Electro-mechanical control means for space communication receiver

An electro-mechanical control means for a space communication receiver wherein the receiver includes a lens and a photodetector spaced along the optical axis of the lens, said photodetector providing a photodetector signal in response to light from the lens falling on the photodetector, said electro-mechanical control means including, in combination:

• (a) drive means for changing the distance between said lens and photodetector as measured along said optical axis to thereby shift the position of the focal point of radiation passing through said lens relative to said photodetector;
• (b) signal level detecting means for providing an output signal level in response to said photodetector signal;
• and
• (c) logic control means connected between said signal level detecting means and said drive means, said logic control means including self-focus subroutine means responsive to said output signal level to operate said drive means in a direction to move the focal point of said lens closer to said photodetector to increase the photodetector signal and thereby increase said output signal level, said self-focus subroutine means continuing to operate the drive means in the same direction until said output signal level starts to decrease at which point the drive means is operated in a reverse direction so that the drive means automatically focuses the radiation from the lens onto the photodetector by seeking the peak signal to provide a maximum output signal to noise ratio so long as said output signal level is below a given high threshold signal level defined within said logic control means.