Superheterodyne Receiver

ABSTRACT

This paper discusses the basic design concepts of the Superheterodyne receiver in both single and double conversion forms, together with potential problems associated with each architecture.

This tutorial will describe a simple receiver architecture based on the super-heterodyne method of frequency translation.
A simple receiver could consist of an RF amplifier, band-pass filter and some form of demodulator. There is however a problem with this scheme in that the band-pass filter needs to be (1) Very narrow) and (2) tuneable.
We only want a single carrier and so the filter needs to be wide enough to allow the carrier (and it’s associated modulation side-bands) to pass through the filter whilst rejecting everything else. Secondly the narrow filter has to be tuneable over the frequencies of interest.
This is a very difficult requirement especially if the wanted signal is very high frequency.
A possible solution to this problem is to use the super-heterodyne receiver