DIRECT CONVERSION UP-CONVERTER FOR BROADBAND WIRELESS ACCESS EQUIPMENT

摘要

A direct conversion up-converter provides direct up-conversion of a modulated broadband intermediate frequency ("IF") signal, which is on the order of 5 to 50 MHz, to a modulated radio frequency ("RF") signal, which is on the order of 70 MHz to 60 GHz. The direct up-conversion does not use super-heterodyne mixing. The direct conversion up-converter includes a demodulator unit to demodulate the modulated IF signal into a real baseband signal component ("I") and an imaginary baseband signal component ("Q"). Each basedband signal component I and Q is then amplified and passed through a bandpass filter to remove high frequency noise. The filtered baseband signal I and Q are then modulated by a modulator unit into a modulated RF signal. The demodulator unit performs the demodulation with an oscillation frequency corresponding to the modulation frequency of the modulated IF signal. The modulator unit performs the modulation with a second oscillator frequency which corresponds to a desired modulation frequency of the modulated RF signal. The demodulator unit and the modulator unit are formed from a plurality of integrated circuits disposed on a signal circuit board.