The transmitter (see also projector) is the component of the ultrasound machine that creates the impulses sent to the transducer to generate the sound waves. Also called the pulser.

See also Transmit Voltage Response and Transmit Current Response.

B-scan comined with D-scan (D=Depth) is used to avoid image inhomogeneity. Different transmitter signals for each depth are applied and prefiltered pseudoinversely according to the transfer properties of the covering tissue. Pulse compression techniques with nonlinearly frequency modulated signals are used to gain the required energy for inverse filtering.
D-scan is a modified C-scan used in nondestructive testing with the display of amplitudes. In the 2D graphical presentation, time of flight values are displayed in the top view on a test surface.

See also A-Scan, B-Scan and C-Scan.

An omnidirectional transducer transmits or receives ultrasound waves in or from any direction with 360 degrees receiving capability.

See also Transmitter, and Receiver.

Piezo means pressure, so piezoelectric means that pressure is generated when electrical energy is applied to a quartz crystal. When electrical energy is applied to the face of the crystal, the shape of the crystal changes as a function of the polarity of the applied electrical energy. As the crystal expands and contracts it produces compressions and rarefactions, and creates sound waves. When this material is struck by sound waves it creates electrical currents.
Thus, a piezoelectric crystal can produce a pulse of mechanical energy (pressure pulse) by electrically exciting the crystal (transmitter), and they can produce a pulse of electrical energy by mechanically exciting the crystal (receiver). This ultrasound physics principle is called the piezoelectric effect (pressure electricity), which was discovered by Pierre and Jacques Curie in 1880, and is used to generate ultrasound waves. Instead of quartz crystals, piezoelectric ceramics such as barium titanate or lead zirconate titanate are also used, which are crystalline materials with similar piezoelectric properties.

See also Temporal Peak Intensity.

A projector (transmitter) converts the energy from the power amplifier (generator) into an acoustic pressure output. Projectors are usually driven near their resonance frequencies where they provide the highest acoustic output.