RF module


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A RF module presentation as a part of one complete course about using communication modules along with PIC-Micro-controller

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RF module

  1. 1. Communication PIC-Microcontroller Lab Course by JAOM Center, Feb. 2013 RF Module Instructor: Mohsen Sarakbi
  2. 2. Radio Frequency
  3. 3. Data Forms Data (Information) can be analog or digital. The term analog data refers to information that is continuous; digital data refers to information that has discrete states. Analog data take on continuous values. Digital data take on discrete values. In communication systems, we commonly use periodic analog signals and non-periodic digital signals
  4. 4. Signal Parameters x (t) = A(t) cos[w.t + (Ø)]
  5. 5. Signal Parameters Amplitude (A): is the peak of the signal
  6. 6. Signal Parameters Frequency (F): is the rate of change with respect to time. Change in a short span of time, means high frequency. Change over a long span of time means low frequency.
  7. 7. Signal Parameters Phase (P): describes the position of the waveform relative to time 0.
  8. 8. Modulation To be transmitted, Information (Data) must be transformed to electromagnetic signals, with higher frequency and power.
  9. 9. Modulation, Why?
  10. 10. Modulation, Why? Frequency Assignment Reduction of noise/interference Multiplexing Bandwidth limitations of equipment Frequency characteristics of antennas Atmospheric/cable properties
  11. 11. Modulation Analogue modulation:A higher frequency signal is generated by varying some characteristic of a highfrequency signal (carrier) on a continuous basis.Amplitude Modulation (AM), Frequency Modulation (FM), Phase Modulation(PM) Digital modulation:Signals are converted to binary data, encoded, and translated to higher frequency.Frequency Shift Keying (FSK), Binary Phase Shift Keying (BPSK) [ (GMSK)],Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation(QAM)
  12. 12. Amplitude Modulation (AM)
  13. 13. Frequency Modulation (FM)
  14. 14. Phase Modulation (PM)
  15. 15. Digital Modulation
  16. 16. Comparisons of Digital and AnalogCommunication Systems Digital Communication System Analog Communication System Advantage : Disadvantages :  inexpensive digital circuits  privacy preserved (data encryption)  expensive analog components : L&C  can merge different data (voice, video and data)  no privacy and transmit over a common digital  can not merge data from diff. sources transmission system  no error correction capability  error correction by coding Disadvantages : Advantages :  larger bandwidth  smaller bandwidth  synchronization problem is relatively difficult  synchronization problem is relatively easier
  17. 17. Time Domain vs. Frequency Domain
  18. 18. Time Domain vs. Frequency Domain
  19. 19. Manchester Encoding It is a form of binary phase-shift keying (BPSK) that has gained wide acceptance as the modulation scheme for low- cost radio-frequency (RF) transmission of digital data. Manchester is a simple method for encoding digital serial data of arbitrary bit patterns without having any long strings of continuous zeros or ones, and having the encoding clock rate embedded within the transmitted data. These two characteristics enable low-cost data-recovery circuits to be constructed that can decode transmitted data with variable signal strengths from transmitters with imprecise, low-cost, data-rate clocks.
  20. 20. Manchester Encoding
  21. 21. RF TX/RX Module
  22. 22. Specifications Range in open space(Standard Conditions) : 100 Meters RX Receiver Frequency : 433 MHz RX Typical Sensitivity : 105 dBm RX Supply Current : 3.5 mA RX IF Frequency : 1MHz Low Power Consumption Easy For Application RX Operating Voltage : 5V TX Frequency Range : 433.92 MHz TX Supply Voltage : 3V ~ 6V TX Out Put Power : 4 ~ 12 Dbm
  23. 23. PIN Layout
  24. 24. Decoders - Encoders Parallel encoders/decoders 4bits: HT12D / HT12E 8bits: CIP-8
  25. 25. HT12D Decoder Features:  Operating voltage: 2.4V~12V  Low power and high noise immunity CMOS technology  Low standby current  Capable of decoding 12 bits of information  Binary address setting  Received codes are checked 3 times  Address/Data number combination  8 address bits and 4 data bits
  26. 26. HT12E Encoder Features:  Operating voltage 2.4V~12V  Low power and high noise immunity CMOS technology  Low standby current: 0.1A (typ.) at VDD=5V  Four words  Built-in oscillator needs only 5% resistor  Data code has positive polarity
  27. 27. PIN Layout
  28. 28. CIP – 8bits Decoder/Encoder Features:  Latched or momentary outputs  No programming necessary  Very easy to use  Very low component count  Low current consumption  Up to 25mA per decoder output  Eight bit data (D0 to D7)  Eight bit binary address (0 to 255)  Selectable baud rates (2400/4800)  High noise immunity  Standard 20-pin PDIP package
  29. 29. PIN LayoutNote: All pins must be connected
  30. 30. Lab Test RF modules Application without PIC Application with PIC