Abstract: Using the interferometer technique, a laser light beam is split into two beams one of which is directed along a first light path having a fixed length and the other is directed along a second light path having a variable length. The length of the second light path is varied by a mirror assembly mounted on a piezoelectric block, the length of which is controlled by a modulation signal corresponding to the desired information signal. When the two light beams are recombined at the ends of the first and the second light paths, the varying of the length of the second light path results in a variable phase of the second light beam with respect to the first light beam that is modulation signal dependent at the precise point of recombination of the first and second light beams. The effect of the variable phase combination of the first and second light beams is a vectorial phase addition, the resultant laser light beam after this vectorial combination being intensity (amplitude) modulated by the modulation signal.

Abstract: A peak radiated energy locator includes a plurality of broadband antennas mounted on a mast positioned between the radiating device and a calibrated antenna located to receive the radiated energy. The vertical angle at which peak radiated energy occurs is determined by establishing the broadband antenna receiving energy at a level that exceeds the levels of all the other broadband antennas and providing the vertical angle corresponding to the height of that antenna. The mast and broadband antennas are then removed, the calibrated antenna is positioned at a height corresponding to the determined vertical angle and an accurate measurement of the peak radiated energy is made.

Abstract: Testing apparatus in accordance with the invention generates a composite video signal for a CRT which produces a scanning line raster on the video screen thereof clearly displaying the spot size and line focus of the scanning electron beam generating such raster. The display consists of a single scanning test line of high luminance, or white, within an intermediate low luminance or black portion of an otherwise white scanning line raster. The test line is segmented, with black gaps at several discrete locations thereon, each gap being approximately three times the width of the scanning beam spot. Centered within each such gap is a region of high luminance, or white, of a width approximately that of the beam spot. The line focus and spot size of the smallest possible picture element is thereby accurately displayed and so can be measured on the video screen, enabling adjustment of the focussing components for optimum focus.