GB614595A - Improvements in or relating to radar apparatus - Google Patents

Abstract

614,595. Television. PARTINGTON, G. E. July 16, 1946, No. 21316. [Class 40 (iii)] [Also in Group XL (c)] Picture signals corresponding to a chart or other pictorial representation of the area scanned by P.P.I. radar apparatus are reproduced, together with the normal target display, on the P.P.I. cathode-ray tube screen. The chart which may comprise a transparency 5 is arranged to be scanned by the luminous spot on the screen of a short persistence cathode-ray tube 1, the deflection circuits 3 being operated from the same scanning circuits as are employed for the P.P.I. tube (not shown) and the picture signals developed by the photo-electric cell 7 are applied to the input circuit of the P.P.I. apparatus after amplification and limiting in 8. The two sets of signals (i.e. picture signals and radar signals) may be strongly differentiated from each other by applying them with different amplitudes to the P.P.I. tube to produce a two-tone picture, or, if the screen in the P.P.I. tube is of the type in which the colour glow depends on the intensity of the electronic bombardment, a two-colour picture. Instead of the abovedescribed arrangement for producing the picture (i.e. chart) signals, the tube 1 may be replaced by a picture signal generating tube such as an iconoscope, in which case the chart need not be in the form of a transparency. Alternatively, mechanical scanning means may be employed to produce the picture signals. The arrangements may be utilized to generate artificial signals for testing a P.P.I. apparatus.