Anritsu ME7840A manual 5-32, HOT S22, Operations, Measurement, ME 7840A OMM, Procedure

HOT S22 OPERATIONS, MEASUREMENT

5-11HOT S22	The output match of a power amplifier under excited conditions is critical
	information that has a strong bearing on efficiency, output power, stabil-
	ity, and often the economic viability of the design. One way of dealing
	with this information—primarily in power devices operating well away
	from compression or in somewhat matched amplifiers— is a quasi-linear
	measurement of S22 while the amplifier is operating under normal drive.
	Such a measurement is termed hot S22, and it can provide (1) some infor-
	mation on the degree of mismatch in the system, (2) potential operational
	stability, and (3) the effects of the amplifier’s performance on subsequent
	stages or an antenna. In the PATS, the Hot S22 measurement uses one
	source (Source 2) to provide stimulus to the amplifier-under-test (AUT)
	input port while the other source (Source 1) provides a pilot tone injected
	to the output of the AUT for measuring S22 at the AUT output port.
	Procedure
		Prepare the ME7840A as shown in Chapter 3.
		Enter the appropriate test values in the displayed
		User Input screen. The input fields are described
		below:
		￿ S Parameter: Already set to “Hot S22” for test –
		input disabled.
		￿ Data Points: Drop down options ￿ number of data
		points in frequency sweep.
		￿ Frequency 1 (MHz): Lower frequency to be dis-
		played. Typically set to a value less than or equal
		to the main tone. Can be reset using slider control.
		￿ Frequency 2 (MHz): Upper Frequency to be dis-
		played. Set to a value less than the system’s maxi-
		mum frequency (for example, for MS4623C set to a
		max of 5000 MHz). Can be reset using slider con-
		trol.
		￿ Src 1 Power (dBm):Source 1 power level, in dBm.
		￿ IF Bandwidth (Hz):Intermediate frequency
		value, in Hertz.

5-32 ME 7840A OMM