Direct-conversion receiver

)[1] The simplification of performing only a single frequency conversion reduces the basic circuit complexity but other issues arise, for instance, regarding dynamic range.

Although these and other technical challenges made this technique rather impractical around the time of its invention (1930s), current technology, and software radio in particular, have revived its use in certain areas including some consumer products.

The result is a demodulated output just as would be obtained from a superheterodyne receiver using synchronous detection (a product detector) following an intermediate frequency (IF) stage.

The proliferation of digital hardware, along with refinements in the analog components involved in the frequency conversion to baseband, has thus made this simpler topology practical in many applications.

The homodyne was developed in 1932 by a team of British scientists searching for a design to surpass the superheterodyne (two stage conversion model).

While the method has existed for several decades, it had been difficult to implement due largely to component tolerances, which must be of small variation for this type of circuit to function successfully.

The design principles can be extended to permit separation of adjacent channel broadcast signals whose sidebands may overlap the wanted transmission.

[2] The development of the integrated circuit and incorporation of complete phase-locked loop devices in low-cost IC packages made this design widely accepted.