Doppler Log and Emlog Flashcard

Front

What is the primary principle behind the Doppler log?

Back

Change in frequency of sound waves due to motion

Front

What frequency range is typically used in Doppler logs for underwater applications?

Back

20-30 kHz

Front

Which parameter does the Doppler log directly measure? Options: Absolute speed, Relative speed to water or ground, Wind speed, Water current speed

Back

Relative speed to water or ground

Front

In a Doppler log system, the term 'transducer' refers to the device that:

Back

Converts electrical signals to sound waves and vice versa

Front

A Doppler log measures speed over the ground by sending signals in which direction(s)?
Options: Forward, Downward, Aft, Forward and aft

Back

Downward

Front

What happens to the frequency of the signal when the vessel is moving toward the signal source?

Back

It increases

Front

Which physical principle does a Doppler log utilize to calculate speed?

Back

Doppler Effect

Front

Which part of the Doppler log system emits the ultrasonic signals? Options: Receiver, Sensor, Oscillator, Transducer

Back

Transducer

Front

What is a key limitation of a Doppler log when measuring speed over ground in shallow water?

Back

Signal scattering due to the seabed

Front

How does the angle of signal transmission affect accuracy in a Doppler log?

Back

Smaller angles increase accuracy