Low-noise digitally tunable phase-locked loop frequency generator

摘要: A variable-frequency main oscillator of digitally tunable high output frequency f is controlled by the integrated voltage a phase discriminator receiving on one hand relatively low comparison and other matching feedback stepped down from division or heterodyning with an auxiliary H same order magnitude ancillary oscillator, difference D =f -f fed to delivering corrective voltage, independent that emitted through filter network, control input oscillator. pair selectors varying and/or enable be adjusted in coarse fine tuning steps, adjustments being also applied limit excursions . In minimize shifts due changes setting fine-tuning selector, digital command generated selector converted into analog compensating subtracted discriminator.