281

{{Instrument Sidebar |manufacturer=Tektronix |model=281 |class=Reflectometer |series= |summary=TDR Pulser |image=Type 281 1.JPG |caption=Tektronix 281 TDR Pulser |introduced=1966 |discontinued=(?) |designers= |manuals=

• [[Media:070-0515-00.pdf|Tektronix 281 Manual] (PDF)

}} The Tektronix 281 TDR Pulser is an accessory that plugs into the probe power jack on 1S1, 3S1, and 4S1 plug-ins.

It has two GR-874 connectors. One connector is intended to be connected to the input of a sampling oscilloscope. The other connector attaches to the cable that is being tested.

The 281 periodically produces a pulse that is launched down a cable. The returning reflection is allowed to pass into the oscilloscope for measurement. The pulse is specified to be 460 mV, with a rise time of 750 ps or less, with a 5 μs pulse width.

The 281 uses a 1N3130 tunnel diode as a multivibrator. The multivibrator drives a common-base output transistor.

Pictures

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  Entry in 1968 catalog

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  schematic