Angle Modulation Angle Modulation General Format Phase Instantaneous

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 fm for FM • Spectrum – Bessel functions – Broader bandwidth • Carson’s rule B=2( +fmax)

FM Java • http: //contact. tm. agilent. com/Agilent/tmo/an-1501/classes/live. FM_popup. html

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

Frequency Error by Phase Noise • Simplified S/N Analysis – Signal frequency: 1 k. Hz – Signal amplitude, ES: 10 – Frequency deviation: 5 k. Hz – Noise amplitude, EN: 1 • (S/N)P: 20 d. B • Maximum angle deviation: 0. 1 rad • Noise modulation index, m. N: 0. 1 – Frequency error caused by noise • 1 k. Hz x 0. 1 = 100 Hz – (S/N)F: 5 k. Hz/100 Hz = 50; 34 d. B in power

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

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

FM Radio • Source – Audio, 50 -15 k. Hz • Carrier Frequency – 88 – 108 MHz • IF – 10. 7 MHz • Performance – 15 k. Hz bandwidth – 50 -100 km range – 10 µV sensitivity

FM Radio

Block Diagram

FM Modulator Circuits • Varactor • Variable Reactance Modulator

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

FM Detector Circuits • Quadrature demodulator tutorial • PLL

FM Stereo - Frequency Allocation • Sub-Carrier – Multiplexing

Stereo Transmitter • Frequency Division Multiplexing • 19 k. Hz Pilot • Preemphasis

Stereo Receiver

Practical Circuits • FM Transmitter – http: //www. free-electroniccircuits. com/circuits/fmtransmitter. html • Regenerative Receiver – http: //www. somerset. net/arm/fm_ only_one_transistor_radio. html

IC-Based FM Radio

Digital Audio Broadcasting • Eureka – Britain: Band III, 174 -240 MHz – Canada: L-Band, 1452 to 1492 MHz – Data: 192 kb/s, digital compression • i. Biquity – In band on channel • Analog + digital sideband – Perceptual audio coder – http: //beradio. com/mag/radio_iboc_transmission/index. html – http: //www. broadcastpapers. com/whitepapers/BAsia 04 Bcas t. Elect. HDRadio. pdf – Sirius and XM Radio

Television

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

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 k. Hz • Resolution: – 0. 7 -0. 75 utilization factor

NTSC Broadcasting 4. 75 3. 579545

Analog TV Signaling • Composite Video – Luminance (brightness) ~340 lines • Y=0. 3 R+0. 5 G+0. 11 B – Chrominance (color); 50 -100 lines • I=0. 6 R-0. 28 G-0. 32 B • Q=0. 21 R-0. 52 G+0. 31 B – – H Sync V Sync Blanking Color burst • Reference

Waveforms

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

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

Block Diagram

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

Video Image Sensors • Vidicon • CCD – http: //spiff. rit. edu/classes/phys 4 45/lectures/ccd 1. html • CMOS – http: //micro. magnet. fsu. edu/pri mer/digitalimaging/cmosimages ensors. html

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/cscie 129/nu_lectures/ lecture 13/CATV. html

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

High-Definition TV • Analog MUSE • 1125 lines, 20 MHz • Digital TV • 1920 x 1080, 6 MHz • Compression

Digital TV

HDTV Signaling • MPEG-2 – 19. 39 Mbps – http: //www. bretl. com/mpeghtml/MPEGindex. htm • 8 -VSB • http: //www. broadcast. net/~sbe 1/8 vsb. htm

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%20 Wars%20%20 Flat%20 Panels%20(Info. Comm%202005). ppt

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