| 摘要 |
Improved transmission or storage of signals, such as high speed transmissions in subscriber loops of telecommunication systems, is facilitated by apparatus which includes an encoder (12) for encoding the input signal (I) before application to the transmission/storage medium (13) and a decoder (17) which decodes the signal received from the medium. The encoder comprises an analysis filter bank (21) which analyzes the input signal (I) into a plurality of subband signals (S0, S1, ...), each subband centered at a respective one of a corresponding plurality of frequencies; and a device (22) for combining a plurality of the interpolated subband signals to provide an encoded signal in which the interpolated subband signals occupy the same frequency band. The interpolated subband signals may be combined using QAM, CAP or DMT. The decoder (17) extracts the interpolated subband signals from a received encoded signal; and applies them to a synthesis filter bank, complementary and substantially inverse to the analysis filter, which processes the extracted interpolated subband signals (I') to produce a decoded signal corresponding to the input signal.
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