Editing Homodyne detection (section)

{{Short description|Sensor implementation technique}}
{{More citations needed|date=March 2015}}[[Image:HomodyneDetection2.png|thumb|200px|Optical homodyne detection]]
In [[electrical engineering]], '''homodyne detection''' is a method of extracting information encoded as [[modulation]] of the [[Phase modulation|phase]] and/or [[frequency modulation|frequency]] of an oscillating signal, by comparing that signal with a standard oscillation that would be identical to the signal if it carried null information.  "Homodyne" signifies a single frequency, in contrast to the dual frequencies employed in [[heterodyne detection]].

When applied to processing of the reflected signal in [[remote sensing]] for [[topography]], homodyne detection lacks the ability of heterodyne detection to determine the size of a static discontinuity in elevation between two locations.  (If there is a path between the two locations with smoothly changing elevation, then homodyne detection may in principle be able to track the signal phase along the path if sampling is dense enough). Homodyne detection is more readily applicable to [[velocity]] sensing.