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Mixer Pulse High Power Measurements

Question asked by LOlson on Aug 29, 2007
Latest reply on Jan 30, 2008 by danielrigano
This is a long post but I have a complicated test to setup.
I have been creating/supporting automated SMC tests on CW downconverters for a while but I need to develop a automated test for a receiver/transmitter module that has both a upconverter and downconverter. The downconverter only requires -30 dBm max and has a maximum of 44 dB gain. The upconverter requires a maximum of +19 dBm input and has a 2dB compression point of  33.5 dBm max. The LO signal is common to both converters and the RF port is common – there is a internal circulator at the port that feeds the RF input to the downconverter circuit and feeds the upconverter output to the port. The downconverter only requires CW tests but the upconverter requires pulsed measurements with a 100 us pulsewidth and 10% duty cycle. Among the required tests are amplitude and phase ripple measurements using 801 frequency points. I am going to be using a Z5623A option 83 pulse test set for the first time with our E8364B PNA which has options UNL, 014, 080, 081, 083, H08, H11 and UNL. I am trying to determine the required external equipment and the most efficient setup (by the way, the test set has a RF switching panel that takes the PNA ports 1 and 2 and connects them each to 1 of 4 ports). I am planning to use the Z5623A port 1 circuit in the bypass mode for the downconverter tests and in the Pulse High Power mode for the upconverter. From some of the other posts I have read, I believe I will need to do both SMC and VMC cals for the downconverter and for the upconverter. Here are some questions I have:
1) For the VMC mode I normally need a mixer inserted between the Reference 1 Source Out and RCVR R1 IN but not for the SMC mode. As I am using the Z5623A I believe I need to insert it between the Z5623A RCVR R1 Out and PNA RCVR R1 In and use the option 081 transfer switch to switch between VMC/SMC modes. Will that work?
2) For the upconverter tests I believe I need isolators connected to the Source Out to CPLR THRU ports on at least the port 1 circuit of the Z5623A. The Z5623A Figure 13 suggests that I also need one on the port 2 Source Out to CPLR THRU ports. They must be rated for the entire frequency range from the IF frequency to the highest RF frequency for calibration purposes, correct? If I need it on the port 2 circuits does that mean I need to set the Z5623A to High Power Mode for Port 2? It is difficult to find an isolator that meets the frequency range and has decent isolation. The IF is about 2.9 GHz and the RF range is 6-12 GHz.
3) The amplifier I am ordering to meet the upconverter input power requirement must meet the same frequency requirement for calibration as well, correct?
4) I have 6-10 dB loss between the UUT and the VNA Port 2 at the RF frequencies so I expect to have less than +28 dBm peak at all frequencies and I will only be operating 10% duty cycle so I believe I am safe as far as the PNA is concerned. I also believe I am safe as far as the Z5623A goes because it has much higher limits as long as I don’t apply the amplifier power while switching paths within the Z5623A. I can add an attenuator to the port 2 cable but as I also need to do VSWR measurements to all of the UUT ports, I don’t want to add any additional attenuators I don’t need. Any comments on what I need to watch out for?  

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