GB728112A - Improvements in or relating to pulse-radar equipment - Google Patents

Abstract

728,112. Pulse radar. PHILIPS ELECTRICAL INDUSTRIES, Ltd. Aug. 19, 1953 (Aug. 22, 1952], No. 22874/53. Class 40 (7). Relates to a pulse radar with a normal range display, e.g. a P.P.F. 19, Fig. 2a, having an adjustable range marker 20 and a further similar type display, 22, Fig. 2b, displaying in expanded form a range internal 23<SP>1</SP>-23, Fig, 2a, centred about the range mark 20; as shown in Fig. 2b the expanded display has an open centre, the inner boundary 24, marker 25 and outer boundary corresponding to the ranges 23<SP>1</SP>, 20 and 23 respectively in Fig. 2a. According to the present invention the adjustable range marker is produced by applying an exponential waveform a, Fig. 3, synchronous with the pulse transmission together with an adjustable D.C. range voltage E to a comparator to generate a marker pulse when the input voltages are equal in amplitude and the displayed range interval is initiated by a trigger pulse generated by applying a second exponential waveform b together with the D.C. range voltage to a second comparator, the two waveforms a and b having the same time constant but different initial amplitudes so that the time interval between the 'marker and trigger pulses remains constant when the range voltage is varied, e.g. from El to E2. As shown in Fig. 1 the marker pulse is generated in circuit 17 by applying a sync. pulse from the timing circuit 12 to an electronic switch 34 shunted across a capacitor 29 which is in series with a charging resistor 30, the resultant waveform a at the junction of R30 and C29 being applied to the first comparator 31 together with the range voltage from potentiometer 3b, the output marker pulse from the comparator being applied to intensity modulate the main and expanded displays 19 and 22 to produce markers 20 and 25 respectively. The trigger pulse is generated by a corresponding cct 26 (29<SP>1</SP>, 30<SP>1</SP>, 31<SP>1</SP>, 34<SP>1</SP>) but the waveform b appears at a tapping 32<SP>1</SP> on R30<SP>1</SP> and the output pulse from comparator 31<SP>1</SP> triggers the highspeed time base generator 28 for the expanded display 22. Alternatively the switch 34<SP>1</SP> may be connected to the tapping 32<SP>1</SP> as shown by the dotted connection 35<SP>1</SP> or each sawtooth generator may comprise a parallel R.C. network connected in series with an electronic switch.