Importance

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Abstract

A cordless, battery-operated telephone of relatively low power consumption suitable to operate in license-exempt spectrum and which may employ an established communication protocol, such as the CT-2 communication protocol, is realized by providing a direct sequence spread spectrum (DSSS) modulator/spreader and demodulator/despreader in a battery-operated handset in connection with an intelligent CT-2 controller to which is added additional circuitry and functionality in the handset for acquiring, pulling-in and tracking, in both operational and low-power-consumption standby modes, a received DSSS signal from a base station unit. The additional functionality in the handset includes a PN phase discriminator with intelligent oversampling to deal with the time division duplex signals during synchronization, a second order delay lock loop for in-service mode tracking at a moderate loop iteration rate, and an extended-range discriminator and very narrow-band third-order delay lock loop for stand-by mode tracking at a very low loop iteration rate.

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First Claim