The Keithley 775A is a nine digit, microcomputer based, fully
programmable, universal counter / timer. The Counter / Timer 775A measures Frequency A, Frequency B, Frequency
C, Period, Period Averaged, Time Intervals A - B, Pulse Width (positive or negative) A with high resolution.
The display consists of 9 digits with an additional digit for exponent. The built-in interface makes the instrument
fully programmable over the IEEE-488 bus. The Keithley 775A contains a programmable trigger level that allows
additional flexibility in measurements over the bus (e.g. measuring rise and fall time with trigger points other
than 10% and 90%). Gate time is programmed in 46 steps from 100psec to 10sec or external from the front panel
or over the bus.