Can someone explain in very general terms how a wideband superhet radio scanner operates? We're talking about an older scanner (80's), which uses discrete circuity, etc. (no microprocessor) to quickly detect signals and also calculates and displays the frequency on a digital display. My main question is not how the signal is detected necessarily (single conversion to 2 MHz IF), but rather how the scanner knows which frequency it is receiving (i.e., so it can display the frequency on the LCD).