Agilent Technologies 87075C manual Internal Transfer Standards

Test Set Cal and SelfCal

Test Set Cal and SelfCal: Theory of Operation

Figure 3-3 Internal Transfer Standards

	A SelfCal is an automatic measurement of the test set internal standards that allows
	the system to remove system drift that occurs due to environmental changes such as
	temperature. SelfCal allows the multiport system to recalibrate itself without having
	to disconnect the DUT or connect any additional external standards or cables to the
	system.
	A SelfCal can be initiated manually. It is also possible to automatically perform a
	SelfCal at regular, frequent time intervals. If the operating temperature of the
	analyzer and test set is within the specified range (refer to Chapter 8), the
	recommended time interval is about once an hour.
CAUTION	Performing a Test Set Cal will effectively calibrate out the initial effects of any
	external cabling and/or test fixtures. However, it must be noted that although the
	SelfCal can remove drift internal to the measurement system, it cannot remove any
	drift associated with cables, test fixtures and connections beyond the internal
	transfer standards.
	As shown in Figure 3-4, the Test Set Cal initially removes the effects of drift
	associated with hardware in the area designated by arrow “A.” SelfCal can only
	remove the effects of drift from the area designated by arrow “B.”

46 Chapter 3