ADRV9002 used for measuring scattering parameters

Question

Hi, 
 I am planning to use ADRV9002 for setting up an instrumentation that can measure scattering parameters. S11 and S21. For this I need three receivers (V1+, V1-, V2-) to be able to calculate S11 and S21. 
 question: 1) From the datasheet I understand there are Rx1 and Rx2. However, what is the difference in Rx1A and Rx1B? is it multiplexed and simultaneously be used to to demodulate/receive the same carrier frequency? since I only have two receivers, would I need another transceiver chip? question: 2) the power level of the Tx, does it have to be calibrated with a loopback? and after calibration would it be stable? 
 question: 3) could the V1+ be obtained with the internal loop back? I understand it uses one of the receivers? 
 question: 4) on page 112 of UG-1828, "Transmitter NCO internal Signal Source"--> can this feature be used as the source/input signal for this type of measurement? Some more elaboration on how will be very helpful.

yhkim · Accepted Answer

It is not possible to use Rx1B in that way. ILB is used only for internal calibration algorithm and not available to user. You can use MCS feature to synchronize the second chip so that both of the chips have the same deterministic latency. Whether to use synchronization depends on your system requirement. Without MCS, the latency of two chips will not be same, but the difference stays same once the chip is initialized and calibrated. Yes, you can use two evaluation board and synchronize them)

yhkim · Answer

1. You can use either RX1A or RX1B, only one at a time. It is multiplexed and you can switch it through API. You would need more than one chip if your application require more than two channels running simultaneously. . 
 2. Power level is stable, but only the typical value is specified in the data sheet. Internal loopback is used only for internal calibration algorithm, and not available to user. 
 3. It'd be appreciated if you could clarify your question. The specified transmit power is the power delivered to 50 ohm load, which can be measured with an instrument. 
 4. You can use internal NCO a signal source in the transmit path. You may an option to use NCO instead of tone generated by FPGA. You can enable it using the TES GUI tool: [main menu] -> [Configure] -> [Radio] -> [ Transmit Data Source] -> [Use internal tone generation] 
 I suppose you need some kind of bridge to isolate forward and reflected power if you want to realize a network analyzer along with ADRV9002. 
 Hope this answer your question.

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ADRV9002 used for measuring scattering parameters

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