Decoding arrangements for synchronous receivers

In a decoding arrangement for decoding a transmission including batches of words, each batch comprising a respective synchronisation word followed by a plurality of code words, the arrangement comprising:

• receiver means for receiving said transmission;
• power control means for controlling supply of power to said receiver means;
• transmission detection means operative to detect receipt of said transmission by said receiver means;
• synchronisation word detection means operative to detect one of said synchronisation words;
• address detection means operative to detect an address word included in one of said pluralities of code words;
• and
• synchronisation-control means operative alternately to activate and deactivate said power control means respectively to enable and inhibit reception of said transmission by said receiver means so that reception is enabled at a predetermined time within each batch to allow said address detection means to detect said address word at said predetermined time;
• the improvement wherein:
• said synchronisation-control means includes a clock and is responsive to detection by said synchronisation word detection means of a single one of said synchronisation words to put said clock into word synchronisation with said transmission, and to inhibit said synchronisation word detection means from detecting any further synchronisation words in the same transmission;
• said synchronisation-control means is operative to derive each of said predetermined times at which reception is enabled from the time at which said single synchronisation word was detected by said synchronisation word detection means;
• and
• said synchronisation-control means is responsive to an indication by said transmission detection means that said transmission is no longer being received by said receiver means to put said decoding arrangement into a condition ready to receive another said transmission.