These devices are related to the frequency converters, but are usually based on a vector (I,Q) modulator to convert a signal from zero center frequency to some higher center frequency that can be from several MHz to the GHz range.  This converter will likely contain a local synthesized oscillator as well, permitting coherent or incoherent upconverstion – depending on the application.  We can develop these converters as part of a tightly integrated radio system or as a stand-alone system block for use in a modular RF system (e.g. satellite ground station, broadcast installation, etc.).