Sinclair Research Limited

Shaye Communications Limited

Michael R Pye

Stephen A Williams

An antenna system for portable electronic apparatus, particularly for the handset of a cordless telephone system, and comprising two antenna, a first (shown) mounted on a flap (2) and comprising a groundplane 5 and active monopole 4 fed by a coaxial feed 6 from electronic circuitry (not shown) in the main section of the handset 1. The flap is pivotally connected to the main section of the housing 1, and is folded down against the main section when not in use. Another similar antenna is fitted in the main section, and both antennae are connected to the transceiver circuitry via the same node. The two antennae are specially designed so as to introduce deliberate mismatch so as to provide an effective switching system between the two antenna without the need for separate circuit elements.

High performance antenna for hand-held and portable equipment

A Class B push-pull amplifier designed for use at low supply voltages (e.g. 1 to 2 volts) wherein complementary push-pull output transistors T.sub.3, T.sub.4 are biased by a biasing chain consisting of resistor R.sub.1, transistor T.sub.1, resistor R.sub.2, transistor T.sub.2, resistor R.sub.3, with the signal to the bases of T.sub.3, T.sub.4 being supplied from opposite ends of R.sub.2. The value of R.sub.2 is twice that of R.sub.1 and R.sub.3. The circuit is preferably used in a bridge configuration with a second similar amplifier set at unity gain driven from the first amplifier. It may be used to power the loudspeaker of a miniature radio receiver.

Growing community of inventors

Winchester, United Kingdom

Michael R Pye