A heterodyne receiving circuit for a digital communication system
including a first band pass filter receiving a signal from an antenna, an
amplifying circuit and a second narrow band pass filter for selecting one
particular channel within a band of frequencies. The two filters are
carried out with integrated BAW-type tunable resonators which can be
adjusted, respectively, by a first electrical signal and a second
electrical signal generated by two PLL-type frequency control loops. The
second frequency control loop has a variable division factor for the
purpose of selecting one particular channel within said band of
frequencies. In addition, the receiving circuit includes a mixer for
mixing the signal generated at the output of said second filter with a
local oscillation frequency in order to produce an intermediate
frequency. The division factor is controlled by a digital processing of
the intermediate frequency.