Abstract: A flat screen display system uses a two-dimension surface acoustic wave ("SAW") scanning. The flat screen is made of a piezoelectric substrate coated with a layer of piezoluminophor powder. Four SAWs having two by two nonparallel directions are launched along the piezoelectric surface. The first of the two SAWs is pulsed and the third one has a constant amplitude. The fourth SAW is modulated by the information to be displayed. With respect to the modulated SAW, the pulsed SAWs are launched with a delay that is determined by the distance to be covered by the modulated SAW, for reaching the point which the current modulation corresponds to.

Abstract: The circuit comprises a surface acoustic wave device. On the substrate (32) f the surface acoustic wave device, are provided two pairs of input transducers (33, 34, 35, 36) connected, in parallel, to the input of the circuit. The transducers (33, 34, 35, 36) initiate surface acoustic waves corresponding to the signals applied on two pairs of paths (41, 42, 43, 44) ending at two pairs of reception transducers (37, 38, 39, 40). The outputs of the output transducers of the first pair (37, 38) are connected to the two inputs of a mixer (28) whose output yields the received digital signal. The outputs of the second pair of transducers (39, 40) are connected to the inputs of two limiters (26, 27) whose outputs are connected to the two inputs of a mixer (29) whose output yields the analog signal.

Abstract: A common channel charge transfer recursive filter has two delay lines, in which charges are transferred in opposite directions. Exchange bridges having two sections extend between the lines. Each section feeds a predetermined charge fraction to one of the two downstream electrodes with charges flowing from the two upstream electrodes. The charge transfer is controlled by a three-phase system (.phi.1, .phi.2, .phi.3). Split memory electrodes and the exchange bridges are connected to the first phase (.phi.1) bus. A transfer electrode is in each gap between an exchange bridge and a memory electrode and is connected to the second phase (.phi.2) bus. A second transfer electrode is connected to the third phase (.phi.3) bus. The gap between a memory electrode and the next exchange bridge is occupied by a transfer electrode connected to the second phase (.phi.2) bus and by a transfer electrode connected to the third phase (.phi.3) bus.

Abstract: A CTD recursive filter includes a single channel with two side-by-side CTD delay lines wherein charges are transferred in opposite directions. Each electrode of the first delay line forms a pair with a corresponding electrode of the second delay line. Each even pair of electrodes are separated from the next odd pair of electrodes by an even bridge electrode occupying the entire width of the channel. Each odd pair of electrodes are separated from the next even pair of electrodes by an odd bridge electrode also occupying the entire width of the channel. An electrode of the first line in an even pair and the electrode of the second line in the next odd pair have lengths the sum of which is a constant. An electrode of the first line in an odd pair and the electrode of the second line in the next even pair have lengths, the sum of which is equal to the constant. At each odd clock pulse, the odd bridge electrode charges are distributed to the closer even bridge electrodes.

Abstract: The surface elastic wave device is an integral part of an analog-digital converter with intermediate frequency conversion. It is comprised of the acoustical part of a 4-pole surface elastic wave oscillator, a surface elastic wave reflector with track shifting working as a filter assembly and comprising one supply track and several return tracks having different angular frequencies, the reflector operating as a plurality of filters, and output transducers overlapping the return tracks and connected to detectors producing the digital information. Many types of reflectors and output transducer assemblies are described. The invention is useful with analog-digital converters having medium access times.