Howtosignalprocessing
Just as a microphone collects sound in the air, a hydrophone detects acoustic signals under the water. Most hydrophones are based on a special property of certain ceramics that produces a small electrical current when subjected to changes in underwater pressure.
How far can hydrophones hear?
Using an underwater microphone called a hydrophone, a second boat stationed 900 miles away successfully detected the sounds. Subsequent tests picked up the signal at a distance of 3,000 miles.
Are hydrophones still in use?
From late in World War I until the introduction of active sonar in the early 1920s, hydrophones were the sole method for submarines to detect targets while submerged; they remain useful today.
What is measured when using a hydrophone?
Hydrophones are designed to measure the mechanical sound pressure in water. Most hydrophone sensors are piezoelectric materials which convert mechanical energy to electrical energy.
