freqency conversion

Hi all, I'm making a custom application and I need a source for a device that takes 300mA - 48VAC at 50 Hz to power. I can easily get the 48V, but how can I get it to 50 Hz? All I've got so far is just trying to rectify it and then using a function generator, but is there another way that wont...

Hi, I am new to RF-mixers, and i read that RF mixers should maintain the amplitude and phase relationship from the RF-input signal (Linearity). Do I use a wrong type of mixer, ore are there other ways of doing this. I can not get phase alignment. If anyone can enlighten me on this subject, I...