GB844872A - Improvements in "function generator" - Google Patents

Abstract

844,872. Frequency detectors. GENERAL ELECTRIC CO. June 27,1957 [June 29,1956],No. 20301/57. Class 40(5). [Also in Group XXXVI] The mean pulse rate of pulses generated by a random pulse source 53 may be measured by applying them to a bi-stable valve circuit 57 whose output is alternately positive and negative pulses applied to several parallel branches of series R-C, R-L or L-C circuits forming a network 60 with output applied to a full-wave rectifier circuit 63, 64, C. The values of R, C or L in each branch may be determined by inverse Laplace transforms so that the mean current output is proportional to log (1 + rT) where r is the pulse rate and T a constant, or to rα where is a constant less than unity. In theory an infinite number of parallel branches corresponding to terms of an infinite series should be used but a finite number of branches produces an approximation. The double diode 56 permits pulses to be semidirectionally injected into the system. The pulse source 53 may be a radiation detector of the proportional counter or scintillation type with output applied through a back biased triode controlling the output pulse rate. Moreover the ratemeter can be inversely operated by applying a control wave to the output capacitor C so that the D.C. amplifier 55 responds to the difference between the ratemeter output and control wave and controls the mean rate of pulse generation at terminal 52 in accordance with the control wave at terminal 51 and the design of network 60, i.e. the pulse rate may be an exponential or other function of the control current at terminal 51. Finally, the variable rate pulses at 52 may be applied to a further ratemeter circuit similar to 54 but with a different synthesized network 60 so that a function is generated from its rectified output related to the function applied at terminal 51.