Abstract: An optical sender or detector device with an envelope (U) whose light entrance and/or light exit surfaces are adapted to provide a desired radiating or receiving characteristic that is to be able to radiate directionally in two or more spatial directions or respectively to receive directionally from two or more spatial directions. The light entrance and/or light exit surfaces having reflecting curves (R 1, R 2) and lenticular curves (L 1, L 2).

Abstract: The invention relates to transducer electrodes for filters or delay lines using surface wave principles on piezoelectric substrates wherein parallel mounted electrodes have interdigital fingers extending toward the electrodes and wherein feeders for the fingers have widths of one half the wave length of the surface wave at the mean filter frequency so as to equalize and eliminate reflections in the device.

Abstract: Transducer electrodes for filters or delay lines using surface waves wherein the transducers are formed by interdigital conducting films formed on the surface of piezoelectric substrates and wherein the length of the interdigital electrode fingers vary and wherein all of the fingers on at least one side are attached to an enlarged metal area which has a width equivalent to the total width of all of the electrode fingers on this side.

Abstract: A television IF filter constructed in accordance with the surface wave principle comprises an input transducer and two output transducers constructed in interdigital form, the output transducers being arranged symmetrically with respect to the input transducers upon a piezo-electric substrate. An input transducer comprises a main section and a subsidiary section. The main and subsidiary sections are electrically and mechanically connected in parallel, the main section being tuned to the center of the television IF frequency and having a variable overlapping range of the transducer teeth corresponding to a function y = sin x/x. The resonant frequency of the subsidiary section is tuned in such a manner that a step in the filter curve at the sound frequency, looking like staircase is produced. The output transducers also have a main section and a subsidiary section, respectively, whose respective resonant frequencies are tuned to that of the input transducer section which is associated therewith.