Difficulty: Easy
Correct Answer: 10 to 90 percent
Explanation:
Introduction:
Rise time is a key specification for digital signals, oscilloscopes, and amplifiers. It characterizes how quickly a waveform transitions from low to high. Using consistent percentage thresholds ensures repeatable measurements across instruments and datasheets.
Given Data / Assumptions:
Concept / Approach:
By convention, the rise time tr of a pulse is measured between 10% and 90% of the full amplitude. This avoids the flat extremes where noise and overshoot may dominate and provides a robust, comparable metric for bandwidth-related performance.
Step-by-Step Solution:
Verification / Alternative check:
Most oscilloscope manuals and high-speed design texts define rise time as 10–90%. Some applications use 20–80% or 5–95%, but 10–90% remains the default for general-purpose characterization and bandwidth estimation (e.g., BW ≈ 0.35 / tr for single-pole systems).
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
10 to 90 percent
Discussion & Comments