1. A sampling technique for a waveform measuring instrument, comprising: processing a series of digital signal samples through a uniform decimator to extract at least one uniform decimated sample value for each sample interval in a first series of sample intervals; processing the series of digital signal samples through a low frequency dither decimator to extract at least one low frequency dither decimated sample value for each sample interval in a second series of sample intervals; and processing the series of digital signal samples through a digital peak detector to extract a maximum sample value and a minimum sample value for each sample interval in the third series of sample intervals.