GB531765A - Scanning-wave generator synchronizing system - Google Patents

Abstract

531,765. Television scanning wave generator. HAZELTINE CORPORATION. July 29, 1939, No. 22092. Convention date, Aug. 26, 1938. [Class 40 (v)] A television scanning system includes an oscillation generator synchronized by signal pulses so arranged that the generator is synchronized at the initiation of each trace-scanning period. In the apparatus shown, the television signal received by the aerial system 10, 11, Fig. 1, is passed through and to the several usual devices 12, 13, 14, 15, 16, 18. The synchronizing pulses f, Fig. 2, from the device 18 are injected into the oscillating. circuit of a valve 26 thereby producing pulses p controlling the valve 25, which in turn produces the periodic discharge of the condenser 21, periodically recharged through a pentode valve 22 or equivalent resistance. The valve system 25, 27 is so designed that the pulses p initiated by the leading edges of the synchronizing pulses f are independent of any irregularity in the width of these pulses and of a constant width corresponding to the retrace period. The saw-tooth pulse C derived from the condenser 21 and fed to the image reproducing device 15 has the usual apex S1 at the end of the trace period and in addition has also a sharp angle S2 ensuring accurate synchronization at the initiation of each trace period. Reference has been directed by the Comptroller to Specification 442,740.