ABSTRACT
The beam-forming techniques are used to acquire echo information from different parts of the imaged cross section by selection of the transducer array elements and manipulation of the relative timings of their transmit and receive signals. These yield echo sequences, which represent the B-mode image lines and define the spatial properties of the image. The transmit beam former controls the timing and the amplitude and shape of the signals sent to each element. These signals are generated digitally but are then converted to analog signals, that is, they become continuously variable signals. The echo signals generated at the transducer elements are generally too small in amplitude to be manipulated by the receive beam former and need to be amplified. In a B-mode image, the aim is to relate the display brightness to the strength of the reflection at each interface regardless of its depth.
