TG501A
The Tektronix TG501A is a time-mark generator plug-in for the TM500 system.
It was replaced by the TG501A in 1990.
Note the output must be terminated into 50 Ω or there may be no signal at all.
Key Specifications
| Interval | 1 ns to 5 s in 1−2−5 sequence |
|---|---|
| Timing accuracy | Stability 1×10-5, long-term drift 1×10-5 per month (with Option 1, 5×10-7 / 1×10-7 per month) |
| Error Readout | Accuracy 1 digit (±0.1% points), Range to ±7.5% |
| Amplitude | ≥1 V peak on 5 s through 10 ns; ≥750 mVp-p on 5 ns and 2 ns; ≥200 mVp-p on 1 ns (separate output) (all into 50 Ω) |
| Trigger Output | Slaved to marker output from 5 s through 100 ns. Remains at 100 ns for all faster markers |
| External Reference Input | 1 MHz, 5 MHz or 10 MHz; TTL compatible (internally hard wired so output frequencies counted down to 1 MHz) |
- Option 01 adds a 5 MHz tempature-compensated crystal oscillator (Y50), and a TTL decade counter (U50) for a stable, precise internal clock.
to be verified
Links
- Tek TG501A Time Mark Gen Restoration by NFM @ YouTube
- Tektronix TG501A Refresh and Check For a Viewer by Zenwizard Studios @ YouTube
Documents Referencing TG501A
- (no results)
Rear Interface
| Connector Pin | Description | |
|---|---|---|
| Signal | Return | |
| 28A | 27A | Marker Out (requires front BNC disconnection) |
| 27B | 28B | Trigger Out (requires front BNC disconnection) |
| 25A | 26A | Internal 1 MHz Clock Out (TTL) |
| 24B | 25B | External Clock Input |
| 26B | 22B | Data Good (High when BCD data valid) |
| 17A..20A | 22B | bit 4..1 BCD Display data, MSD |
| 21A..24A | 22B | bit 4..1 BCD Display data, LSD |
| 16A | 22B | Fast=Low, Slow=High |
to be verified
Internals
The TG501 internally produces a 1 MHz reference clock, either from an internal crystal oscillator, or from an externally supplied frequency.
A 100 MHz VCO is phase-locked to this reference frequency (in fixed-frequency mode) or to the output of a variable 1 MHz astable multivibrator (in variable frequency mode). When the variable oscillator is in use, its frequency is digitally compared to the fixed 1 MHz reference and displayed as a deviation in percent with a pair of LEDs indicating the sign (fast or slow).
A chain of dividers running off the 100 MHz clock provide the selectable output markers.
The 1 ns output uses a step recovery diode (HP 5082-8872, part 152-0503-00). to be verified
Prices
tba
Pictures
Better pictures needed - please contribute
Parts
Some Parts Used in the TG501A
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 152-0503-00 | 152-0503-00 | Discrete component | 500 ps step recovery diode | 1503C • TG501 • TG501A |