What will NOT induce errors into a doppler sonar log?（）

单项选择题The microsecond unit of time is used in radar applications. The microsecond represents which of the following?（）.

A.one-millionth part of a second
B.one-thousandth part of a second
C.one-hundredth part of a second
D.one-tenth part of a second

单项选择题The minimum range at which a target can be detected is basically determined by which of the following?（）.

A.persistence
B.pulse repetition rate
C.pulse length
D.rotation rate

单项选择题The number of pulses of energy transmitted per second is call the（）.

A.carrier frequency
B.pulse repetition rate
C.pulse length
D.pulse repetition time

单项选择题The radar component that generates the radio-frequency energy in the form of short powerful pulses is which of the following?（）.

A.magnetron
B.receiver
C.indicator
D.modulator

单项选择题The radar component that produces the synchronizing signal and triggers the indicator sweep is which of the following?（）.

A.transmitter
B.antenna system
C.indicator
D.modulator