US Patent No. 10,868,548

PLL DEVICE


Patent No. 10,868,548
Issue Date December 15, 2020
Title Pll Device
Inventorship Tsukasa Kobata, Saitama (JP)
Kazuo Akaike, Saitama (JP)
Assignee NIHON DEMPA KOGYO CO., LTD., Tokyo (JP)

Claim of US Patent No. 10,868,548

1. A PLL device comprising:a voltage control oscillation unit that oscillates an output signal in an analog form which has a frequency corresponding to a control voltage;
an analog/digital converter that converts the output signal or a frequency division signal obtained by dividing the output signal by a preset dividing number as a feedback signal into a digital feedback signal;
a quadrature demodulation unit that quadrature-demodulates the digital feedback signal to obtain an in-phase component that is an I component and a quadrature-phase component that is a Q component;
a comparison signal output unit that outputs an I component and a Q component of a digital comparison signal, the digital comparison signal having a set frequency of the output signal when the feedback signal is the output signal and having a frequency obtained by dividing the set frequency by the dividing number when the feedback signal is the frequency division signal;
a phase difference detection unit that obtains a phase difference between the digital feedback signal and the digital comparison signal based on the I component and the Q component of the digital feedback signal and the I component and the Q component of the digital comparison signal;
a loop filter that outputs a control voltage value corresponding to the phase difference obtained at the phase difference detection unit; and
a digital/analog converter that performs a digital-to-analog conversion on the control voltage value obtained at the loop filter and supplies an analog-converted value as a control voltage to the voltage control oscillation unit.