process for stabilizing the frequency of a local oscillator in an automatic radioricevitori impieganti an oscillator

摘要

a process is described for stabilizing the frequency of a local oscillator in sintonizzabili and wide band, used in receivers of a bridge digital radio microwave.a microprocessor, is proposed for the control of the normal operation.the voltage of the control law in cycles of vco inserted in a pll which reconstructs an intermediate frequency carrier used for demodulare consistently the signal received.the voltage read is compared with a reference value good, make a signal error which controls a diode varicap framework for the correction of the line.each reading the value that can be modified on the basis of information provided by a temperature sensor in thermal, erasing the effect of temperature on reference (fig. 2).