GB1219092A - Improvements in or relating to function generator arrangements - Google Patents

Abstract

1,219,092. Electric selective signalling. ULTRA ELECTRONICS Ltd. 25 July, 1968 [26 July, 1967; 9 Nov., 1967; 28 Dec., 1967], Nos. 34242/67, 50971/67 and 58786/67. Heading G4H. The output 37 (Fig. 6) of a divider 18-24 receiving an input frequency signal is determined by the magnitude of an input control signal 34. The input frequency signal may be constant (Fig. 4, not shown) or varied by a voltage generator 39 (Fig. 6) between F and 2F in accordance with the value of signal 34. The divide-by-2 stages 18-24 of the divider are controlled by a switch 32 which selects one of the gates 25-31 in accordance with the range of the input to inhibit the associated divider stage and all following stages so that the output frequency is logarithmically related to the input 34. The apparatus may be used for converting a voltage representative of temperature into a frequency signal which is counted for a fixed time interval. In Fig. 7, signals V s , V T representing speed and temperature of an engine are compared with a staircase waveform from digital/analogue converter 47 controlled by a shift register 52 which is pulsed by a generator 50 until the error signal from network 45 passes through zero. The residual error which is within one step of the staircase is fed to a voltage controlled pulse generator 49 the frequency signal from which is fed via divider 65-70 controlled by the stages 53-58 of shift register 52 to a gated counter (not shown). The counter may be preset to indicate the life span of the engine and counted down so that the remaining life span is indicated. Other counters may count the total running time of the engine and the number of engine starts. Means may also be included to detect overspeed and overheating.