A wide‐band push–push common‐collector Colpitts voltage‐controlled oscillator (VCO) usingimpedance peaking network and gain enhancing technique is proposed in this work.The impedance peaking network is introduced to increase the coupling factor ofthe differential inductor in the inductorcapacitor (LC) tank without sacrificing the quality factor. The impedancepeaking technique could guarantee the push–push VCO unconditionally oscillatingin a differential mode without degrading the phase noise performance. The gainenhancing technique employs an LC resonator in series with the emitterdegeneration resistor in the common‐collector amplifier in the VCO core toimprove the VCO oscillating amplitude and then improve the phase noiseperformance. The proposed VCO oscillates at around 20 GHz with >10.5%frequency tuning range from 18.9 to 21.4 GHz across temperature from −40 to125°C. The measured phase noise is lower than −107 dBc/Hz at 1 MHz offset acrossthe entire working temperature (−40 125°C). The whole VCO dissipates 45 mA under3.3 V power supply, and the typical figure of merit is around −177.92.
A grain moisture detection system is proposed in this paper, which is designed based on capacitive sensor and single chip microcomputer. The working principle of concentric capacitive sensor is introduced and the hardware circuits of system are described in details. The system has an intelligent controller internal, it can collect data, display data and determine whether to alarm when the data overreach threshold. The system is tested in practice and the measuring errors are analyzed, experiment results showed that the system has high measuring accuracy and good controlling capacity; it can meet the needs of moisture measuring.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.