ABSTRACT
The main requirement is for an analogue-to-digital converter (ADC) to convert the signal and suitable software. The ADC should preferably be at least 12-bit rather than the 8-bit ADC sometimes supplied in microcomputers; see A. C. Armstrong and W. B. Whalley for further discussion. Analogue signals can be used directly to give deflections on a suitable voltmeter or ammeter. For recording such a signal, it must be fed into a suitable device. Two main types of these can be considered: chart recorders and oscilloscopes. Oscilloscopes are devices similar to a television, but where the electron beam is made to traverse the screen in accordance with a selected, horizontal, time base and its y deflection is a function of the applied signal voltage. Analogue signals are those which are replicas of another signal but in a different form; variations of the measurand are followed by the analogue electrical signals as, for example, a change in voltage.
