Abstract: An optical recording, erasing and playback system. One or more functions in a conventional optical disc system are performed by one or more holographic optical elements (HOE). Exemplary of the functions performed by the HOE are collimation, beam shaping, combining of beams, and focusing. According to preferred embodiments, volume HOEs are utilized.

Abstract: To improve the serviceability, manufacturability and uptime for a computer file server a specially designed planar/riser card assembly is mounted on the computer chassis and includes a card cage structure in which a riser card is secured. Carried on the riser card are I/O card edge connector sockets into which all of the system I/O cards may be plugged. The riser card is hard connected into the system and itself has an edge connector portion. The system planar board is carried on a mounting plate which is screwed to an outer side of the cage structure. A socket connector carried on the planar board receives the edge connector portion of the riser card, thereby electrically coupling the planar board to the riser card. The riser serves as a wiring plane containing only the signals which the planar board would normally provide to the I/O cards through "on planar" connectors.

Abstract: A communication system for simultaneously transmitting data and audio signals via a conventional audio communications channel using perceptual coding techniques is disclosed. In a preferred embodiment, a first artificial neural network (NN) at an encoder monitors an audio channel to detect "opportunities" to insert the data signal such that the inserted signals are masked by the audio signal, as defined by the "perceptual entropy envelope" of the audio signal. Under the control of the first NN a data signal containing, for example, an ID or serial number, is encoded as one or more whitened direct sequence spread spectrum signals and/or a narrowband FSK data signal and transmitted at the time, frequency and level determined by the first NN such that the data signal is masked by the audio signal. The audio signal is combined with the spread spectrum and/or the FSK data signal(s) to form a composite signal, which is transmitted to one or more receiving locations via the audio channel.