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WL1837MOD: Rx spurious emissions failure

Jennifer Liu
Prodigy 150 points
Part Number: WL1837MOD

Hello,

There is a high 2nd harmonic that is looking marginal compared to the EN 300 328 Rx spurious emission limits. We verified this conducted on the eval board and confirmed the 2nd harmonic when it is set to Rx in Awake mode in the RTTT software. When in 'Listen' mode, the emission disappears. Can you clarify the difference and which mode it should be set for Regulatory purposes. In our test, we have been using the test scripts to set to RX mode (processors.wiki.ti.com/.../WL18xx_RX_Testing) and also observe the failing 2nd harmonic. Are the below the correct set of test scripts to set to Rx mode for regulatory test? We also evaluated this radiated and accounted for antenna gain and cable losses, we also observe the 2nd harmonic failing in Rx mode. Can you advise.

The first analyzer plot shows the 2nd harmonic in Rx mode using the RTTT software and the second analyzer plot shows the 2nd harmonic in Tx mode as a comparison.

Scripts executed to set Rx to Channel 1:

calibrator tiw_sta0 plt power_mode on'

calibrator tiw_sta0 wl18xx_plt tune_channel 1 0 0'

calibrator tiw_sta0 wl18xx_plt start_rx 00:11:22:33:44:55 11:22:33:44:55:66'

calibrator tiw_sta0 wl18xx_plt get_rx_stats'

Conducted Rx emission plot of 2nd harmonic using development board:

Conducted TX emission on 2nd harmonic (As comparison)

 

  • 0
    TI__Genius 12740 points
    Hi Jennifer,

    Sorry to here you are having this issue. A few follow up questions and some additional information needed:

    1) Are you using a single antenna configuration or dual antenna configuration?
    2) When using RTTT this is the gui interface with the PC and does not use the host. Can you provide the .INI file version that you are using
    3) When you use calibration this is with the host. Did you go thru the configuration to set up the device properly? Can you provide the output / sequence of what you are doing here.

    The issue does sound like a simple set up issue. So lets start with the above and we can go from there.

    Thanks,
    Riz
  • 0 in reply to Rizwan Murji
    Prodigy 150 points

    https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/968/tiwlan.ini

    Fullscreen PLT_command_and_responses.txt Download 
    sh /etfs/comm/bin/startWifiDrivers.sh
wpa_supplicant v2.1-devel
Successfully initialized wpa_supplicant
Initializing interface 'tiw_sta0' conf '/etfs/comm/etc/wpa_supplicant_ti18xx.conf' driver 'wilink' ctrl_interface 'N/A' bridge 'N/A'
Configuration file '/etfs/comm/etc/wpa_supplicant_ti18xx.conf' -> '/etfs/comm/etc/wpa_supplicant_ti18xx.conf'
Reading configuration file '/etfs/comm/etc/wpa_supplicant_ti18xx.conf'
update_config=1
ctrl_interface='/var/run/wpa_supplicant'
ap_scan=1
device_name='TI_Wilink8'
manufacturer='TexasInstruments'
model_name='TI_Connectivity_module'
model_number='tiwlan_drv'
serial_number='12345'
p2p_disabled=1
config_methods='virtual_display virtual_push_button keypad'
HOSTAPTIW wilink_global_init: enter
HOSTAPTIW wilink_if_init: enter ifname = tiw_sta0 
HOSTAPTIW wilink_if_init: Ctrl_If = /dev/tiw_sta_ctrl 
 HOSTAPTIW : driver capabilities: key_mgmt 0x6f enc 0xf flags 0x90626a40
HOSTAPTIW wilink_if_init: assigned driver role 1 to the interface
In prepare_enable_role_buff- roleType : 1, bindir : /etfs/data/wifi_local// 
HOSTAPTIW wilink_toggle_events: enter role = 1 mode = 115
Add interface tiw_sta0 to a new radio N/A
HOSTAPTIW tiwdrv_get_hapd_handle: hapd handle is NULL!!!
tiw_sta0: Own MAC address: 40:bd:9e:00:2f:8c
HOSTAPTI wilink_set_key: enter
HOSTAPTI wilink_set_key: enter
HOSTAPTI wilink_set_key: enter
HOSTAPTI wilink_set_key: enter
tiw_sta0: RSN: flushing PMKID list in the driver
tiw_sta0: State: DISCONNECTED -> INACTIVE
WPS: Set UUID for interface tiw_sta0
WPS: UUID based on MAC address - hexdump(len=16): b9 3c e5 10 89 5c 58 f3 aa ff 0b 51 21 b2 0d 8a
EAPOL: SUPP_PAE entering state DISCONNECTED
EAPOL: Supplicant port status: Unauthorized
EAPOL: KEY_RX entering state NO_KEY_RECEIVE
EAPOL: SUPP_BE entering state INITIALIZE
EAP: EAP entering state DISABLED
EAPOL: Supplicant port status: Unauthorized
EAPOL: Supplicant port status: Unauthorized
tiw_sta0: Added interface tiw_sta0
tiw_sta0: State: INACTIVE -> DISCONNECTED
wilink_set_operstate: operstate 0->0 (DORMANT)
Daemonize..
WPA supplicant started
[08:01:30] AltOS / # wpa_cli_ti18xx terminate
Selected interface 'tiw_sta0'
OK
[08:01:34] AltOS / # cd /etfs/devel/bin
[08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 plt power_mode on

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load hostapd configuration file %s
: No such file or directory

