Rise Time ↔ Bandwidth Calculator
Derive the equivalent signal bandwidth from edge rise time, or the edge from the bandwidth — for scope selection, sample rate and impedance-control decisions.
Key points
Rise Time ↔ Bandwidth Calculator: Derive the equivalent signal bandwidth from edge rise time, or the edge from the bandwidth — for scope selection, sample rate and impedance-control decisions. Formula: BW = 0.35 / t_r (Gaussian response). Enter parameters on the DD-CAT IDE online tool page to get results instantly, with a calculation-model diagram that updates with the inputs. System rise time adds in quadrature: t_total = √(t_source² + t_scope² + t_probe²), so a 1ns edge reads about 1.4ns on a 350MHz scope. Termination depends on the edge, not the clock: a slow clock with a fast edge still needs termination.
Inputs
BW = 0.35 / t_r (Gaussian response)Calculation model (updates with parameters)
| Equivalent bandwidth BW | 350 MHz | |
| Relationship | BW = 0.35 / t_r | t_r = 1.0000 ns |
| Highest square wave this edge supports | 500 MHz | f ≈ 0.5/t_r; beyond that the waveform becomes sinusoidal |
| Suggested scope bandwidth | 1.05 GHz | 3× the signal bandwidth keeps measurement error within 5% |
| Suggested sample rate | 1.75 GHz | 5× bandwidth (or 10× the highest signal frequency) |
| Bandwidth of a 1ns edge | 350 MHz | Quick memory aid: 1ns ↔ 350MHz |
Engineering notes
- System rise time adds in quadrature: t_total = √(t_source² + t_scope² + t_probe²), so a 1ns edge reads about 1.4ns on a 350MHz scope.
- Termination depends on the edge, not the clock: a slow clock with a fast edge still needs termination.
FAQ
- What is Rise Time ↔ Bandwidth Calculator for?
- Derive the equivalent signal bandwidth from edge rise time, or the edge from the bandwidth — for scope selection, sample rate and impedance-control decisions.
- What is the formula for Rise Time ↔ Bandwidth Calculator?
- Core formula: BW = 0.35 / t_r (Gaussian response). The tool returns results instantly using this formula and the selected parameters.
- What engineering notes should I keep in mind when using Rise Time ↔ Bandwidth Calculator?
- System rise time adds in quadrature: t_total = √(t_source² + t_scope² + t_probe²), so a 1ns edge reads about 1.4ns on a 350MHz scope. Termination depends on the edge, not the clock: a slow clock with a fast edge still needs termination.