초록 ▼

A digital phase locked loop for correcting the phase of an output signal with respect to an input signal has a phase comparator for comparing the phases of the input signal and a feedback signal from a variable frequency oscillator. The output signal of the phase comparator representing the phase di

A digital phase locked loop for correcting the phase of an output signal with respect to an input signal has a phase comparator for comparing the phases of the input signal and a feedback signal from a variable frequency oscillator. The output signal of the phase comparator representing the phase difference is integrated in a low pass filter. The output of the low pass filter is supplied to a switch which alternately selects between the output of the low pass filter and a zero level signal from a zero generator. The output of the switch is supplied to the variable frequency oscillator. The output signal of the variable frequency oscillator is returned to the phase comparator, so that the phase of the output signal from the variable frequency oscillator is synchronized with the phase of the input signal.

대표청구항 ▼

A digital phase locked loop for correcting a phase of an output signal with respect to an input signal comprising: a variable frequency oscillating means; a phase comparator for comparing the phase of said input signal with the phase of an output signal from said variable frequency oscillating means

A digital phase locked loop for correcting a phase of an output signal with respect to an input signal comprising: a variable frequency oscillating means; a phase comparator for comparing the phase of said input signal with the phase of an output signal from said variable frequency oscillating means after every predetermined period; an integrator for integrating the output of said phase comparator; a first coefficient circuit for amplifying the output of said integrator; a second coefficient circuit for amplifying the output of said phase comparator; a first adder for adding the output of the first coefficient circuit and the output of the second coefficient circuit; a predetermined level generator; and a switch for selecting between the output of said first adder and the output of said predetermined level generator and for supplying the selected output to said variable frequency oscillating means, whereby said variable frequency oscillating means oscillates at a frequency proportional to the output of said switch.