Voltage-controlled oscillator using a phase control loop for

Abstract

Voltage-controlled oscillator provided with a frequency-determining element and an oscillator loop having a phase-rotating network, in which the value of one or more elements depends on a control signal which is fed to a control input and with which the phase rotation and thereby the oscillator frequency can be changed. The oscillator is further provided with a phase control loop, at least comprising a phase-rotating network to the input of which the oscillator signal is fed, a phase detector to the two inputs of which the input signal and the output signal of said phase-rotating network are fed, and an amplifier which amplifies the output signal of the phase detector and feeds it to the control input of the phase-rotating network of the oscillator loop. The phase detector has an accurately known and temperature-independent input-output relation. The phase-rotating network of the phase control loop may be formed by the phase-rotating network of the oscillator loop (FIG. 2). Said oscillator loop may have at least two cascaded phase-rotating subnetworks, at least one of which has said phase control loop with phase detector and amplifier (FIGS. 3, 4, 5).