AD9371/AD9375 Observation and Snipper Rx simultaneously

Hi,

We are planning to use AD9371/AD9375 for One Transmitter (TX1) with ORx1 alone. Whereas we are not going to use TX2 and ORx2.

Also we are planning to use one Sniffer Rx channel for monitoring radio activities.

In your UG-992 manual a Note was given "that only one input channel of the ORx inputs can be active at any time".

Is it possible to use one ORx1 and one Sniffer Rx channel simulataneously?

How many ADC's are there in AD9371/75 for ORx and Sniffer Rx channels?

  • Hi,

    In that case, I will use different LO's (TxLO for ORX1 path and SnRx LO to Sniffer Rx path) for ORx and SnRx operation.

    We will switch b/w ORX1 and SnRx during operation to do the DPD/calibration in ORX1 path as well as radio activity monitoring in SnRx path.

    As per UG-992 page No: 172 (Figure 88. Simplified Block Diagram of the ORx Front End) I/Q MUX SWITCH to used for switching b/w ORx1 and SnRx.

    What will be the typical switching and settling time for I/Q MUX SWITCH to switch b/w ORx1 and SnRx path?

    Is there any impact in AD9375 DPD performance during switching the ORx path to SnRx path and comeback to ORx path?

    Is there any mode available in AD9375 during DPD, To safely switching b/w ORx path to SnRx path and comeback to ORx path?

  • 2ORx and 3 Sniffer share same ADC. Hence they need to be time shared and cannot be used simultaneously.

  • Thanks for your clarification, It really useful for our design effectively using AD9371/75.

    We are planning to monitor radio activity in one of the bands (1 to 3GHz) and another band (4.0 to 5.2GHz) and we try to simulate the S-parameter files given in AD9375 design package to check which SnRx path (A or B or C) suitable for our bands.

    But we are not able to get return loss in 50Ohms/400 Ohms input termination in A, B and C ports which is attached FYR.

    1. May I know the SNRx A, B & C ports frequency band supported and how the S-parameter files are taken?

    2. Also in your datasheet page No: 57, It was mentioned as "The sniffer channel is also limited to operation from 300 MHz to 4000 MHz. Performance cannot be guaranteed for LO settings above 4000 MHz". What could the performance limitations expected over 4000MHz whereas we have one band in 4.0 to 5.2GHz. Is It same for ORx path also or only for SnRx path alone?

  • Yes you can use Tx Lo for ORx path and sniffer LO for sniffer path and switch between them.

    ORx path is used for tracking calibrations as well and you need to allocate slots with minimum 800Usec for running tracking calibrations. Arm controls the priority of calibrations and it runs automatically when ORx path is assigned for internal cals.

    If using AD9371 you need to allocate 3 slots , one for internal cals , one for external DPD and one for Sniffer.

    Typical enable to ack time is 3 usec. 

    If using AD9375 , DPD is part of internal tracking cal  and arm takes care of scheduling.If slots with 800Usec is provided for cals DPD should not be impacted because of switching to Sniffer.

  • 1. Sniffer receivers operate form 300 MHz to 4000 MHz. Please refer UG-992 section on SERIES AND PARALLEL IMPEDANCE MODELS for details on model used. Hope you have seen 2 subfolders under AD9371_s-parameter_models folder.

    2. The datasheet specifications are met only in the frequency band mentioned in datasheet. We do not have data beyond what is specified in datasheet. 

    ORx path is different it supports frequency range from 300 to 6000 MHz , it does not contain LNA where as Sniffer contains LNA and AGC.