Agilent Technologies HP 8719D Service Manual page 449

Connector repeatability is the random variation encountered when connecting
a pair of RF connectors. Variations in both reflection and transmission can be
observed.
The listing below shows the abbreviations used for random errors in the error
models and uncertainty equations.
Rnt = raw noise on trace (rms)
n
Rnf = raw noise on floor (rms)
n
Crrl = port 1 connector reflection repeatability error
n
Crtl = port 1 connector transmission repeatability error
n
n
n
Sources of Drift Errors
Drift has two categories: frequency drift of the signal source and
instrumentation drift. Instrumentation drift affects the magnitude and phase of
both reflection and transmission measurements.
The primary causes for instrumentation drift are the thermal expansion
characteristics of the interconnecting cables within the test set and the
conversion stability of the microwave frequency converter.
The list below shows the drift errors in the error models and uncertainty
equations.
Dmxbx, Dmsax = drift magnitude
n
Dpfxbx, Dpfsax = drift phase/f
n
Sources of Additional Measurement Errors
Two additional categories of measurement errors are connection techniques and
contact surfaces.
The connection techniques category includes torque limits, flush setting of
sliding load center conductors, and handling procedures for beadless airlines.
The contact surfaces category includes cleaning procedures, scratches, worn
plating, and rough seating.
These types of errors are not accounted for in the uncertainty analysis.
Determining System Measurement Uncertainties A-3