stage. In radio electronics
, an incoming or outgoing RF signal
goes through one or more stages altering its frequency
before it is finally heads to antenna
For example, if you are tuned to Wild FM at 89.7 MHz, in many FM receivers, the RF energy will be downconverted to about 10 MHz, before it hits the FM circuitry.
Microwave circuitry requires the signal to be upconverted over several stages to reach the high frequencies of the UHF band, 2 - 20 GHz.