Term
| What are the 3 elements required to produce sound? |
|
Definition
| Source, medium, and reciever. |
|
|
Term
| What are the 2 types of looses sound suffers in water? |
|
Definition
| spreading and attenuation |
|
|
Term
| What is transmission loss? |
|
Definition
| The combination of spreading and attenuation. |
|
|
Term
| What are the 2 types of spreading? |
|
Definition
| Spherical and Cylindrical. |
|
|
Term
| What are the different types of attenuation. |
|
Definition
| Absorption and Scattering and Reverberation. |
|
|
Term
| What are the different types of Scattering and Reverberation? |
|
Definition
Volume(Marine life, bubbles, etc.),
Surface (Function of wind speed), and
Bottom Loss |
|
|
Term
| What are the 2 types of noise? |
|
Definition
|
|
Term
| What are some types of self noise? |
|
Definition
| Hull/Machinery Noise, Flow Noise, Cavitation. |
|
|
Term
| What are some types of ambient noise? |
|
Definition
| Hydrodynamic, Seismic, Biological, and Ocean Traffic (BOSH). |
|
|
Term
| What is Signal to Noise Ratio (SNR)? |
|
Definition
The ratio of the received echo from
the target to the noise produced by everything else. |
|
|
Term
| What is the Detection Threshold? |
|
Definition
The level, of received signal, required for an operator to
detect a target signal 50% of the time. |
|
|
Term
| Which sonar equation is this: SL - TL - NL + DI > DT? |
|
Definition
| The Passive Sonar Equation |
|
|
Term
|
Definition
A measure of the reflectivity of the
target to an active sonar signal. |
|
|
Term
| Which sonar equation is this: SL - 2TL + TS - NL + DI DT? |
|
Definition
| Active Sonar Equation; Ambient Noise Limited |
|
|
Term
| Which sonar equation is this: SL - 2TL + TS - RL DT ? |
|
Definition
| Active Sonar Equation; Reverberation Noise Limited. |
|
|
Term
| What is the Figure of Merit (FOM)? |
|
Definition
| the maximum allowable one-way transmission loss in passive sonar, and the maximum two-way transmission loss in active for a detection probability of 50%. |
|
|
Term
| What is the speed of sound in the ocean? |
|
Definition
|
|
Term
| What affects the Speed of Sound in Water? |
|
Definition
| Temperature, salinity, and pressure. |
|
|
Term
|
Definition
Rays will bend when passing
between two different mediums. (refraction) |
|
|
Term
| Which way does sound bend? |
|
Definition
towards the region
of slower speed (It is lazy). |
|
|
Term
| What are the different types of sound propagation? |
|
Definition
| Direct path, surface duct, bottom bounce, convergence zone, half channel, and sound channel. |
|
|
Term
| What kind of gradient is needed for sound channel conditions? and what is the advantage of this type of propagation? |
|
Definition
| Negative over Positive gradient; it gives the longest ranges. |
|
|
Term
| How do we obtain environmental data? |
|
Definition
XBT’s, Change depth (for a sub),
Satellite imagery / message traffic
(METOC support) Observe ship handling changes. |
|
|
