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Tektronix DC502
550 MHz frequency counter
Tektronix DC502

Produced from 1972 to 1977

(All manuals in PDF format unless noted otherwise)
Manuals – Specifications – Links – Pictures

The Tektronix DC502 is a 550 MHz frequency counter plug-in for the TM500 system.

It measures frequencies from 10 Hz to 550 MHz or totalizes events up to the readout capacity of 107−1 at the maximum rate of 550 MHz.

Key Specifications

Resolution 7 digits
Frequency range 10 Hz to 110 MHz (Direct input); 50 MHz to 550 MHz (÷10 input)
Sensitivity 300 mVp-p or 100 mVrms sine (Direct input); 500 mVp-p or 170 mVrms sine (÷10 input)
Input impedance 1 MΩ (Direct input); 50 Ω (÷10 input)
Gate time 0.01 s, 0.1 s, 1.0 s, or 10 s
Stability 1×10−5 (10 ppm) standard, 5×10−7 (0.5 ppm) with Opt.01
  • 7-digit LED Display, automatic decimal point and leading zero blanking
  • manual Start/Stop (Totalize)
  • adjustable trigger level on direct input

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.

LEDs indicate when the gate is armed, and whether displayed numbers are in kHz or MHz, and when register overflow occurs.

The internal clock is 1 MHz. The Opt.05 high stability oscillator runs at 5 MHz with an additional by-5 divider.


Rear Interface

Connector Pin Signal
28B Second decimal point output
27B MHz light output
27A Internal Scan Clock Disable
25B External Scan Clock input
25A Time Slot Zero
24B Internal Scan Clock output (2 kHz)
23B Overflow
22B MSD output
21B BCD output 2
20B BCD output 8
20A BCD output 4
19A BCD output 1
19B Data Good

Data is output serially by digit.