Patent ID: 7170956

Claim:
An apparatus for demodulating a digital input signal having a pre-assigned symbol rate by using a single sample clock signal; said pre-assigned symbol rate is selected from the group consisting of a plurality of symbol rates; said apparatus comprising: a Complex Mixer configured to down convert an input digital signal having said pre-assigned symbol rate signal from a carrier frequency to a baseband frequency; a Cascaded Integrated Comb (CIC) Decimator filter electrically communicating with said Complex Mixer, said CIC Decimator configured to perform a filtering-decimation operation to isolate a down converted digital signal having a pre-assigned symbol rate, and configured to output an Inphase (I) component and a Quadrature (Q) component of a CIC_output_signal having a CIC-shaped decimated spectrum; a Shaper filter electrically communicating with said (CIC) Decimator filter, said Shaper filter is configured to restore an original spectrum of said I and Q components of said CIC_output_signal having said CIC-shaped decimated spectrum; said Shaper filter configured to output I and Q components of a shaper_filter_output_signal, wherein said I component and said Q component of said shaper_filter_output_signal include a shaper_signal component having a restored original spectrum of said pre-assigned signal and include an adjacent shaper-signal component having a spectrum that is adjacent to said restored original spectrum of said pre-assigned signal; a CIC cutoff filter electrically communicating with said Shaper filter; said CIC cutoff filter configured to pass said shaper_signal component having said restored original spectrum of said pre-assigned signal; said CIC cutoff filter configured to pass a part of said adjacent signal having a spectrum part that is carved out by a frequency response function of said CIC cutoff filter; a Demodulator electrically communicating with said CIC cutoff filter; said Demodulator configured to demodulate and to extract a frequency component from said shaper_signal component having said restored original spectrum of said pre-assigned signal; a Coarse Frequency estimation block electrically communicating with said Demodulator; said Coarse Frequency estimation block configured to estimate a frequency offset between said pre-assigned carrier frequency and said frequency component of said shaper_signal component having said restored original spectrum of said pre-assigned signal; and a CIC tuner loop filter electrically communicating with said Coarse Frequency estimation block; said CIC tuner loop filter configured to insert said estimated by said Coarse Frequency estimation block frequency offset into a carrier loop in order to complete a carrier recovery of said pre-assigned input digital signal.