How could I make an quadrature signal or combiner?

Dear all,

I design a quadrature LO input and IF quadrature combiner down-conversion mixer now. However, I don't know how could I create them? I have tried to use some model in rfLib. It has BB_shifter_spillter and BB_shifter_combiner. However, the 4 output will provide different voltage swing even the phase in quadrature. Could anyone teach me?

Thanks

wccheng

basically a broad side coupler ( hybrid coupler) having 90 wave length will give 90 phase shift

It depends. If IF is baseband then typically these signals are generated with DACs. If the IF signal is not baseband you can create 90° splitter with polyphase filters.

Are you designing an image reject mixer? What is your frequency and bandwidth of your LO and IF?

That will determine what method is best.

Yoda