper sideband (USB) Carrier LSB USB Amplitude 799.4 800 800.6 Frequency (kHz) AM signal being modulated by a 600 Hz tone

  46. Characteristics of Voice AM • AM signals consist of three components: • Carrier • Lower sideband (LSB) • Upper sideband (USB) • AM bandwidth is twice the information bandwidth. Carrier LSB USB Amplitude 799.4 800 800.6 Frequency (kHz) AM signal being modulated by a 600 Hz tone

  47. Characteristics of Voice Information

  48. Characteristics of Voice Information • Sounds that make up voice are a complex mixture of multiple frequencies from 300–3000 Hz

  49. Characteristics of Voice Information • Sounds that make up voice are a complex mixture of multiple frequencies from 300–3000 Hz • Two mirror-image sets of sidebands are created, each up to 3000 Hz wide.

  50. Characteristics of Voice Information • Sounds that make up voice are a complex mixture of multiple frequencies from 300–3000 Hz • Two mirror-image sets of sidebands are created, each up to 3000 Hz wide. • AM voice signal bandwidth 2 x 3000 Hz = 6000 Hz

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