Principle

If an emitter of sound or a detector is set into motion relative to the medium of propagation, the frequency of the waves that are emitted or detected is shifted due to the Doppler effect.

Benefits

• Easy frequency setting thanks to digital function generator
• Intuitive measuring instrument
• Results well reproducible because of the motor-driven car

Tasks

1. Measure the Doppler shift for varying frequencies and velocities for a moving sound emitter. Compare the measurements with the values predicted by theory and validate equation (4).
2. Measure the Doppler shift for varying frequencies and velocities for a moving detector. Compare the measurements with the values predicted by theory and validate equation (6).

Learning objectives

• Wave propagation
• Doppler shift of frequency