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E5071B SMC and source power cal questions

Question asked by GW on Oct 9, 2007
Latest reply on Oct 12, 2007 by bhokkan
VNA: E5071B with FOM option (08 I think)
Cal kit: 85033E
DUT: Broadband (nearly the range of the VNA) multi-channel up/down converter with embedded LOs

Background: The DUT has IF limiting in the down converter and RF limiting in the up converter. The primary measurement is limited IF and limited RF power output for a range of IF/RF input levels across multi-octave bands. I'm using the FOM option and full range (300 kHz to 8.5 GHz) source power cal and receiver cal for the absolute measurements but also need to make S11/S22 and gain measurements at a lower power level where the DUT is not in limiting. I performed the scalar mixer cal (SMC) but forgot to turn off source and receiver corrections that were enabled.

Question 1: After the SMC completes and the measurement is switched from B(1) absolute to S21 I expect to see PC (power cal) in the status display in place of P? (power interpolated) but this is not the case. Since the SMC includes source power measurements why doesn't it override the previous source power cal used for absolute measurements?

Question 2: If I turn off source power cal then P? goes blank indicating no source power calibration yet the SMC is still active. Is the power leveled even though it is not indicated as being so? Do I have to perform a separate source power cal over the frequency range of the SMC in order to get non interpolated source calibration? If the answer is yes it seems completely redundant with the SMC which by the way takes a significant amount of time to complete since the power measurements need to be done four times (port 1 F1, port 1 F2, port 2 F1, port 2 F2).

Question 3: Will future firmware revisions include support for Agilent's new series of USB power sensors?

Question 4: Since no one power sensor will cover my full frequency range ( 1 MHz to 8.2 GHz), I compromise on an E9304A (9 kHz to 6 GHz) since use beyond the top end of this sensor has far less error than use below the bottom end of the 10 MHz and up sensors (not surprising). Since it may be too difficult to build a full range sensor it would seem that the VNA should support the concatenation of two sensors for source power cal much the same way as a SOLT cal can utilize multiple cal kits. Any plans for this?

Question 5: The DUT has very wide dynamic range log amps on each channel that need to be checked for transfer function linearity and frequency flatness. The E5071C has auxiliary inputs that would work for this but the B model does not. Does anyone know of a macro that can use the simple ADC on the internal PC sound card for capturing a baseband signal over the VNA's sweep? I’m hoping to avoid any software development.