Tektronix DC502

The Tektronix DC 502 Digital Counter will measure frequencies from 10 Hz to 55 MHz or totalizes the event up to the readout capacity of 10x7-1 at the max rate of 550 MHz. the frequency measurements are accomplished using one of two inputs. The DIRECT INPUT has a frequency range of 10 Hz to 110 MHz, a 1 megohm input impedance, 300 mV p-p sensitivity (100 mV rms sine wave) and an adjustable trigger level range. The /10 PRESCALE INPUT has a frequency range from 50 MHz to 550 MHz with a 500 mV p-p sensitivity (170 mV rms sine wave) and a 50 Ohm input impedance. The manual totalizing mode with front panel start stop control is available in both inputs; from the prescale input, 1 displayed count per 10 input events will result. The measurement display is accomplished with 7 segment LEDs in a seven digit readout. The decimal point is automatically positioned by the measurement interval seleted, and leading zeros ( those to the left of the most sig digit or those to the left of the decimal point) are blanked. LEDs indicate when the gate is armed, and whether the displayed numbers are in kHz or MHz, and when the register overflow occurs. Four gate times of 0.01 s, 1.0 s, and 10 S are provided. A standard internal 1 MHz clock is also provided with 1x10-5 accuracy.