GB579863A - Distance indicating radio detection system - Google Patents

Abstract

579,863. Radiolocation. STANDARD TELEPHONES & CABLES, Ltd. Feb. 18, 1944, No. 3111. Convention date, Feb. 20, 1943. [Class 40 (v)] [Also in Group XXXVI] In a pulse operated radiolocation system the range of a selected target is indicated at a remote point in terms of the pulse recurrence frequency which is controlled in accordance with the range of the target. A modulator 12 and transmitter 10 radiate pulses 11, which are received after reflection by receiver 14 which is blocked during emission of pulses by circuit 18. The received echo pulses are displayed as vertical deflection on the oscillograph 21, the time base for which is provided by generator 20, triggered by the modulator. In order to select a particular echo pulse such as 30 and to determine the time interval between it and the transmitted pulse, an adjustable delay device 32' of the type; for example described in Specification 571,772 is fed with the modulator pulse, and the delayed pulse 35 shaped in circuit 34, is fed to the vertical deflecting plates of the oscillograph and aligned with the peak of a selected signal. The adjustment of delay device 32 is then a measure of the range of the selected target and the control of device 32 is ganged with the timing control of the modulator to cause the pulse recurrence frequency to assume a value indicative of the target range. At points remote from the transmitter are receivers adapted to receive the transmitted pulses, comprising flip-flop circuits which generate pulses of constant area corresponding to each transmitted pulse, which are integrated by a meter the indication of which is then proportional to pulse recurrence frequency, and which may be calibrated in terms of range. The range indications and the rate of change of the recurrence frequency can be employed to predict the course of a target.