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INPUT   DATA

♥ EXAMPLE Of Input/Output

Title

Frequency of source, fs		Hz
Speed of sound, vo		m/s
Speed of source, vs		m/s	Towards listener   Away from listener
Speed of listener, vl		m/s	Towards source   Away from source

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OUTPUT   VARIABLES   &   GRAPHS

Variables	Values	Units
♦  Frequency at listener location, fl		Hz

Doppler Effect In Sound

Doppler effect describes the change in the apparent frequency associated with a moving source and a moving observer (listener). If the source and observer are moving towards each other the perceived frequency is higher than the actual frequency. Likewise, if the source and observer are moving away from each other the perceived frequency is lower than the actual frequency.

The perceived frequency is related to the actual frequency and the relative speeds of the source, observer, and the speed of waves in the medium by:

   f_l = f_s [v_o + v_l]/[v_o - v_s]

where
     f_l = frequency as perceived by the observer
     f_s = frequency emitted by source
     v_o = speed of sound in air or the medium
     v_l = speed of the listener
     v_s = speed of source

Tips

    ◊ Use link EXAMPLE Of Input/Output  to demo data entry expectations and results; you may edit & use it as starting point

BIBLIOGRAPHY

• Bueche FJ & Hecht E; College Physics, Schaum's Outlines Series; McGraw Hill, New York, 1997.
• Davis D & Davis C; Sound System Engineering, Focal Press (An Imprint of Elsevier), Boston, USA, 1997