1. Beam former In a transducer with multi-element solid state crystals, the beam is focused and steered by exciting each of the elements at a different time so that the resulting sound wave coming from each crystal will arrive at the intended focal point simultaneously. In case A, the beam is being focused and steered to the left. Note that the distance from the focal point to element 1 of the transducer is shorter than the distance from the focal point to element 4. This means that in order for the waves generated by each element to arrive at the focal point simultaneously, element 4 must be excited before elements 1, 2, and 3. Likewise, in case B, the focal point is to the right, so the elements of the transducer must be excited in the reverse order. This process of phasing the firing of elements is "beam formation."
2. Beam Former In this case, it is easy to see that the echo returning from point A encounters element 1 before it encounters element 4. Thus, the signals coming into the ultrasound scanner from the various elements must be delayed so that they all "arrive" at the same moment. The signals from each element are summed together to form the ultrasound signal that is subsequently processed by the rest of the ultrasound instrument.