TPM test mode

I am interested in using the TPM test mode (having the TX I/Q data after the PA available in the BBP) but it is not clear to me in what mode exactly it is available and on what port. The reference manual (UG-673) states "It is possible to output TPM I/Q data at the Rx data port in TDD mode in Tx state." on page 61.

My specific questions are:

1. What exactly is the "Rx data port" (in single port TDD mode the P0 data port is used for both TX and RX based on the TXNRX port and port P1 is not used, in dual port TDD mode P0 and P1 are both either TX or RX based on the TXNRX port) so there is not really a dedicated RX port in TDD mode.

2. When in TDD mode and in Tx state, the BBP is driving the digital P0 (or P0 and P1 for dual port mode) port(s). Then how can the I/Q data be available on the "Rx data port" during that time?

3. The additional TPM functionality document in the EngineerZone (https://ez.analog.com/wide-band-rf-transceivers/design-support/w/documents/10058/transmit-power-monitor-tpm-ad936x) states "If the application is TDD, it is not possible to output TPM IQ data on the RX data port as the TDD state machine is overriding the 0x14[D7] bit and is not enabling the Rx port for data transmission. But this is possible in FDD mode, where both the data paths are enabled." This contradicts the statement in the reference manual. Which statement is true? Also, if the document in the EngineerZone is true and TPM test mode is available in FDD mode, how is that possible as in FDD the receive chain is always used for regular receive data (unlike in TDD mode where the receive chain is not used during the tx state so it is available and can be switched to tx mon during that time).

Thank you for your help!

  • If the application is TDD, it is not possible to output TPM IQ data on the RX data port as the TDD state machine is overriding the 0x14[D7] bit and is not enabling the Rx port for data transmission--- This statement from the document is correct. We will update the same in user guide.  

    In FDD mode, you can output the TPM IQ data on the RX data port. For that you have to modify the registers mentioned in the document which will shut down the normal receive path and hence the data that is input to the TPM input will get transferred to the RX data port.