Abstract: A proximity measuring apparatus (70) comprises an interrogator (80) for generating an interrogation signal encoded with a reference signature code comprising concatenated codes and emitting it as interrogating radiation. It also incorporates a transponder (90) for receiving the interrogating radiation, demodulating it to extract its signature code and then remodulating it after a delay period to provide a signal for reemission as return radiation therefrom. The interrogator (80) receives return radiation at its antenna (260) and demodulates it to extract its signature code and then correlates the code with the reference code to determine mutual correlation thereof. The interrogator (80) incorporates a computer (290) for controlling a scan direction of the antenna (260) and for measuring time delay between emission of the interrogating radiation therefrom and receipt of corresponding return radiation.

Abstract: A method of fabricating a series-connected combination of two-terminal semiconductor devices on a common substrate comprising: forming a layer of high quality semiconductor material, 4, on the surface of a temporary substrate, 2 and 3, to provide active areas for the devices, forming first contact pattern conductors, 6, 9, 10, on the free surface of the high quality semiconductor layer to provide a separate first contact to this layer for each of the devices, bonding an insulating support substrate, 12, to the first contact pattern, removing the temporary substrate, forming second contact pattern conductors, 17, 18, 19, on the other surface of the high quality layer to provide a separate second contact to this layer for each of the devices, removing regions, 8, of the high quality layer separating the conductors of a pattern at any stage after beginning formation of the first contact pattern in order to define the device active areas so that parts of the first contact pattern are exposed when both the tempora