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PER TEST ON SMART RF TRXEB BOARD

Eswaran Rathinam12
Intellectual 350 points
Other Parts Discussed in Thread: CC1120, CC1200

Hello,

          The PER test code,if executed in board,Doesn't consider the Packets received with error right??It just takes the packet and doesn't perform any error check.Because,in the Smart RF studio,if i connect in easy link mode ,and if i remove the antennae in both the boards,it gives a packet error ,whereas in the code,it doesn't.So what has to be done ,if i want to consider the error packets in the code.Please help..Thanks..

  • 0
    TI__Guru* 86241 points

    Hi

    I assume you are asking about the CC1120 PER test? This code is described in the

    “TrxEB RF PER Test Software Example User’s Guide” (http://www.ti.com/lit/swru296).

    BR

    Siri

  • 0 in reply to Siri
    Intellectual 350 points

    Im using cc1200 Module with TRXEB Module kit.The PER Test code displays the number of good packets received.But,if i remove the external antenna connected to SMA connectors,still it receives packets.The number of good packets received is increasing still.I used SmartRF studio and did the same in expert mode.I connected two boards through USB,opened Smart RF Studio,started the communication by enabling one as TX and other one as RX.So,when i remove the antennae in two boards,the RX stops receiving the packets.So that's seems correct.whereas in other case,even when i remove the antennae,it continues to receive packets.So im confused..is there an PCB Printed antenna in the board,so that even when i remove the external antenna's,it receives packets??.Then why the same thing didn't happen when i used smartRF Studio??Please help..Thanks..

  • 0 in reply to Eswaran Rathinam12
    TI__Guru**** 317180 points
    - The CC1200 EMs has PCB antenna. If you look at the board (schematic) you will see that one component could be used to select either the SMA connector or the PCN antenna.
    - Have you looked at the RSSI? Compare this to the sensitivity stated for the different datarates in the datasheet. If you have the board close you will be able to receive without antennas.
    - Are you running with the same RF parameters in the PER test and in SmartRF Studio?
  • 0 in reply to TER
    Intellectual 350 points

    Thanks for answering.But still a small confusion.
    This is what happening.
    1)im running the PER Test code at Easy mode (in board)with Transmit power of 14 Dbm,1.2Kbps,1000 packets.The packets are receiving even after the antennae is removed.Yes,this is because of the Pcb mounted antennae.Thanks..
    2)Im simulating in Smart RF Studio in Easy mode(The easy mode in Smart RF and in PER test code are both same i guess..).So when i remove the antennae again,it continues to receive because of Pcb mounted antennae.
    3)When im simulating in Smart RF Studio in "expert mode" ,the PER stops and the RX doesn't receives any packets(Regardless of whether the configuration in easy mode and expert mode are same-I think it doesn't matter).So even this is good,but what happened to PCB mounted antenna in this mode.Is it getting disabled ??
    In the schematic there is a component numbered R181 between SMA and antennae,So i tried to search the part number in the Table,but i couldn't find it.

    Thanks:)

    This is the schematic file i referred(page no 41): http://www.ti.com/lit/pdf/swra445

  • 0 in reply to Eswaran Rathinam12
    TI__Guru**** 317180 points

    - In easy mode and expert mode you can see what the datarate is.

    - If you look at the schematic the default position of R181 is to select the SMA antenna.

    - expert mode 1.2 kbps: This is covered by quite a few posts: Normally the Tx and Rx side has a delta frequency offset (do a search on Rx BW signal bandwidth ppm). Increase the Rx BW on the receiver until you receive something, with the default RX Bw the delta offset must be close to 0.

  • 0 in reply to TER
    Intellectual 350 points

    Is there a way to disable the PCB printed antennna on the board?

  • 0 in reply to Eswaran Rathinam12
    TI__Guru**** 317180 points
    Not sure if I understand your question since as I pointed out in my previous post the SMA is selected default not the PCB antenna
  • 0 in reply to TER
    Intellectual 350 points

    Thanks,but still confused.

    I used easy mode at smart RF Studio. I removed the antennas connected to SMA connectors.I get the packets received ok.So how is that possible?Then its the pcb mounted antennae which transmits right??So how to disable that?I want to test the module only through SMA antennae. I want to use attenuators,so i need to disable the pcb antennae.Is it possible to do that??Thanks..

    //edit

    I got it.The SMA Antennae is selected by default.The signal from the SMA Connector seems to be good enough for the receiver to receive the packets even when i remove the antennae.So when i moved to a certain distance,The packet error rate increased.

                                          Thanks..