The Agilent-Hp 5315A Universal Counter measures signals over 0.1Hz to 100MHz range. The unit measures Period: 10 ns to 105 Sec; Time Interval: 100 ns to 105 Sec; Time Interval Average: 0 ns to 105 Sec; Time Interval Delay: holdoff, variable delay of nominally 500s to 20 ms between START (channel A) and STOP (channel B); and Ratio: 0.1Hz to 100MHz, both channels. A totalize function with manual or external gating is also provided. All measurements, except totalize, have up to 8-digits resolution. Two channels provide time interval measurements.