Method and apparatus for measuring parameters of an electronic system

An apparatus for measuring parameters of an electronic system by reference to an input series of data samples, the apparatus being arranged to process data samples being processed in a first stage so as to produce in real-time at least a first time-varying series of measurements for a given parameter characterising the data samples over observation intervals of a first magnitude, each of said observation intervals being many times longer than the sample period of the input series, the first stage comprising:

• means for deriving at least a first intermediate result from data samples of the input series received in a pre-determined sub-interval, and repeating the determination for successive sub-intervals so as to generate a series of first intermediate results;
• means for storing a finite number of said first intermediate results in a first data set, such that an observation interval of the first magnitude is encompassed by the set of sub-intervals corresponding to the stored intermediate results, the set of intermediate results being updated at least once per sub-interval by discarding an oldest intermediate result and adding a new intermediate result;
• means for deriving from the first data set a measurement of the given parameter corresponding to the observation interval and updating said measurement to generate said series of measurements as the first data set is updated.