The 1991 is a Universal Timer/ Counter designed for system or bench use. Basic measurement functions include Frequency, Period, Time Interval, Totalize, Phase, and Ratio.
- Frequency Range:
- Input A: DC to 160 MHz DC-coupled; 10 Hz to 160 MHz AC-coupled;
- InputB: DC to 100 MHz DC-coupled;10 Hz to 100 MHz AC-coupled.
- Sine Wave: 25 mVrms DC to 100 MHz; 50 mVrms to 160 MHz;
- Pulse: 75 mV p-p, 5 ns min.width