A transmit pulser includes an H-bridge of four transistors. First and second
transistors
of the H-bridge connect with a first electrode of a transducer element, and third
and fourth transistors of the H-bridge connect with a second electrode of the transducer
element. A differential receive amplifier connects with the first and third transistors.
First and second diode clamps connect with the first and third transistors, respectively,
and the inputs to the differential receive amplifier. The second and fourth transistors
connect to a same power or voltage source, imposing a same voltage in either a
forward or a reverse direction. By using matched transistor pairs (e.g. first and
third matched pair and second and fourth matched pair), symmetrical transmit waveforms
are generated. Symmetrical transmit waveforms allow for using phase inversion or
phase differences between transmit waveforms for imaging, such as for harmonic
imaging of tissue. The spectral content of symmetrical waveforms is narrower or
includes less harmonic information.
