The Tektronix DC508 is a 1 GHz counter plug-in for the TM500 system.
The DC508A version (1980) extended the frequency range to 1.3 GHz.
Both the DC508 and the DC508A use off-the-shelf divide-by-4 counter ICs as the prescaler. The DC508 uses a Motorola MC1697 (Tek part number 156-0923-00), which is rated to 1 GHz. The DC508A uses a Plessey SP8611B (Tek part number 156-1302-01), which is rated to 1.5 GHz.
- 1 GHz, 9 digits
- 0-100 MHz direct (15 mVRMS, 1 MΩ // 25 pF), gate times 1 ms to 10 s in decade steps
- 100 MHz+ via prescaler (20 mVRMS, 50 Ω input, fused), gate times 8 ms to 8 s in decade steps
- Functions: Frequency, events
- Option 1 − High accuracy time base
- Option 7 − Accepts rear panel control signals from a TR502 or SW503 to measure a marker frequency. Resolution and gating remote control circuitry is added to the DC508(A). Requires a TM503 - option 7 or an appropriately modified mainframe. This option inherently also adds option 1.
DC508A in TM515 with other TM500 gear