Takayuki Nakatani

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Digital polar transmitters are under development for multiband handset applications, but typically lead to excess Rx band noise (RxBN). In this paper, a technique to improve the RxBN of a digital polar transmitter is demonstrated. Linear phase FIR filters are applied to both envelope and phase signals, so that the RxBN becomes relatively insensitive to(More)
A polar transmitter driven by digital input signals for envelope and phase is demonstrated, using a switched output resonator to achieve multiband operation. A new digital pulse width modulation algorithm is also shown to partially suppress spurious signals associated with the digital input envelope signal. The transmitter consists of a current-mode class-D(More)
In an electrohydraulic total artificial heart developed at the National Cardiovascular Center (Osaka, Japan), two blood pumps are pushed alternatively by means of the bidirectional motion of a brushless DC motor for pump systole and diastole. Improvement in the dynamic response of the motor is very important to obtain better pump performance; this was(More)
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