The Tektronix 568 is a sampling oscilloscope, introduced in 1967, which takes 3S- and 3T-series plug-ins. Although it was intended to be used for sampling, it can also be used with non-sampling plug-ins of the 3A and 3B series.
Like the 561 and 564, the 568 does not contain vertical or horizontal amplifiers. The plug-ins directly drive the deflection plates. The 568 has multi-pin connectors on its rear panel that are routed to multi-pin connectors on the plug-ins. This is to support external control and measurement using, for example, a 230 and 241. The typical cable for connecting the 568 to the 230 is the 012-0119-01.
The 568 was distributed as a self-contained instrument and also as a component of integrated test and measurement systems such as the S-3100. As a part of the test and measurement systems, the 568 was sold at least until 1986.
A modification, 708P, was available for the 568 to give it a head multiplexer instead of a CRT.