GB604673A - Improvements in or relating to radar systems - Google Patents

Abstract

604,673. Radiolocation; valve circuits. ELLIOTT, W. S., GAUNT, H., and WEBLEY, R. S. March 7, 1945, No. 5727. [Classes 40 (vi) and 40 (vii)] In a pulse radar system, moving objects are detected by storing signals received during whole or part of one scan of the aerial as a charge pattern on the target of an electronic storage tube and by deriving from the stored signals and corresponding signals received during a subsequent scan, a differential output representative of objects of changing position only. The storage tube 1 is similar to that described in Specification 604,672 and signals from the receiver 13 fed via unit 19 to the modulator electrode 3 are recorded on the target electrode 9 during one scan of the aerial 15 as a master, suitable deflecting voltages being fed to plates 7, 8 from generators 21, 22 which are synchronized at pulse recurrence frequency and aerial scan frequency respectively, by the transmitter 14 and aerial rotating means 17 under the control of square pulses of aerial scan frequency from unit 23. During alternate scans, the output from unit 23 controls the power supply unit 20 to condition the tube for reproduction and cuts off the modulating unit while opening the switching unit 27 to permit the signals direct from the receiver and those reproduced signals from the tube, amplified at 26, to pass to the cancellation unit 28. The differential output from unit 28, corresponding to the non-repetitive portions of the signals on successive scans produced by movement of the reflecting objects, is fed to a P.P.I. or similar display unit 29, the time-base 30 for which is synchronized by locking pulses from the transmitter. In order to provide the same number of scans on the final display as is performed by the aerial system, two identical storage tubes may be employed, each storing signals during alternate scans so that differential signals are obtained for display during every scan. Specification 604,671 is referred to in the Provisional Specification.