067-0508-00: Difference between revisions
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The Tektronix 067-0508-00 Amplitude Calibrator generates a square-wave with | |||
two precisely controlled voltages and 50-ohm impedance at both voltages. | |||
This could be achieved by a 50-ohm resistor in series with the output of | |||
an amplifier with 0-ohm output resistance (e.g., an opamp with plenty | |||
of negative feedback). But that is not how Tektronix did it. They used a 50 ohm | |||
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. | |||
* [http://w140.com/tek_067_0508_00.pdf Tektronix 067-0508-00 Manual (PDF)] | * [http://w140.com/tek_067_0508_00.pdf Tektronix 067-0508-00 Manual (PDF)] | ||
Revision as of 14:09, 14 April 2012
The Tektronix 067-0508-00 Amplitude Calibrator generates a square-wave with two precisely controlled voltages and 50-ohm impedance at both voltages. This could be achieved by a 50-ohm resistor in series with the output of an amplifier with 0-ohm output resistance (e.g., an opamp with plenty of negative feedback). But that is not how Tektronix did it. They used a 50 ohm 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.
