Patent GB-1177821-A (GB)
Title: Method of Pre-Setting and/or Simulating Electrical Quantities
IPC: G01R31/00
Filed: 1967-02-24
Abstract: 1,177, 821. Programmed control of testing. LICENTIA PATENT-VERWALTUNGS-G.m.b.H. and ENTWICKLUNGSRING SUD G.m.b.H. Feb.24, 1967 [Feb.24, 1966], No.8980/67. Heading G3N. Electrical quantities characterizing an operational system are present and/or simulated for the purpose of testing electrical elements, components and circuit arrangements by storing the quantities in a first store, allocating identification to the quantities, and selecting quantities of interest for transfer to a second store and subsequent transfer to a third store through a function generator merging the individual values, the contents of the third store being used for the control of power amplifiers yielding desired pre-set or simulated electrical quantities. As shown, electrical quantities measured during the operation of a power supply on board an aircraft are stored on independent channels of a magnetic tape device 10 and time coded by a device 11. The coding device 11 consists of a time-code generator having an output representing the elapsed time which serves for continuous identification of the stored values, a time-code searching device selecting a predetermined identification produced by the time-code generator, and a control device 12 which after a selection initiates the continuous extraction of the stored value for a predetermined period. The selection is effected by the use of a cathode-ray oscilloscope 13 and the voltages for test are fed through an analoguedigital converter 14 into an intermediate store 15, which is interrogated and the derived signals fed through a digital-analogue converter to a magnetic tape device 16. A device 18 extends the time of display of the derived signals on the oscilloscope 13 and a device 19 provides auxiliary marking pulses, in accordance with a fixed programme or on instructions from an operator, which are recorded on a separate channel of the tape device 16. The stored values of the tape device 16, through an electronic change-over switch 20, are supplied to a third magnetic tape device 21. A function generator 22, comprising a controlled oscillator, takes over at the end of a stored signal by means of the switch 20 and, detecting the following stored signal, smoothly adapts the trans-function supplied by the oscillator to the following stored signal value. When this has been done, the switch 20 connects the tape devices 16 and 21 together. A programmed function generator 23 is associated with the generator 22 whereby any desired function, instead of the stored values, can be connected selectively to the tape device 21 through the switch 20. The contents of the tape device 21 control a power amplifier 24, of low internal resistance, the output of which is connected, through filters 25, to the object under test, the quantities simulated appearing on a bus-bar 26. Switching voltage peaks are superimposed on the output from the power amplifier from a pulse-generator 27, controlled by auxiliary pulses recorded on a separate channel and produced by the identification generator 19. It is stated that the stored signals from device 16 may be supplied in a required random sequence to a fourth tape device not shown, under control of a selection device, not shown, and that the tape device 10 may be used for the tape-device 21 or the fourth tape device. Arrangements for the simulation of polyphase networks are described, Figs.2 and 3 (not shown), and the use of two prepared tapes and two magnetic tape-devices, Fig. 4 (not shown) for the carrying- out of a simulation which is unlimited by time.