up converter and down converter
up converter and down converter are integrated assemblies that convert microwave signals to another frequency range for further processing. Generally, they are designed to produce an output signal frequency for a particular frequency band. RF upconverters are designed to convert microwave signals to a higher frequency range. By contrast, RF downconverters are designed to convert microwave signals to an intermediate frequency (IF). RF upconverters and RF downconverters that can upconvert or downconvert the frequency of a signal are also available.
RF upconverters and RF downconverters differ in terms of technology and form factor. There are two choices for technology: synthesized and crystal controlled. Synthesized devices use a use a synthesizer circuit (normally a PLL) to produce the desired frequency. Crystal-controlled devices use a crystal oscillator to produce the desired frequency. Generally, these products are more accurate than synthesized converters. In terms of form factor, RF upconverters and RF downconverters are available as integrated circuit (IC) chips and printed circuit boards (PCBs). Some devices are rack-mounted while others are designed to sit atop a table or desk.
Performance specifications for RF upconverters and RF downconverters include input frequency range and output frequency range; conversion gain, return loss, and noise figure (NF); power output and power consumption; number of channels; and operating temperature. Conversion gain is the net increase in power between the fundamental input signal and the desired output. It is calculated as the ratio (in dB) of the output power to the RF input power. Return loss is the amount of power that is lost to the load (output return loss) or the converter (input return loss). Noise figure (NF) is the ratio (in dB) of the signal-to-noise ratio at the input of the component and the signal-to-noise ratio measured at the output.
RF upconverters and RF downconverters must meet the communications standards of the communications networks in which they operate. Products may be designed for military or commercial communications applications, or used in radar systems and RF induction heating.