The invention discloses an all digital frequency converting method and a device thereof, being easily realized for hardware. The method and the device are essentially used for sample rate convertion of rational number-times of
baseband signals and the convertion of the
baseband signals and the
intermediate frequency signals in digital communication. Under the coordination of control signals and enabling signals, the convertion of
signal sample rate can be finished and the convertion of the
baseband signals and the intermediate signals can be finished through the reasonable matching of variable integral number-times wave filtering and fraction-times interpolation. The
system of the invention essentially comprises a
frequency mixer, a
cascade connection integral
comb filter, a fraction-time interpolating device, a half-band filter, a
signal shaping filter, a power detection module and a control interface. The
configurable hardware implemented structure of the invention is applicable to a plurality of modulation methods, has the advantages of
low resource consumption and good portability, and is used for various
wireless communication systems such as multilevel
phase shift keying (MPSK), orthogonal frequency division
multiplex (OFDM),
direct sequence spread spectrum (DSSS) and
continuous phase modulation (CPM), etc.