Abstract:
A transmultiplexer (202) is provided for transmultiplexing digitized signal samples (244) produced by a converter. The transmultiplexer (202) comprises a first Fourier transformer bank (304) configured to transform the digital signal samples (244) produced by the digitizer into frequency domain input signals (320). The transmultiplexer (202) also comprises a frequency domain shifter bank (306) configured to circularly shift the frequency domain input signals (320) to produce shifted signals (324). A frequency domain pre-filter bank (308) is configured to perform a first fast convolution with the shifted signals (324) and a first discrete Fourier transform of a first filtering function to produce filtered input signals (330), and a combining Fourier transformer (310) is configured to transform the filtered input signals (330) to produce output signals (348) containing a sample corresponding to a down-converted channel.