Improvements in or relating to apparatus for transforming electrical signals from one scanning standard to another

摘要

718,223. Cathode-ray tubes. COMPAGNIE POUR LA FABRICATION DES COMPTEURS ET MATERIEL D'USINES A GAZ. Aug. 28, 1952 [Aug. 29, 1951], No. 21636/52. Class 39(1) [Also in Group XL(c)] In an electrostatic recording and reproducing tube in which separate writing and reading beams scan an area of a continuously-moving charge storage target at different times, at different positions of the target and at different speeds, the target is an insulating layer on a metal support which, when bombarded by the high velocity writing beam forms a charge image by the phenomenon of bombardment induced conductivity. In the drawing 2 and 5 are the writing and reading guns which are scanned at different line speeds and at the same line positions over rotating drum 9 which gives the frame movement. The signalmodulated writing beam has an energy of about 10,000 volts, while the reading beam is of constant intensity and causes secondaries to be emitted from the target and collected on the anode of gun 5 to develop an output signal across impedance 8. Drum 9 is an earthed metal body coated preferably by evaporation with an insulating layer about one micron thick of Si O 2 or Mg F 2 . The writng and reading are both effected continuously, The arrangement may be used for changing the number of scanning lines in a television picture without changing frame frequency or synchronization or, if the drum is replaced by a rotating disc, may be used in a P.P. I. radar indicator. An auxiliary gun 10 producing slow flooding electrons may be used for completing the erasure of the charge image and/or for raising the potential level of the signals on the target. The evaporator(s) of the insulating layer on the target may also be included within tube envelope 1. Specification 667,928 is referred to.