Patent ID: 6415001
Filing Date: 2002-07-02
Classification: H03D,H04B

Abstract:
A communication system for communicating RF signals at any one of a plurality of communication standards through a common antenna, each communication standard having a unique transmit band, receive band, and a common data rate, the communication system comprising:a transmitting unit having a transmit RF information signal output, the transmitting unit having a modulator for transforming a transmit baseband information signal into a modulated transmit IF information signal and an upconverter for upconverting the transmit IF information signal into a transmit RF information signal; a receiving unit having a receive RF information signal input, the receiving unit having a first downconverter for downconverting a receive RF information signal to a first receive IF information signal, a second downconverter for downconverting the first receive IF information signal to a second receive IF information signal, an analog-to-digital converter for converting the second receive IF information signal to a receive digital information signal, and a digital signal processor for processing the receive digital information signal; and an antenna coupled to the transmit RF information signal output and the receive RF information signal input for transmitting and receiving RF information signals; wherein the digital signal processor uses a processing clock greater than or equal to about four times the data rate, the analog-to-digital converter operates at a sample rate selected such that no odd-order harmonic of one fourth of the sample rate substantially coincides with any harmonic of the processing clock, and the second IF carrier frequency for the second receive IF information signal is selected to be an odd-order harmonic of one fourth of the sample rate.