A CMOS quadrature LC-tank voltage-controlled oscillator topology which uses a planar spiral trans- former as coupling elements has been implemented in mixed-signal and RF 1P6M 0.18 μm CMOS technology of SMIC. The measured phase noise is –125.7 dBc/Hz at an offset frequency of 1 MHz from the carrier of 4.6 GHz while the VCO core circuit draws only of 10 mW from a 1.8 V supply. The measured phase error is approximately 1.5 ° based on the time domain outputs and the output power is about –2 dBm. The VCO can cover the frequency range of 4.36–4.68 GHz. The tuning range is 320 MHz (7.0%) and the FOM is –189 dB.
针对堤坝坍塌,为避免伤亡和经济损失,需要对堤坝进行健康监控,及时提供预警;通过BOTDA(Brillouin optical time domain analysis)技术,设计并搭建堤坝实验平台,研究用分布式光纤传感器检测不同水流量下堤坝的形变;堤坝实验平台由恒流量装置和堤坝两部分组成,恒流量装置能精准的为堤坝提供所需的水流量,不同的水流量会给堤坝施加不同的压力,堤坝将在不同的水流量下产生相应的变形;将分布式光纤传感器埋入堤坝中,当堤坝发生形变,光纤会随着堤坝的变形而被拉伸,运用BOTDA技术对分布式光纤传感器进行测量分析,可得光纤的布里渊频移得数据,相应地反映了堤坝的变形;研究表明,光纤的布里渊频移能正确反映出堤坝形变,BOTDA技术应用于堤坝健康监控具有良好的监控预警效果。
A fully integrated cross-coupled LC tank voltage-controlled oscillator(LC-VCO) using transformer feedback is proposed to achieve a low phase noise and ultra-low-power design even at a supply below the threshold voltage. The ultra-low-power VCO is implemented in the mixed-signal and RF 1P6M 0.18-μm CMOS technology of SMIC. The measured phase noise is-125.3 dBc/Hz at an offset frequency of 1 MHz from a carrier of 2.433 GHz,while the VCO core circuit draws only 640μW from a 0.4-V supply.The designed VCO can cover a frequency range from 2.28 to 2.48 GHz.The tuning range of the circuit is 200 MHz(8.7%) and the FOM is-195.7 dB,which is suitable for an IEEE 802.11b receiver.
