多普勒频移计算器 — 公式
## Doppler Effect for Sound
The Doppler effect shifts the observed frequency when the source or observer is moving relative to the medium.
### Formula
**f_obs = f_s * (c + v_obs) / (c + v_src)**
Sign convention: v_obs is positive when moving toward the source; v_src is positive when moving away from the observer.
- Source approaching: lower denominator, higher f_obs
- Source receding: higher denominator, lower f_obs
The Doppler effect shifts the observed frequency when the source or observer is moving relative to the medium.
### Formula
**f_obs = f_s * (c + v_obs) / (c + v_src)**
Sign convention: v_obs is positive when moving toward the source; v_src is positive when moving away from the observer.
- Source approaching: lower denominator, higher f_obs
- Source receding: higher denominator, lower f_obs
计算示例
A 440 Hz siren moves away at 30 m/s, observer stationary.
- f_obs = 440 * (343 + 0) / (343 + 30)
- f_obs = 440 * 343 / 373
- f_obs = 440 * 0.9196
- f_obs = 404.6 Hz (lower pitch)