Alden Research Foundation

Gerald L Vano

A system for recording facsimile or teletype signals includes a switch connecting either signal to a graphic printer recording in raster format and means converting the teletype signals into raster format for recording on the same printer as are the facsimile signals.

Teletype compatible facsimile recorder

A facsimile recorder has a motor driving a scanning element and also generating recorder pulses occurring proportionally to the recorder scanning speed. A circuit for synchronizing the scanning motor with incoming framing pulses of a facsimile signal comprises a first dual data type flip flop with a first output, a first input receiving the framing pulses and a second input receiving the recorder pulses. The flip flop produces a gating pulse of duration corresponding to the interval between asynchronous occurrence of framing and recorder pulses which causes transmission of power to the recorder motor during the asynchronous interval. Consequently the motor speed and hence the period of the recorder pulses are varied in proportion to asynchronism until the framing and recorder pulses are coincident when the motor is synchronous with the framing pulses. Power is transmitted to the recorder motor at a particular frequency derived from a frequency standard. In addition to varying the time the power is transmitted the frequency of the power and hence the speed of the motor is varied by a second flip flop so as to reduce the time needed to bring the motor into synchronism with the received framing pulses.

Facsimile recorder framing circuit

A facsimile recorder having the capacity to record signals at different sweep rates and a circuit to distinguish noise from synchronization pulses so that the correct sweep rate will be utilized. The circuit includes a grounded timer switch which receives a start signal and opens to the voltage of the circuit and another switch which is opened to ground during the period between each of the phasing pulses. Two capacitors are arranged in parallel to receive a charge simultaneously while the switch is opened but a diode between them allows discharge of only the first of them when there is an interruption due to either noise or the next synchronization pulse. Since the rate of charge on the capacitors is substantially linear with respect to time, the charge on the second capacitor will remain at the highest level seen between the end of one pulse and a burst of noise or the next pulse if there is no noise. The voltage of the second capacitor is displayed to level detectors which signal a logic circuit in the recording equipment to direct the sweep rate of the recorder.

Facsimile recorder with sweep rate detection

A facsimile recorder for marking an electrosensitive web with a remote scanner signal including a periodically interrupted framing signal and a video signal comprises a scanning electrode and a cooperative electrode for marking the signals on the web during successive scans across the web. Scanning of the web is controlled by a framing circuit which compares the remote scanner framing signal with a recorder generated signal and uses the asynchronism of the two signals to control the scanning electrode until it frames the recorded scanner signal on the web. The recorder pulse generator comprises means sensing the voltage impressed through the web by the scanner signal. When the scan completes its crossing of the web the voltage drop across the scanning electrodes increases producing a recorder pulse which is delayed and applied to the framing circuit.

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Brockton, MA, United States of America

Gerald L Vano