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Angle Modulation

Angle Modulation. Angle Modulation. General Format Phase Instantaneous Frequency. Phase and Frequency Modulation. Waveform Base band PM FM Constant amplitude No static noise Modulation Index m inversely proportional to f m for FM Spectrum Bessel functions Broader bandwidth

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Angle Modulation

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  1. Angle Modulation

  2. Angle Modulation • General Format • Phase • Instantaneous Frequency

  3. Phase and Frequency Modulation • Waveform • Base band • PM • FM • Constant amplitude • No static noise • Modulation Index • m inversely proportional to fm for FM • Spectrum • Bessel functions • Broader bandwidth • Carson’s rule B=2(+fmax)

  4. FM Java • http://contact.tm.agilent.com/Agilent/tmo/an-150-1/classes/liveFM_popup.html

  5. FM Noise • Amplitude • Controlled by limiter • Driving into saturation • Phase • Phasor picture • Maximum angle deviation • White noise

  6. Frequency Error by Phase Noise • Simplified S/N Analysis • Signal frequency: 1 kHz • Signal amplitude, ES: 10 • Frequency deviation: 5 kHz • Noise amplitude, EN: 1 • (S/N)P: 20 dB • Maximum angle deviation: 0.1 rad • Noise modulation index, mN: 0.1 • Frequency error caused by noise • 1 kHz x 0.1 = 100 Hz • (S/N)F: 5 kHz/100 Hz = 50; 34 dB in power

  7. FM Noise • Threshold and Capture Effect • S/N below threshold: poor performance • S/N above threshold: improved performance • Strong station dominates weak station

  8. FM Noise • Noise in FM system • Frequency error: mNfm • Larger signal needed at higher frequency • Pre-emphasis and de-emphasis • High pass and low pass filters

  9. FM Radio • Source • Audio, 50-15 kHz • Carrier Frequency • 88 – 108 MHz • IF • 10.7 MHz • Performance • 15 kHz bandwidth • 50-100 km range • 10 µV sensitivity

  10. FM Radio

  11. Block Diagram

  12. FM Modulator Circuits • Varactor • Variable Reactance Modulator

  13. FM Detector Circuits • FM Detection • Convert frequency deviation to voltage • Frequency dependent throughput • Slope detector • Discriminator • Project

  14. FM Detector Circuits • Quadrature demodulator tutorial • PLL

  15. FM Stereo - Frequency Allocation • Sub-Carrier • Multiplexing

  16. Stereo Transmitter • Frequency Division Multiplexing • 19 kHz Pilot • Preemphasis

  17. Stereo Receiver

  18. Practical Circuits • FM Transmitter • http://www.free-electronic-circuits.com/circuits/fm-transmitter.html • Regenerative Receiver • http://www.somerset.net/arm/fm_only_one_transistor_radio.html

  19. IC-Based FM Radio

  20. Digital Audio Broadcasting • Eureka • Britain: Band III, 174-240 MHz • Canada: L-Band, 1452 to 1492MHz • Data: 192 kb/s, digital compression • iBiquity • In band on channel • Analog + digital sideband • Perceptual audio coder • http://beradio.com/mag/radio_iboc_transmission/index.html • http://www.broadcastpapers.com/whitepapers/BAsia04BcastElectHDRadio.pdf • Sirius and XM Radio

  21. Television

  22. Analog TV • Standard • NTSC, PAL, SECAM • Broadcasting • Local station, CATV, satellite • HDTV • Monitor

  23. NTSC Signaling • Vertical Scan Lines • 525 lines (625) • Aspect Ratio • 4:3 • Frame Rate • 30 Hz (25 Hz) interlaced • 525 lines/frame x 30 frames/sec = 15.75 kHz • Resolution: • 0.7-0.75 utilization factor

  24. NTSC Broadcasting 4.75 3.579545

  25. Analog TV Signaling • Composite Video • Luminance (brightness) ~340 lines • Y=0.3R+0.5G+0.11B • Chrominance (color); 50-100 lines • I=0.6R-0.28G-0.32B • Q=0.21R-0.52G+0.31B • H Sync • V Sync • Blanking • Color burst • Reference

  26. Waveforms

  27. Spectrum • Luminance • AM vestigial side band • From -0.75 MHz to +4 MHz • Chrominance • QUAM VSBSC • Pilot at 3.58 MHz • Sound • FM • Sub-carrier at 4.5 MHz

  28. TV Receiver Circuits • RF, IF • 45 MHz • Video Detector • Composite Video to RGB • Comb filter • Audio IF, Audio Detector • Sync Separator • H Sync • V Sync • TV Circuit Chips http://www.nteinc.com/linear_web/tv.html

  29. Block Diagram

  30. Display - CRT • CRT • Control, acceleration, focusing, deflection, shadow mask, purity, convergence • Picture-in-picture (PIP)

  31. Video Image Sensors • Vidicon • CCD • http://spiff.rit.edu/classes/phys445/lectures/ccd1/ccd1.html • CMOS • http://micro.magnet.fsu.edu/primer/digitalimaging/cmosimagesensors.html

  32. CATV System • Video Signal Distribution • Source • Fiber trunk, linear modulator • Headend • Coax distribution, amplifier, splitter • Pay per View • Cable Modem • Reference • http://people.deas.harvard.edu/ ~jones/cscie129/nu_lectures/ lecture13/CATV/CATV.html

  33. Digital Set Top Box http://www.xilinx.com/esp/consumer/home_networking/pdf_files/stb_to_rg/stb_complete.pdf Source: TI

  34. High-Definition TV • Analog MUSE • 1125 lines, 20 MHz • Digital TV • 1920x1080, 6 MHz • Compression

  35. Digital TV

  36. HDTV Signaling • MPEG-2 • 19.39 Mbps • http://www.bretl.com/mpeghtml/MPEGindex.htm • 8-VSB • http://www.broadcast.net/~sbe1/8vsb/8vsb.htm

  37. Other Display Technologies • LCD • Plasma Display Panel • Other Display Technologies • OLED • Field emission • Electroluminescent display • E-Ink • Projection • LCOS • Digital light processor • Grating light valve http://www.hdtvmagazine.com/downloads/Display%20Wars%20-%20Flat%20Panels%20(InfoComm%202005).ppt

  38. Chapter Review • FM and PM • Modulation Index and Side Bands • Phase Noise and FM Noise Analysis • Limiter and S/N Improvement • FM Modulator • FM Detection • NTSC • DTV • CATV • Display Technologies

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