Protection of a quiz computer against manipulation of its timer by varying the temperature, by provision of an additional timer circuit with a different temperature coefficient and a program for checking the two circuit times

摘要

Quiz computer with input (2) and output (3) units linked to a processor (4) The processor has a timer (5) with a clock generator (6) and a time element (7) for controlling the time. The time element has a give temperature coefficient. The computer has means (8) for protection of the computer against manipulation of the timer by varying the temperature. Physically the timers are surrounded by injection molded masses to provide insulation against temperature changes. The protection means consist of an additional time element (10), clock generator (9) and timer (11). The additional time element has a different temperature coefficient. A program running in the processor compares the two time. The invention also relates to a corresponding method in which the difference in the times indicated by the main timer and the additional timer is calculated and compared to a threshold value. If the value is exceeded the time is taken from the additional timer.