A programmable time-gain-compensation (TGC) amplifier for medical ultrasonic echo signal processing

In this paper, a programmable time-gain-compensation (TGC) amplifier dedicated to medical ultrasonic imaging systems is presented. This amplifier is composed of a true-logarithmic amplifier (TLA) and control circuitry. By using this amplifier, the early-returned strong echo signals from the near field tissue are less amplified, and the late-returned weak echo signals from the far field tissue are largely amplified. This amplifier is capable of handling echo signals with 80 dB input dynamic range (10¿V to 100mV). The embedded logarithmic amplification function can compress the large input signal dynamic range into a smaller output dynamic range, which benefits the further signal processing. Besides, the whole TGC amplifier can be flexibly programmed to meet the requirements of gain and timing for the actual conditions of ultrasonic-imaging diagnostic.