Importance

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Abstract

Methods and apparatus for digital cordless telephone systems are preferably implemented in an integrated circuit chip set having one or more chips, adapted to receive a voice signal, for converting the voice signal into a digital signal of a desired form, for converting the digital signal into an analog signal and for modifying the frequency of the analog signal, for up converting during transmission the frequency of the analog signal from an intermediate frequency to a desired radio frequency and for down converting during reception from a selected radio frequency to the intermediate frequency and for amplifying the radio frequency signal during transmission and for switching the antenna between the transmit and receive paths. It is preferred for the chip set to include a base chip, an intermediate frequency chip, a radio frequency chip and an amplifier chip. It is preferred to also provide a synthesizer integrated circuit chip for generating carrier select signals to be used by the radio frequency chip in selecting desired carrier frequencies. The invention also includes a frequency translation scheme to be utilized in conjunction with the various chips. Utilization of this scheme serves to reduce spurious noise as well as to suppress transmit signals during receive operations. The invention also includes various sensors for adjusting the level of the signal to be transmitted and for adjusting the level of the signal received at the antenna.

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First Claim