Tektronix TG501

This time mark generator provides marker outputs from five seconds to one nanosecond.

A unique feature on this unit is a variable timing output with a front panel two digit LED display which indicates percentage of timing error between the normal time interval and a variable interval set to line up the marker pulse with graticule or division mark on the display.

This feature not only provides direct readout in terms of percent error, but also helps eliminate errors associated with visually estimating error from a display.

Since many specifications are given in percentages, the error readout eliminates the need for computations and, additionally, lessens parallax discrepancies.