191

Manuals – Specifications – Links – Pictures

The Tektronix Type 191 Constant Amplitude Signal Generator is a sine wave source introduced in 1966. The predecessor of the 191 was the 067-506.

It produces sine waves whose amplitude remains constant as the frequency is varied, provided the load limitations of the instrument are not exceeded. It covers frequencies from 350 kHz to 100 MHz in seven bands. 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 and 0.5-5 V (Peak-to-Peak)
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	Into 50 Ω at 50 KHz it's ±3% for 5 mV to 5.5 V, except for 5 mV and 55 mV and a frequency >42MHz where it's +3% and -5%.
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