An 18 Channel, Phase-Matched, Single-Conversion Upconverter from 30MHz to L-Band

An 18 channel, phase-matched Upconverter has been developed by Marconi Space and Defence Systems Ltd. The Upconverter translates the 18 separate IF signals from 30MHz to L-Band while maintaining the channel phase and amplitude relationships. To ease phase tracking problems a sub-harmonically pumped mixer is used. This provides an effective LO rejection greater than 50dB and thus enables a single conversion to be used without high-order filtering. The applications and limitations of sub-harmonically pumped mixing schemes applied to upconverters are discussed.