British Telecommunications Public Limited Company

British Telecommunications Corporation

Michael T Hewitt

John W Ballance

Richard P Scott

A multipoint radio system has a single node which communicates with a plurality of outstations on one frequency. The outstations using a different single frequency to communicate with the node. The node controls the transmission frequency at the outstations, e.g. by transmitting error signals which adjust the set points of frequency control loops in the outstations. In a preferred embodiment the node allows for residual errors by adjusting the decision threshold of its regenerator to the outstation on transmission.

Frequency control for point to multipoint radio

In a time division multi-access communications system each burst in each slot commences with a preamble and the clocks used to control the sequence of operations are synchronized by means of these preambles. In particular the outstations control their transmissions to the node by timing pre-set delays from the receipt of the preamble. In a preferred embodiment the pre-set delays are adjusted by signals from the node so that bursts arrive at the node in correct sequence.

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Ipswich, United Kingdom

Michael T Hewitt