067-0508-00: Difference between revisions
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The Tektronix 067-0508-00 Amplitude Calibrator generates a square-wave with | The '''Tektronix 067-0508-00''' Amplitude Calibrator generates a square-wave with | ||
two precisely controlled voltages and | two precisely controlled voltages and 50 Ω impedance at both voltages. | ||
This could be achieved by a | |||
an amplifier with | This could be achieved by a 50 Ω resistor in series with the output of | ||
of negative feedback). But that is not how Tektronix did it. They used a | an amplifier with 0 Ω output resistance (e.g., an opamp with plenty | ||
shunt resistance at the output, and a precision DC current source | of negative feedback). But that is not how Tektronix did it. They used | ||
a 50 Ω shunt resistance at the output, and a precision DC current source | |||
that can be steered toward the output or toward a dummy current sink | that can be steered toward the output or toward a dummy current sink | ||
transistor. The built-in multivibrator controls the steering of the | transistor. The built-in multivibrator controls the steering of the | ||
Line 12: | Line 13: | ||
<gallery> | <gallery> | ||
Tek 067-0508-00 1.jpg | |||
Tek 067-0508-00 2.jpg | |||
Tek 067 0508 00-schem.jpg | |||
</gallery> | </gallery> | ||
[[Category:Calibration fixtures]] | [[Category:Calibration fixtures]] | ||
[[Category:Pulse generators]] | [[Category:Pulse generators]] |
Revision as of 11:21, 5 February 2016
The Tektronix 067-0508-00 Amplitude Calibrator generates a square-wave with two precisely controlled voltages and 50 Ω impedance at both voltages.
This could be achieved by a 50 Ω resistor in series with the output of an amplifier with 0 Ω output resistance (e.g., an opamp with plenty of negative feedback). But that is not how Tektronix did it. They used a 50 Ω shunt resistance at the output, and a precision DC current source that can be steered toward the output or toward a dummy current sink transistor. The built-in multivibrator controls the steering of the current.