TG501
The Tektronix TG501 is a time-mark generator plug-in for the TM500 system.
There is also a TG501A.
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 |
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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) |
Rear Interface Signals
Connector Pin | Description | |
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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 |
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 152-0503-00 step-recovery diode.
Links
- See the TG501/Repairs page for repair information.
- Tek TG501A Time Mark Gen Restoration by NFM @ YouTube
- TG501 Repair and Calibration by Zenwizard Studios @ YouTube
- TG501 In-Depth Troubleshooting of a Stubborn Unit by Zenwizard Studios @ YouTube
- TG501 In-Depth Troubleshooting of a Stubborn Unit Part 2 by Zenwizard Studios @ YouTube
Pictures
TG501
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TG501 early version
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TG501 late version
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TG501 early version
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TG501 early version
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TG501 output waveform