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Coaxial Architecture

Coaxial Architecture

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Coaxial Architecture

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Presentation Transcript

  1. Coaxial Architecture

  2. Tree-and-Branch Architecture Express Trunk

  3. HFC Architecture HUBS node Tap Customer Homes Businesses amp in building

  4. Rural Network Other cable outputs Fiber Optic Cable RF (Node)Optics RX/TX Headend Active Device

  5. Near Passive Network Two-Way Tap Eight-Way Tap Directional Coupler Splitter 11 26 14 29 Headend or Node 29 Optics RX/TX 17 24 21 LPI Four-Way Tap LPS

  6. Passive Network 17 23 20 29 26 11 Two Way Tap Four Way Tap Slope Equalizer 17 Headend or Node Node 4

  7. Sample Headend 1 Analog Video Com21 55-550 MHz splitter 2 Way RF out 430MHz 2 Way HCX comController DT 815 Amp RF splitter 2 5008ET2 3 EDFA Hub Public switch EDFA 2RRX HUB Return TX 2RRX DWDD Return TX DWDM

  8. Connector Parts Body Boot Ferrule

  9. Types of Connectors FC ST Biconic D4 SC

  10. Optical Loss Example

  11. Coaxial Plant Designand Operation Optical Transmitters and Receivers

  12. Topics • Overview • Optical Transmitters • Optical Receivers • Units of Optical Power • Power Budget

  13. Optical Transmitter and Receiver Reproduced Electrical Signal Input ElectricalSignal Optical Signal Optical Fiber Transmitter Receiver

  14. Optical Transmitter Drive Level Control Drive Level Test Point RF Input Optical Fiber Optical Connector Laser

  15. Laser Drive Levels Clipped Output Laser Performance Curve Modulated Optical Output Optical Output Power Current Threshold Current Input RF Bias Current

  16. Optical Receiver Bias Voltage Fiber Optical Connector Test Point Photo Detector RF Out Pre Amp Post Amp

  17. Units of Optical Power

  18. Optical Power Equations dBm = 10 log mW mW = inverse log (dBm/10)

  19. +/-10dB Optical Power Table Optical Power (dBm)Optical Power (mW) 30 1,000 20 100 10 10 0 1 -10 0.1 -20 0.01 -30 0.001

  20. Power Budget Formula P b = T p - Rin where P b = the Power Budget T p = output Power of the Transmitter and R in = required input to the receiver

  21. Optical Node System RF out NOR NRT

  22. Optical Node Operation Post Amp H L 20 dBmV Post Amp H Pre Amp L Post Amp H L H L Node/Amplifier Block Diagram -20 dB Rf TP Light to RF Converter Splitter Level Control Tilt Generator Attenuator RF to Light Converter to RF Post Amp Combiner

  23. Forward Optical Receivers/NOR’S RF Gain adjust 9A pad Optical monitoring T/P -30 down Test Point Optical alarm

  24. Diamond Net RF Module

  25. Coaxial Plant Designand Operation Amplifier Technology

  26. Topics • Semiconductor Configurations in CATV • Single - Ended Amplifier • Push - Pull Amplifier • Parallel - Hybrid Amplifier

  27. Semiconductor Amplifier Configurations

  28. Single - Ended Amplifier 2nd Harmonic plus Noise

  29. Push - Pull Amplifier

  30. Parallel - Hybrid Amplifier Push Pull Stage Push Pull Stage Pin Pout ADVANTAGES: High Gain and Reduced Distortions

  31. Coaxial Plant Designand Operation Amplifier Configurations

  32. Objectives • Describe the most common amplifier configurations and discuss their usage. • Identify the components for each of the amplifier configuration and explain their functions and importance.

  33. Forward Amplifier Characteristics

  34. Amplifier Output Tilt 11dB of tilt @ 750 MHz

  35. Attenuator Function 20 dBmV 20 dBmV 10 dBmV 10 dBmV 0 dBmV 0 dBmV 750 MHz 750 MHz 50 MHz 50 MHz

  36. Equalizer Function Effect of Cable 20 dBmV 10 dBmV 10 dBmV 0 dBmV 750 MHz 50 MHz Combined Results 0 dB 750 MHz 50 MHz 10 dB Effect of Equalizer 20 dB 750 MHz 50 MHz

  37. Response Equalizer Examples of Peak to Valley Responses. With Response Equalizers Installed These are available in either bumps or traps

  38. Equalizer Selection 20 dB 11 dB Interstage Eq Set for desired Tilt @ Output Secondary Eq Set Additional Tilt 12 dB 50 MHz 750 MHz 11 dB = = = 8 dB 62E750/11 50 MHz 750 MHz

  39. DC TP High Low Post Amp Pad Input EQ ALSC Optional Plug In Input Atten Interstage Slope Eq. Manual Gain Adj. Response Equalizer Interstage Atten. Inter Stage Amp Pre Amp Dist EQ High High DC TP Pad Low Low Shorting Stub to One Secondary or DC 4-8-or 12 Post Amp High DC TP Low Amplifier Block Diagram withALSC / AGC

  40. Forward Amplifier Characteristics

  41. Forward Sweep SYSTEM AMPLIFIER SWEEP GEAR METER

  42. Sweep System Requirements Fiber Optic Interconnect Headend Combiner Fiber Transmitter Sweep Transmitter Node AMP 1 Reference Amp 4 Amp 2 Amp 3 Amp 5 Amp 6 *The remaining amplifiers in the cascade are compared to the reference.

  43. Raw Sweep AFTER BEFORE

  44. Low Level Signal Telemetry

  45. Coaxial Plant Designand Operation Frequency Response Specifics

  46. Non Linear Cable Loss Characteristics Cable Kinks Z Mismatch Ideal Response Signal Level Signal Level 550MHz 50 MHz 550MHz 50 MHz Non Linear

  47. Hardware Points of Concern Amplifier Connector Tap Cable Cable Cable Connector

  48. Frequency Characteristics

  49. Peak to Valley

  50. Impedance Mismatch