Patent ID: 6215988
Filing Date: 2001-04-10
Classification: H04B

Abstract:
A multiband user terminal, comprising:a controller for outputting a BAND signal for specifying operation in at least one of a first frequency band or a second, higher frequency band;a single frequency synthesizer that is responsive to said BAND signal for outputting a local oscillator RF signal when operating in said first frequency band or said second frequency band; andan RF transceiver comprising a multiband receiver that receives RF signals in said first frequency band and in said second, higher frequency band, and a multiband transmitter that outputs a transmitted RF signal when operating in said first frequency band or in said second, higher frequency band, wherein said multiband transmitter comprisesa modulator that modulates said local oscillator RF signal in accordance with information to be transmitted and that outputs a modulated RF signal, wherein when operating in said first frequency band said local oscillator RF signal has a frequency that is equal to said transmitted RF signal, and wherein when operating in said second frequency band said local oscillator RF signal has a frequency that is equal to one half of said transmitted RF signal, and further comprising an upconversion mixer having a first input for receiving said modulated RF signal and a second input that receives said local oscillator RF signal, wherein said upconversion mixer upconverts said modulated RF signal, using said local oscillator RF signal, to have a frequency equal to said transmitted RF signal when operating in said second, higher frequency band,wherein said multiband receiver comprises a first receiver chain that operates in said first frequency band as a single conversion receiver having a downconversion mixer that is preceded by a first filter and that is followed by second filter, and further comprising a second receiver chain that operates in said second frequency band as a dual conversion superheterodyne receiver having a first downconversion mixer preceded by a first filter and followed by a second filter coupled to a second downconversion mixer followed by a third filter, wherein said downconversion mixer of said single conversion receiver is also said second downconversion mixer of said dual conversion superheterodyne receiver, and wherein said second filter of said single conversion receiver is also said third filter of said dual conversion superheterodyne receiver.