Patent GB-652672-A (GB)
Title: Improvements in or relating to recording systems
IPC: G01S7/04
Filed: 1946-10-04
Abstract: 652,672. Radiolocation ; valve circuits. RAYTHEON MANUFACTURING CO. Oct. 4, 1946, No. 29620. Convention date, Oct. 19, 1945. [Classes 40 (vi) and 40 (vii)] In a pulse radar system wherein the display arrangement comprises a mechanically-driven indicator providing a permanent record, the received signals are applied to a gating circuit to which are also applied gating pulses, the timing of which is slowly varied while the position of the indicator is moved correspondingly so that. a display corresponding to the echo signals received is produced. A negativegoing pulse from the transmitter 1 is applied to a grid of the double-triode valve 26 which comprises a flip-flop circuit. There is consequently produced at the point K after an interval dependent upon the value of the condenser C, a positive pulse, due to the action of the differentiating network C1, Rg upon the signal appearing at the anode 27. The positive-pulse is applied to the grid electrodes of a doubletriode 35 connected as shown in series with the output of the radar receiver 10. The double-triode 35 comprises a gate circuit which passes the receiver output only on the application of a positive-pulse thereto. The gate-circuit output is rectified and applied to the indicator comprising a stylus 7 and recording paper 8. The condenser C is made to vary its value continuously by means of the motor 36 and the stylus is moved rotationally in accordance therewith so that each angular position of the stylus arm corresponds to a predetermined echo time. The paper is moved continuously in a perpendicular direction to the motion of the stylus so that successive records of an echo-signal appear side by side. The system may alternatively be made to produce a P.P.I. type of record, Fig. 3 (not shown). Alarm circuits. An arrangement is provided whereby a warning indication is obtained when an echo signal is received within a predetermined interval after the transmission of an exploring pulse. The received. signals are applied to the grid of a valve 40 which is normally non-conducting, due to a positive bias applied to its cathode. Pulses applied to the cathode circuit at the instants of pulse transmission charge the condenser therein and reduce the positive bias on the cathode, so that, for a predetermined interval after each pulse transmission, the received pulses have sufficient amplitude to overcome the bias and cause the valve to conduct, thereby operating an audible alarm. The Specification as open to inspection under Sect. 91 describes a system, Fig. 4 (Cancelled), wherein the transmitted pulses are applied from circuit 60 to generating circuits R-1, R-2, &c., which produce gating pulses covering between them the whole time-interval over which measurement is desired. The output of receiver 61 is applied to a plurality of gating circuits G1, G2, &c., to each of which a respective gating pulse is applied. The output of each gating circuit is taken to a respective stylus S-1, S-2, &c., the styli being arranged so that the echo signals are displayed according to range. An alarm circuit 63 may be selectively connected to any one of the gate-circuit outputs to indicate the presence of an echoproducing object within any selected element of range. This subject-matter does not appear in the Specification as accepted.