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Phase-locked loop evaluation board

Image Credit: Yue-Fang Kuo

Phase-locked loop evaluation board for GaAs HBT Voltage-Controlled Oscillator MMIC module

A phase-locked broadband GaAs HBT voltage controlled oscillator (VCO) module is design, fabricated and tested for the local oscillators in millimetre-wave astronomical heterodyne receivers. The configuration of the local oscillator module is based on the offset phase-locked loop (OPLL) scheme with frequency dividing in the feedback path. Employing closed-loop operation, the system can produce carrier frequencies with negligible reference spur. It can achieve 65% tuning range of VCO with bandwidth of 4GHz.