661: Difference between revisions

The Tektronix 661 is a sampling scope that was made by Tektronix in the 1960's.  It accepts two plug-ins: a sampling unit and a timing unit.  At least three sampling units were made, the 4S1 (0.35 ns rise time) and the 4S2 (0.1 ns rise time), and the 4S3.  At least three timing units were made, the 5T1, 5T1A, and the 5T3.  The timing units use tunnel diode triggering.  Two coaxial cables in the scope connect the sampling unit to the timing unit.  One cable sends the trigger pickoff signal from the sampling unit to the timing unit.  The other cable sends the timing signal from the timing unit to the sampling unit, telling it when to sample.