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High voltage amplifier chip11/26/2022 ![]() Techniques on harmonic suppression in the receivers are widely discussed in literature. Harmonic suppression techniques can be applied in both the transmitter and the receiver. Although simple and power efficient, the digital pulsers reported in contain an HD2 of −28 dBc, which is not suitable for THI. Most of today’s commercial medical ultrasound machines use HV digital square-wave pulsers (unipolar or bipolar) as the transmitters. In particular, the desired HD2 for THI is lower than −40 dBc for a sinusoidal signal of a few megahertz, with a load of 300 pF//100 Ω to emulate the transducer. To obtain good imaging quality using THI, it is thus crucial to minimize the harmonics generated from the ultrasonic systems including both the transmitter and the receiver. In THI, the ultrasonic energy is transmitted in a fundamental frequency, and an image is formed based on the second-order harmonic distortion (HD2) of the received signal, which is generated by the inherent nonlinearity of the body tissue. Moreover, to enhance the imaging quality, new imaging techniques, such as tissue harmonic imaging (THI), have been developed to provide images of better quality and contrast as compared with conventional ultrasound techniques. This HV signal swing is beyond the breakdown voltage of the devices in most existing HV CMOS processes. The target of this brief is to support the high end of the signal swing required in B-mode up to 180 V pp. First of all, the transmitter needs to be capable of generating HV signals to ensure the penetration depth of ultrasonic signals. In an ultrasound system, the transmitter that generates HV signals to excite a transducer is one of the most critical components in the entire ultrasonic diagnostic system. ![]()
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