| 摘要 |
<p>A transducer (10) emits an ultrasonic RF pulse. This pulse interacts with a reflector or scatterer from the moving target where a part of the wave is reflected. The ultrasonic RF pulses are generated in a transmitter (12). The output from the transducer is an electrical RF pulse signal which is applied to a receiver (14). The echo signals from the receiver are applied to a pre-processor (20) which includes moving target indicator rejection circuits thereby reducing clutter and noise in the signals. Separate samplers (26), (28) and (30)-(32) are used for each butterfly line. Each butterfly line corresponds to a distinct linear velocity. The criterion that a signal corresponding to the returns should be equal in amplitude at all points along the correct trajectory may be used for envelope and RF signals.</p> |
