PG508
The Tektronix PG508 is a 50 MHz pulse generator plug-in for the TM500 system.
Pulses can be triggered by an external input, a manual trigger button, or an internal period generator (optionally gated by the trigger input).
The trigger signal can be undelayed, delayed by a selectable time, or both (in which case double pulses are generated).
The pulse duration, leading and trailing edge transition times, high- and low-level amplitude can be controlled independently.
Period, delay, duration, and transition time switches each feature a custom position where a user-supplied internal capacitor determines the timing.
Key Specifications
| Period | external, or internal <20 ns to >200 ms in 7 decade steps plus variable; ≥200 ms possible in custom range |
|---|---|
| Jitter | <0.1% +50 ps |
| Delay Time | <10 ns to >100 ms in 7 decade steps plus custom position and variable control; ≥100 ms possible in custom range |
| Pulse Duration | square, or <10 ns to >100 ms in 7 decade steps plus custom position and variable control; ≥100 ms possible in custom range |
| Transition time | Ranges 5 ns to 500 μs in decade steps plus custom position; separate ×1 to ×100 variable controls for leading and trailing edge (5 ns to 50 ms effective) |
| Output level | High and low levels adjustable independently in −20 V to +20 V range, limited to max. 20 Vp-p / min. 1 Vp-p (open circuit), 50 Ω source impedance (−10 V to +10 V, 0.5 to 10 Vp-p into 50 Ω) |
| Trigger/Gate input | Sensitivity 80 mVp-p to ≥10 MHz, 250 mVp-p to ≥50 MHz at 50 Ω impedance, max. ±5 Vpeak; 1 MΩ // 20 pF optionally selectable (internal switch), max. ±20 Vpeak |
Rear Interface
(right-hand plug-in slot as viewed from front)
- 27B/28B(GND) Trig output (complement polarity installed; for normal polarity, front panel input requires optional cable and front output disconnection) [note error on manual p.1-12; table 1-13 is correct]
- 24B/25B(GND) Trig input (with optional cable, front panel input must be disconnected)
- 25A/26A(GND) Amplitude Monitor (from output via 27 kΩ)
- 22A External Low Level Control Input (requires internal jumper and trim)
- 22B External High Level Control Input (requires internal jumper and trim)
Custom connection solder pads ae available on the left plug-in slot, which is otherwise used only for hte associated pass transistors in the mainframe.
References
- Designs by the Masters – ±20 V, 5 ns, 50 Ω Amplifier (detailed discussion of the PG508 output stage). Horowitz & Hill, Art of Electronics - The x-Chapters, p.150+
