Canonical: https://echosuite.app/guides/pulse-repetition/

# Pulse repetition and Nyquist calculator

Explore pulse repetition and nyquist with the method’s inputs, acquisition guidance and source references. Open the calculator to enter measurements or try an illustrative worked example.

Created by [Mohammed Kamareddine, MD](https://echosuite.app/about/) · [Sources & educational scope](https://echosuite.app/about/)

[Open interactive calculator →](https://echosuite.app/calculators/#pulse-repetition)

## Method

PRPmin ≈ 13 × depth; PRF = 1/PRP; Nyquist = PRF/2; duty = PD/PRP

Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.

## Measurements and acquisition

### Start from

Enter the measured value in the displayed unit

- Depth limit
- Known PRF
- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Sample depth  cm

Enter the measured value in the displayed unit

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Pulse repetition frequency  kHz

Enter the measured value in the displayed unit

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Pulse duration · PD  µs

Enter the measured value in the displayed unit · Optional

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

### Peak Doppler shift · |Δf|  kHz

Enter the measured value in the displayed unit · Optional

- Confirm the variable matches the selected formula.
- Use the unit displayed beside the field.
- Keep measurements from the same representative hemodynamic state.

## Sources and method context

Cambridge University Press · 2016 · Manual of Neurosonology · Ultrasound principles · Chapter 1 · Figures 1.3 and 1.6; PW Doppler and Nyquist, pp. 3–6

[Primary reference](https://assets.cambridge.org/97811076/59155/excerpt/9781107659155_excerpt.pdf)

- Range and sampling · Chapter 1 · pulse timing and PW Doppler

Round-trip time limits conventional unambiguous PRF. Nyquist is half the PRF; CW removes pulsed aliasing while losing sample-depth selection.

- Duty factor · ASE Echocardiography Formula Review Guide Part 2 · principles of waves and sound

Duty factor is pulse duration divided by repetition period. The 13 µs/cm depth relation is a rounded soft-tissue approximation, not a scanner setting.

Catalogue review status: Source mapped · clinical sign-off pending

These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.

## Keep exploring

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- [Pulse length and near field calculator](https://echosuite.app/guides/pulse-geometry/)
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