The P77DESKEW probe deskew fixture provides an edge source to time-align
(deskew) signals at the inputs of P7700 Series probes. The fixture provides a
means to deskew two probes at the same time. The probe and the fixture are
powered by one of the USB ports of the oscilloscope; a USB cable (Tektronix part
number, 174-6919-xx) is included with the fixture.