Record length refers to the amount of memory dedicated to storing digitized samples for postprocessing or display for a single acquisition. In a digitizer, record length limits the maximum duration of a single-shot acquisition. For example, with a 1,000-sample record and a sample rate of 20 MHz, the duration of the acquisition is 50 µs (the number of points multiplied by the acquisition time per sample, or 1,000 x 50 ns). With a 100,000-sample record and a sample rate of 20 MHz, the duration of acquisition is 5 ms (100,000 x 50 ns).
In many cases, measurement quality depends on the digitizer's ability to take a sustained acquisition while maintaining high sampling rates. In these cases, the amount of acquisition memory determines the fidelity of the acquired signal. High-speed digitizers with deep onboard acquisition memory have the ability to take enhanced time and frequency-domain measurements.