A new digitally controlled time-gain compensation (TGC) amplifier for
ultrasonic scanners has been developed. The TGC amplifier features low
-noise, 40 dB compensation gain and can perform full customizing of th
e slope profile, thus permitting adjustable compensation for different
frequency transducers and allowing particular areas of interest to be
enhanced. The TGC is based on a specialized low-noise, voltage-contro
llable amplifier, an 8 bit digital-to-analogue converter, and a high-d
ensity 'in-system programmable' logical device. The simple design make
s it possible to use the amplifier as a stand-alone unit or to incorpo
rate it into existing ultrasonic equipment.