GB744354A - Telemetry calibration system - Google Patents

Abstract

744,354. Electric indicating systems. ARMSTRONG WHITWORTH AIRCRAFT. Ltd., Sir W. G. Feb. 23. 1953 [April 5, 1952], No. 8777/52. Class. 40(1) In a telemetering system a number of signals, of which the durations or intensities represent the values of the quantities to be telemetered; are sequentially transmitted as modulations of a carrier and are converted at the receiver into voltages or pulse positions representing the durations or intensities of the signals, these voltages or pulses being applied in sequence, together with a time base signal, to a cathoderay tube in order to produce a display; a second display providing a datum for comparison with the first is produced by the application to the cathode-ray tube of the 'output of a calibrated generator in conjunction with the time base signal, the telemetering signals and the output of the calibrated generator being fed through common circuitry and applied alternately to the cathode-ray tube so that the two displays are visible at the same time. As shown, a line 11 carries incoming telemetering signals and a synchronizing signal which is separated at 12 and triggers a generator 14 to prbduce a. sawtooth time base signal 22. This is applied to a cathoderay tube 44 and also to a differentiating circuit 20, 21 which produces narrow pulses 24 which are passed through an amplifier and buffer 25 and a dividing circuit 26 to provide two oppositely-phased signals 28, 29 of square waveform and half the original' frequency. These are arranged to gate amplifiers 16 and 36 respectively so that the' telemetering signals from line 11 and a fixed; frequency signal from a calibrated oscillator 40 are fed alternately through a common frequency discriminator and demodulator 42 to the cathode-ray tube 44, producing a histogram 46 and a datum line 47 respectively. In modifications (not' shown), the output of the calibrated oscillator 40 may be variable or a plurality of datum lines may be displayed. In a pulse system (not shown) the value of the quantity to be telemetered is represented by the duration of telemetering signal and is indicated on the cathode-ray tube 44 by the position of a pulse with respect to a time base.:In this system the calibrated oscillator 40 and the common frequency discriminator 42 are replaced by a time calibration generator and a detector respectively.