(DAC) Part of the interface that converts digital numbers from the computer into analog (ordinary) voltages or currents. In ultrasound systems e.g., the high voltage transmit amplifiers that drive the transducers might be controlled by digital to analog converters (DACs) to shape the transmit pulses for better energy delivery to the transducer elements.

(ADC) A system that receives analog input data and produces digital values at its output. Analog to digital converters are used by the ultrasound scanner to convert the received signal into a format more compatible with the computer systems.
Ultrasound front-end-systems as well as many others sophisticated electronic systems use these analog signal processing components in connection with e.g., low-noise amplifier (LNA), and time gain compensation amplifier (TGC) as key elements in determining the overall system performance.

See also Digital to Analog Converter, and Digitization.

(TVR) The transmit voltage response is the level of the acoustic output referenced to one meter per one volt input.

See also Transmit Current Response, Doppler Velocity Signal, Analog Output Signal, and Digital to Analog Converter.

From ALOKA Co., Ltd.;
'A Platform for Digital, Pure-Beam Imaging The high-performance, ALOKA ProSound SSD-3500 utilizes advanced ProSound technologies including:
Fully digital beam former A wide dynamic range, 12-bit A/D converter Multi beam processing.
The SSD-3500 also helps you achieve more efficient examinations. Its ergonomic, user-friendly design enables you to customize the system according to your specific application needs.'

Digital systems use discrete numerical values or non-numeric symbols for input, processing, transmission, storage, or display rather than being composed of variable voltage, acoustic field or electromagnetic field.

See also Digital Imaging and Communications in Medicine and Analog to Digital Converter.