Abstract: A data separator circuit for use in decoding single density encoded data retrieved from a floppy disc, the circuit comprising a phased lock loop edge aligning circuit in combination with logic circuitry for providing a first output of separated data and a second output of the separated clock signals. The separator circuit generates an approximately periodic data window which is held in phased alignment with respect to the approximately periodic clock signal, the data window being utilized to gate out, or separate out only the single density encoded data.

Abstract: In a facsimile system, rotation of a transmitter drum carrying a document is synchronized with the rotation of a receiver drum carrying a copy medium. Synchronization is achieved by rotating the transmitter drum at a substantially constant angular frequency while generating transmitter synchronizing pulses corresponding to that frequency and rotating the receiver drum at an initial angular frequency while generating receiver synchronizing pulses corresponding to the initial frequency where the initial frequency of the receiver drum differs substantially from the constant frequency of the transmitter drum. When partial coincidence between portions of a transmitter synchronizing pulse and the receiver drum synchronizing pulse is detected, the receiver drum is rotated at another frequency closer to the constant frequency of the transmitter drum.

Abstract: A facsimile receiver which may be acoustically coupled to a telephone transmission line comprises a preamplifier for amplifying frequency modulated signals. The output of the preamplifier is coupled to a demodulator comprising a single shot multivibrator and an average DC voltage detector connected to the output of the multivibrator. The output of the average DC voltage detector is applied to a stylus driver which controls the marking of a copy medium by a stylus. A signal quality detector and an indicator are coupled to the output of the preamplifier to provide an operator with an indication of poor signal reception quality.

Abstract: A facsimile transceiver comprising a document/copy receiving drum, a motor for rotation of the drum about the drum axis and a read/write head mounted for linear movement in a direction parallel with the drum axis. When the transceiver is operating in the receive mode, the copy medium having adhesive along at least one edge circumscribes the drum in a closed loop so as to eliminate the necessity for transmitter-receiver angular synchronizing signals which would otherwise be required for locating the copy margin adjacent the edge of the copy paper. After completion of a transmission, the copy medium is severed along a line so as to provide an appropriate margin for the copied information content. The copy medium may comprise a magazine having a plurality of sheets of a copy medium which form individual closed loops where one edge of each sheet overlaps with and is attached to the opposite edge of the sheet.

Abstract: A facsimile transceiver comprising a document/copy receiving drum, a motor for rotation of the drum about the drum axis and a read/write head mounted on a rotating shaft for linear movement in a direction parallel with the drum axis. When the transceiver is operating in the transmitting mode, the information of the original document is scanned by a reading fiber optic carried on the read/write head. Illumination of the document is provided by a light pipe or a plurality of fiber optics which substantially surround the reading fiber optic which extends from the base of a recess in an arcuate surface of the read/write head which rides on the document carried by the drum.

Abstract: In a facsimile transmission system, a transmitter comprises a read photodetector which scans a document for video content and a lead photodetector which scans the document in advance of the read photodetector. The output of the read photodetector is coupled to a modulator which generates signals for transmission to a facsimile receiver at a remote location. The output of the read photodetector and the lead photodetector are also coupled to timing circuitry which automatically initiates a fast scanning mode for the read and lead photodetectors after a predetermined time lapse without detection of a dark, information-bearing area on the document. The facsimile receiver which comprises a stylus for scanning a copy medium and a demodulator for controlling marking on the copy medium by the stylus also includes timing circuitry for automatically initiating a fast scanning mode after a predetermined lapse in time between received signals representing dark, information-bearing areas.