为了实现较高的电容检测范围,传统的采用SAR ADC的开关电容(Switched capacitor,SC)的电容数字转换器(Capacitance to digital converter,CDC)使用高压供电提高输出摆幅,而其为了保证噪声性能又采用大电流驱动,所以显著增加了系统功耗...为了实现较高的电容检测范围,传统的采用SAR ADC的开关电容(Switched capacitor,SC)的电容数字转换器(Capacitance to digital converter,CDC)使用高压供电提高输出摆幅,而其为了保证噪声性能又采用大电流驱动,所以显著增加了系统功耗。为了解决以上问题,提出了一种基于数字放大器的电容数字转换器,将CDAC阵列作为模拟输出承担高压。仅对CDAC阵列与传感电容采用高压(5 V)驱动,而其余部分仍采用低压(1 V)供电,使得CDC在达到高动态范围与高灵敏度的同时保持低功耗、低噪声。此外,针对噪声的优化,本文一方面通过在数字放大器内加入积分环路实现SAR ADC的一阶噪声整形,降低了系统的量化噪声,提高了CDC的有效位数;另一方面通过引入有源噪声抵消(Active noise cancellation technology,ANC)技术,降低了系统的混叠噪声,提高了系统的信噪比。展开更多
现在市面上出售的DolbyDigital(杜比数字)放大器越来越多,而且新机种的价格也不停地在下降,中低价位的杜比数字放大器也就渐渐成为中高档家庭影院系统的首选。品种多了,也就面临着如何进行选择的问题,因此在这个专题中,我们将目前市面...现在市面上出售的DolbyDigital(杜比数字)放大器越来越多,而且新机种的价格也不停地在下降,中低价位的杜比数字放大器也就渐渐成为中高档家庭影院系统的首选。品种多了,也就面临着如何进行选择的问题,因此在这个专题中,我们将目前市面上流行的售价在万元左右的几款合并式Dolby Digital AV接收机集中到一起,进行了一次较详尽的评介及音效对比。展开更多
In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock...In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference.The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle.The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface.In the implementation of digital lock-in amplifier,a new routine which warranted the exactly matching of the reference phase to signal phase was proposed.The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal.The non linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degrees.The application of the software demodulation in the signal detection of micro-electro-mechanical-system(MEMS)device is a new attempt,and it shows the prospective for a high-performance application.展开更多
文摘现在市面上出售的DolbyDigital(杜比数字)放大器越来越多,而且新机种的价格也不停地在下降,中低价位的杜比数字放大器也就渐渐成为中高档家庭影院系统的首选。品种多了,也就面临着如何进行选择的问题,因此在这个专题中,我们将目前市面上流行的售价在万元左右的几款合并式Dolby Digital AV接收机集中到一起,进行了一次较详尽的评介及音效对比。
基金The National Natural Science Foundation ofChina(No.60402003)The National High Technology Research and Development Pro-gram of China(863Program)(No.2002AA745120)
文摘In the novel prototype of micro-gyroscope structure,the new configured capacitance sensing scheme for the micro gyroscope was analyzed and the virtual instrument based detection scheme was implemented.The digital lock-in amplifier was employed in the capacitance detection to restrain the noise interference.The capacitance analysis shows that 1 fF capacitance variation corresponds to 0.1 degree of the turn angle.The differential capacitance bridge and the charge integral amplifier were used as the front signal input interface.In the implementation of digital lock-in amplifier,a new routine which warranted the exactly matching of the reference phase to signal phase was proposed.The result of the experiment shows that digital lock-in amplifier can greatly eliminate the noise in the output signal.The non linearity of the turn angle output is 2.3% and the minimum resolution of turn angle is 0.04 degrees.The application of the software demodulation in the signal detection of micro-electro-mechanical-system(MEMS)device is a new attempt,and it shows the prospective for a high-performance application.
