GB786766A - Improvements in or relating to pulse radar apparatus - Google Patents

Abstract

786,766. Frequency-changing. DECCA RECORD CO., Ltd. Feb. 9, 1956 [March 30, 1955], No. 9339/55. Class 38 (2). [Also in Group XL (c)] A pulse generator comprises a full-wave rectifier frequency doubler to which an alternating current input is applied and a pulse producer coupled to the output of the doubler via a second doubler so that the pulse repetition frequency is four times that of the A.C. input. The Figure shows the pulse generator of a modulator for a pulse radar apparatus in which an A.C. input, for example, at 1000 c/s. is applied to a frequency doubler comprising rectifiers 13, 14, the output of which has a resonant circuit 26, 27 tuned to twice the frequency of the original A.C. input. The voltage across the tuned circuit is applied via triode phase-splitter stage 25 to a further frequencydoubler comprising rectifiers 36, 37, the output of which is applied to trigger blocking oscillator stage comprising tube 43 to produce a pulse train at output 47 having a P.R.F. which is four times that of the original A.C.. input. In a modification, Fig. 2 (not shown), the output from the second frequency doubler is shaped by triggering a cathode-coupled flip-flop stage, the pulse output from which is applied via a differentiating circuit so that the resulting positive peaks trigger the blocking oscillator pulse generator stage. The P.R.F. of the generated pulse train may be increased by increasing the number of frequency-doubler stages in the input circuit.