Meter for measuring an electrical parameter

A meter for performing a measurement of an electrical parameter, comprising:

• a sensor configured to measure the electrical parameter;
• a processor configured to cause the meter to:
• sample an output from a sensor of the electrical parameter to produce at least one sample;
• and
• iteratively perform steps of:
• sampling the output from the sensor to produce one or more further samples;
• processing the at least one sample and each of the one or more further samples to generate a plurality of processed samples;
• holding in memory a stored array of processed samples for each iteration;
• determining a measure of statistical variability from the stored array of processed samples for the respective iteration;
• determining a measure of statistical variability of a mean of the processed samples for the respective iteration from the measure of statistical variability and from the number of samples used to generate the measure of statistical variability;
• comparing the measure of statistical variability of the mean of the processed samples with a pre-determined threshold;
• and
• generating an electrical signal indicating a state of the measurement if the measure of statistical variability of the mean of the processed samples is less than or equal to the pre-determined threshold,
• wherein said processing comprises processing the at least one sample and each of the one or more further samples to derive a curve describing a trend and each processed sample represents a difference between the respective sample and the curve.