Technophone Limited

Simon Philip O'Neill

N E Martensson

Alan Charles Grimmett

Roger Wilkins

A cellular radio telephone system comprises a mobile cellular telephone (1) adapted to have a hand portable telephone (2) containing a number assignment module, i.e. a NAM (7), removably connected thereto. The mobile telephone (1) has a microprocessor (4) which can access the information stored in the NAM (7) of the hand portable telephone (2) either directly or via a memory 16 whereby the mobile automatically assumes the telephone number of the hand portable telephone when the two telephones are connected together. Hence a subscriber need only have a single billing account for both telephones. Also, the same mobile telephone may be used as a host at different times by any number of subscribers having their own hand portable telephones. Each subscriber will be able to receive his own calls and the charges for using the system can be levied to the appropriate subscriber's account.

Host radio telephone to directly access a handset NAM through a

A levelling control arrangement for an RF transmitter circuit which additionally compensates for filter ripple, i.e. frequency dependant power variations caused by the filter disposed between a transmitter amplifier and an antenna. The forward and reflected power is sampled by a dual directional coupler between the amplifier and the filter. Signals V.sub.fwd and V.sub.rev are thus obtained indicative of the forward and reflected power levels respectively. The reflected signal V.sub.rev is subtracted from the forward signal V.sub.fwd at comparator and the difference signal V.sub.diff is compared with a reference signal Vref at comparator to produce a signal V.sub.c which is used to control the gain of the amplifier in such manner that the power developed by the amplifier increases as the signal V.sub.rev increases and vice versa. To protect against excessive reflected power levels a limiter may be included which causes the power developed by the amplifier to be reduced only if V.sub.rev exceeds a pre-set threshold.

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Bracknell, United Kingdom

Simon Philip O'Neill