In a basic pulse-echo ultrasonic instrument, the component that produces the time base line is called:

In a basic pulse-echo ultrasonic instrument, the component that produces the time base line is called:

• A. Marker circuit
• B. Sweep circuit
• C. Pulser
• D. Receiver

Answer: (B)

The time axis on a pulse-echo display is set by the sweep circuit, which generates the time base line. This circuit produces a controlled ramp (or sawtooth) signal that drives the horizontal deflection of the display, so echoes that return after a given time appear at the corresponding position along the time axis. In practice, the longer the sweep, the deeper the maximum display range, since more time is available to collect echoes. The other components have different roles: the pulser sends the initial high-voltage pulse to excite the transducer; the receiver amplifies and processes the returning echoes; and a marker circuit may place reference indicators on the display but does not establish the continuous time base.

The time axis on a pulse-echo display is set by the sweep circuit, which generates the time base line. This circuit produces a controlled ramp (or sawtooth) signal that drives the horizontal deflection of the display, so echoes that return after a given time appear at the corresponding position along the time axis. In practice, the longer the sweep, the deeper the maximum display range, since more time is available to collect echoes.

The other components have different roles: the pulser sends the initial high-voltage pulse to excite the transducer; the receiver amplifies and processes the returning echoes; and a marker circuit may place reference indicators on the display but does not establish the continuous time base.