Modulator and phase-locked loop circuit

The invention discloses a modulator and a phase-locked loop circuit. The modulator comprises a shifting unit and an arithmetic unit, the shift unit is controlled by an enable signal to be opened or closed, the shift unit receives an input signal and generates a first output signal, the operation unit is used for operating the first output signal to obtain a modulation signal, the operation unit comprises one or a plurality of connected n-bit accumulation modules, n is equal to m + k, m is the bit of the input signal, and m and k are integers greater than or equal to 1. According to the modulator and the phase-locked loop circuit, data loss, error accumulation and precision maintenance of subsequent digital filter division are achieved by increasing the number of bits of the accumulation module, lossless filtering is achieved through a simple digital filter, and compared with a traditional phase-locked loop circuit with a digital filter, the modulator and the phase-locked loop circuit have the advantages that