| 摘要 |
1,169,916. Synchronizing facsimile apparatus. XEROX CORP. 27 Sept., 1966 [1 Oct., 1965], No. 43082/66. Heading H2L. [Also in Division H4] In a facsimile system (see Division H4), facsimile signals derived in the transmitter by a document scanner are sent, together with scanning sync. pulses, over a telephone line to a remote receiver. At the receiver the separated sync. pulses (third waveform) are tested for coincidence with locally generated timing pulses (top waveform). An oscillator and frequency divider in the receiver generate driving pulses for a stepping motor which provides the scanning drive for the receiver printing stylus. If the sync. pulses do not lie within receiver-generated time gates (second waveform), the timing and driving pulse rates, and hence the scan rate, are increased to about 14% above normal. As soon as approximate synchronization is achieved (i.e. the sync. pulses fall within the time gates) the timing and driving pulse rates drop to about 3% above normal. When full synchronization is achieved, the pulse rates revert to normal. Failure of the receiver to become synchronized with the transmitter causes actuation of an alarm. Reference has been directed by the Comptroller to Specification 1,112,858. |
