191
The Tektronix Type 191 Constant Amplitude Signal Generator is a sine wave source introduced in 1966 to replace the earlier 067-506.
It produces a sine output from 350 kHz to 100 MHz in seven bands whose amplitude remains constant as the frequency is varied, provided the load limitations of the instrument are not exceeded. The output amplitude can be adjusted in calibrated steps from 5 mV to 5 V in three ranges.
Key Specifications
| Output impedance | 50 Ω |
|---|---|
| Amplitude range | 5–50 mV, 50-500 mV, 0.5-5 Vp-p |
| Amplitude accuracy | At 50 kHz into a 50 Ω load: ±3% for 0.5–5 V range; ±4% for 50–500 mV range; ±5% for 5–50 mV range |
| Amplitude regulation | ±3% for 5 mV to 5.5 V into 50 Ω at 50 KHz; +3%/-5% for 5 mV and 55 mV ranges or frequency >42 MHz |
| Frequency range | 350 kHz – 100 MHz |
| Frequency accuracy | Within ±2% of the selected frequency when the output is terminated with 50 Ω |
| Harmonic content | Typically less than 5% |
Links
Documents Referencing 191
| Document | Class | Title | Authors | Year | Links |
|---|---|---|---|---|---|
| Tekscope 1970 V2 N3 Jun 1970.pdf | Article | Tektronix Signal Sources | 1970 | 2101 • 2901 • 114 • 115 • R116 • 106 • 191 • 284 • 140 |
Internals
The oscillator is a Colpitts oscillator using a 7119 tube.
A peak-to-peak detector made with two GaAs diodes measures the swing of the oscillator and produces a DC feedback signal that controls a series voltage regulator that supplies power to the oscillator.
The calibration procedure in the manual makes use of a 661 to accurately view the output waveform.
Pictures
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Front view
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Top internal view
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Bottom internal view
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Left internal view
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Right internal view
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Rear view
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Schematic
Components
Some Parts Used in the 191
| Part | Part Number(s) | Class | Description | Used in |
|---|---|---|---|---|
| 7119 | 154-0340-00 | Vacuum Tube (Dual Triode) | dual triode | 067-506 • 067-0532-00 • 191 • 3A3 • 3B4 • 3B5 • 516 • 545B • 549 • 661 • Chemtrix 205 |