Why does sonar ping

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Develop and improve products. List of Partners vendors. Share Flipboard Email. Mary Bellis. Inventions Expert. Mary Bellis covered inventions and inventors for ThoughtCo for 18 years. She is known for her independent films and documentaries, including one about Alexander Graham Bell. Updated March 27, Featured Video. Cite this Article Format.

Bellis, Mary. The passive sonar equation is much simpler than the active sonar equation because passive sonars do not listen for echoes returning from a target. The term for target strength TS needed for active sonars is therefore irrelevant. The transmission loss TL appears only once, because only one-way transmissions are involved.

An example for the Acoustic Thermometry of Ocean Climate ATOC project illustrates the use of the passive sonar equation to compute the signal-to-noise ratio for one-way transmissions. Search for:. Home Science of Sound Sound What is sound? How do you characterize sounds? Amplitude Intensity Frequency Wavelength How are sounds made? What happens when sound pressures are large? Sound Movement How fast does sound travel? Why does sound get weaker as it travels? Sound Spreading Sound Absorption How does sound move?

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Disregard the rolling reverberations, and concentrate on catching the clear note of the returning echo from the target. At the instant it comes, note the reading on the scale. This is the range. This requires two changes: 1. When the light slit arrives at zero, an arc of red light will flash, indicating that the ping is going out. Following this there will usually be a series of little red flashes caused by the reverberations.

Then a good solid red flash will come at the same time that you hear the target echo. Read the range at the trailing edge of this flash.

This visual method involves two serious dangers. First, if the gain on the receiver-amplifier is set too high, you will get a confusing series of red flashes all over the dial from the reverberations.

Second, to flash the red light requires more current than to produce an echo in the headphones; so you are likely to get no flash at all from a weak echo. Why submarines do not echo-range continuously. If the conning officer requires a range more accurate than his periscope can give, he may order, "QB, get a single-ping range.

The time until the echo returns gives a measure of the target's range.