The application discloses a
sine wave phase-locked loop circuit,
system and
oscilloscope realized by frequency pulling effect, wherein the
sine wave phase-locked loop circuit comprises an oscillator, a phase loop, an amplitude loop, an
analog multiplier and a
coupling network; the phase loop comprises a phase
discriminator, a first proportional integral circuit and a
voltage-controlled oscillator, and the amplitude loop comprises a detection circuit and a second proportional integral circuit; signals output by the phase loop and the amplitude loop are multiplied by the
analog multiplier, a waveform with adjusted frequency and amplitude is obtained, the waveform is coupled into the oscillator through the
coupling network, and the frequency of the oscillator is pulled. The
sine wave phase-locked loop circuit provided by the application can output a sine wave with very low
harmonic component, no error between a phase and an amplitude and preset values of a
microcontroller, can be used for designing a stable trigger circuit and an efficient
frequency spectrum analysis function for a virtual
oscilloscope, and greatly reduces cost. The application can be widely applied to the technical field of phase-locked loop circuits.