Lecture I: Introduction to pattern recognition

1
EENG 3920 Project VI Modern Electronic
Communication
Lecture 2
2
1. Introductory Topics

• 1.8 Oscillators
• Converting energy from a dc form to ac

3
1. Introductory Topics

• 1.8 Oscillators
• Converting energy from a dc form to ac

Requirement

• Output frequency required
• Frequency stability required
• Is the frequency variable, and if so, over what
  range?
• Allowable waveform distortion
• Power output required

• Type
• LC Oscillator
• Hartley Oscillator
• Colpitts Oscillator
• Clapp Oscillator
• Crystal Oscillator

4
1. Introductory Topics

• 1.8 Oscillators
• Hartley Oscillator

Restore lost energy to provide a
constant-amplitude sine-wave output
5
1. Introductory Topics

• 1.8 Oscillators
• Colpitts Oscillator

6
1. Introductory Topics

• 1.9 Troubleshooting

• General Troubleshooting Techniques
• Look discolored or charred components might
  indicate overheating
• Smell Some components, especially transformers,
  emit characteristic odors when overheated
• Feel for hot components
• Listen for frying noise that indicate a
  component is about to fail

7
1. Introductory Topics

• 1.9 Troubleshooting

• Reasons Electronic Circuit Fail
• Complete failures open circuits, defective
  power supply, open power resistors. (Easiest)
• Intermittent faults loose wires and components,
  effects of temperature. (Most difficult)
• Poor system performance components change in
  value, weak power supply

8
1. Introductory Topics

• 1.9 Troubleshooting

• Troubleshooting Plan
• Symptoms as clues to faulty stages To relate a
  particular fault to a circuit function in the
  electronic equipment
• Signal Tracing and signal injection
• Voltage and resistance measurements
• Substitution

9
1. Introductory Topics

• 1.9 Troubleshooting

Signal Injection
Signal Tracing
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Assignment
1. Lab report (2) on Experiment 3 (Due
02/07)2. Homework (Due 02/07)