Which system control on Doppler adjusts the PRF?

Which system control on Doppler adjusts the PRF?

• A. Dynamic range
• B. Packet size
• C. Ensemble length
• D. Spectral velocity scale

Answer: (D)

PRF establishes how often pulses are sent and sets the Nyquist limit for Doppler shifts—the maximum velocity you can display without aliasing. The spectral velocity scale is the control that adjusts the displayed velocity range, effectively tuning the PRF used for the spectral display. Turning up the velocity scale raises the Nyquist limit, allowing higher Doppler shifts to be shown without aliasing; turning it down lowers the limit and can bring higher velocities into aliasing or out of range. Dynamic range changes how wide a range of amplitudes is shown on the spectrum, not the timing of pulses. Ensemble length affects how many pulses are averaged to improve signal quality, not how often pulses are transmitted. Packet size relates to data transfer and storage, not Doppler timing. So, adjusting the spectral velocity scale directly influences the PRF setting used for the spectral display.

PRF establishes how often pulses are sent and sets the Nyquist limit for Doppler shifts—the maximum velocity you can display without aliasing. The spectral velocity scale is the control that adjusts the displayed velocity range, effectively tuning the PRF used for the spectral display. Turning up the velocity scale raises the Nyquist limit, allowing higher Doppler shifts to be shown without aliasing; turning it down lowers the limit and can bring higher velocities into aliasing or out of range. Dynamic range changes how wide a range of amplitudes is shown on the spectrum, not the timing of pulses. Ensemble length affects how many pulses are averaged to improve signal quality, not how often pulses are transmitted. Packet size relates to data transfer and storage, not Doppler timing. So, adjusting the spectral velocity scale directly influences the PRF setting used for the spectral display.