Jewel Trace Oscilloscope

Introduction

• Discusses block diagram and operation of Jewel Trace Oscilloscope.
• Comparison with Jewel Beam Oscilloscope (both are different).

Block Diagram Overview

• Channel A and B: Represents two types of signals to display on CRT screen.
• Vertical Deflection Plates: In dual beam oscilloscope, two vertical deflection plates were used. In jewel trace oscilloscope, only one set of vertical reflection plates is used for both channels.
• Horizontal Deflection Plates: Same as in dual beam oscilloscope.

Vertical Amplifier Section

• Preamplifier and Attenuator: Known as vertical amplifier (wideband amplifier).
  • Includes FET input amplifier and BJT main amplifier.
• Delay Line: Added before applying the signal to vertical deflection plates to synchronize with the horizontal deflection system.
• Electronic Switch: Unique to dual trace oscilloscope, connected to both channel A and B.

Horizontal Deflection System

• Components: Trigger pulse generator, Sweep generator, Horizontal amplifier.
• Trigger Circuit: Input can come from internal signal, external signal, or line supply.
• Sweep Generator: Produces sweeps; sawtooth waveform generator.

Electronic Switch Operation

• Modes of Operation:
  • Alternate Mode: Switch selects channel A for one sweep and channel B for the next.
  • Chop Mode: Within a single sweep cycle, quickly alternates between channel A and B. Cuts signal into small pieces (chopping).

XY Mode

• Purpose: Generates Lisajous patterns when both vertical and horizontal plates are driven by sinusoidal signals.
• Patterns: Depends on phase difference between the signals of channel A and B (e.g., circular, oval, rectangular).
• Use: Measure unknown frequency (detailed in future videos).

Summary

• Jewel Trace Oscilloscope Key Points:
  • Uses one set of vertical and horizontal deflection plates.
  • Employs electronic switch to alternate between signals from channel A and B.
  • Includes XY mode for generating Lisajous patterns.
• Operation Modes: Alternate and Chop modes for different waveform displays.