Tektronix TG501A

The TG501A Time Mark Generator provides marker outputs from 1 ns to 5 sec. A unique feature of the TG501A is a variable timing output with a front panel 2-digit LED display. The display indicates percentage of timing error between the normal time interval and a variable interval that lines up the marker pulse with graticule or division marks 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.