NARROW BAND RECEIVER

摘要

Embodiments of the invention relate to RF receiver technology and are particularly concerned with aspects of decoding data received at low data rates. In one arrangement, an RF receiver comprises a signal processor arranged to perform a method of decoding data contained within a signal that comprises a set of slots, at least one said slot comprising a preamble portion and a payload portion and being transmitted at a predetermined transmission frequency. The signal processor is arranged to perform a first process to derive timing data from the preamble portion and perform a second process to extract information from the payload portion, the second process being triggered from said timing data derived from the first process. The preamble portion comprises at least a first sequence of data and a second sequence of data, and the second sequence is the inverse of the first sequence. In preferred embodiments the first process comprises identifying a transition between said first and second sequences of data and deriving said timing data from the identified transition. The sequences of data can be embodied as a repeating pattern comprising at least two elements, e.g. first sequence can comprise 24 pairs of {1, 0} "dotting" and the second sequence can comprise 8 pairs of {0, 1} "anti- dotting". This transposition, or interface, between the first and second sequences is identified by components of the signal processor, and enables the receiver to identify bit timing associated with the preamble.