Failed to load hostapd configuration file 

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load wpa supplicant's P2P configuration file %s
: No such file or directory

Failed to load wpa supplicant's P2P configuration file \zzc
[08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt tune_channel 1 0 0

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load hostapd configuration file %s
: No such file or directory

Failed to load hostapd configuration file 

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load wpa supplicant's P2P configuration file %s
: No such file or directory

Failed to load wpa supplicant's P2P configuration file \zzD
�bhannel tune of channel 1 was performed OK
[08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt start_rx 00:11:22:33:44:55 11:22:33:44:55:66

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load hostapd configuration file %s
: No such file or directory

Failed to load hostapd configuration file 

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load wpa supplicant's P2P configuration file %s
: No such file or directory

Failed to load wpa supplicant's P2P configuration file \zzR
RX Simulation started OK (Note that statistics counters are being reset).
[08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt get_rx_stats

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load hostapd configuration file %s
: No such file or directory

Failed to load hostapd configuration file 

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load wpa supplicant's P2P configuration file %s
: No such file or directory

Failed to load wpa supplicant's P2P configuration file \zz

�qX statistics (status 0)
Total Received Packets: 9
FCS Errors: 0
MAC Mismatch: 9
Good Packets: 0
Average RSSI (SOC): 0
Average RSSI (ANT): 0
PER:1.000000     # PER = Total Bad / Total Received
[08:01:40] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt stop_rx

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load hostapd configuration file %s
: No such file or directory

Failed to load hostapd configuration file 

Error while opening config file! 

Error opening file
: No such file or directory

Failed to load wpa supplicant's P2P configuration file %s
: No such file or directory

Failed to load wpa supplicant's P2P configuration file \zz��
Rx Simulation Stop was OK
    Hi Riz,

    To answer your questions:

    1. I tested in single antenna configuration

    2. For RTTT mode, see attached INI file

    3.  For test in Calibrator mode, it appears that the device was configured properly. See attached text showing a log of executed commands and acknowledgements. 

    thanks,

    Jennifer

  • 0 in reply to Jennifer Liu
    TI__Genius 12740 points
    Hi Jennifer,

    Looking at the txt file you send I see a lot of errors with the config file (Error, failed to load), so I cannot confirm that it has been loaded properly.

    Having said that, the limit for receiver spurious is -47dBm for frequencies between 1 Ghz and 12.75 Ghz. thus the levels you are showing do not seem to be failing. The correct method is to use the radio with calibrator and the RX script you are using. Or RTTT as well. In either case looking at your data against the -47dBm limit (even after accounting for antenna gain, you have enough margin to the limit. The higher limit of -57 is 10dB margin to the spec, which is in-line with what we expect.

    I hope this helps.
    Thanks,
    Riz
  • 0 in reply to Rizwan Murji
    Prodigy 150 points

    Thanks Riz.

    1. Can you point to which error message that shows it’s not loading properly? What is the correct acknowledgement we should be seeing?
    2. After executing PLT mode, what response or acknowledgement should appear that shows it is running properly?

    Jennifer

  • 0 in reply to Jennifer Liu
    TI__Genius 12740 points
    Hi Jennifer,

    In the PLT command and response.txt file that you uploaded I see the following:

    -----
    Error opening file
    : No such file or directory

    Failed to load hostapd configuration file %s
    : No such file or directory

    Failed to load hostapd configuration file

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file %s
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file \zzc
    [08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt tune_channel 1 0 0

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load hostapd configuration file %s
    : No such file or directory

    Failed to load hostapd configuration file

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file %s
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file \zzD
    …bhannel tune of channel 1 was performed OK
    [08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt start_rx 00:11:22:33:44:55 11:22:33:44:55:66

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load hostapd configuration file %s
    : No such file or directory

    Failed to load hostapd configuration file

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file %s
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file \zzR
    RX Simulation started OK (Note that statistics counters are being reset).
    [08:01:39] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt get_rx_stats

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load hostapd configuration file %s
    : No such file or directory

    Failed to load hostapd configuration file

    Error while opening config file!

    Error opening file
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file %s
    : No such file or directory

    Failed to load wpa supplicant's P2P configuration file \zz
    -----

    Once you enter the commands for transmission I would expect no error messages.

    Thanks,
    Riz
  • 0 in reply to Rizwan Murji
    Prodigy 150 points

    Hi Riz,

     

    We were able to correct the error messages. Attached is New Rx Script log file:

    Fullscreen Rx script log file.txt Download 
    [08:00:36] AltOS / # sh /etfs/comm/bin/startWifiDrivers.sh

wpa_supplicant v2.1-devel
Successfully initialized wpa_supplicant
Initializing interface 'tiw_sta0' conf '/etfs/comm/etc/wpa_supplicant_ti18xx.conf' driver 'wilink' ctrl_interface 'N/A' bridge 'N/A'
Configuration file '/etfs/comm/etc/wpa_supplicant_ti18xx.conf' -> '/etfs/comm/etc/wpa_supplicant_ti18xx.conf'
Reading configuration file '/etfs/comm/etc/wpa_supplicant_ti18xx.conf'
update_config=1
ctrl_interface='/var/run/wpa_supplicant'
ap_scan=1
device_name='TI_Wilink8'
manufacturer='TexasInstruments'
model_name='TI_Connectivity_module'
model_number='tiwlan_drv'
serial_number='12345'
p2p_disabled=1
config_methods='virtual_display virtual_push_button keypad'
HOSTAPTIW wilink_global_init: enter
HOSTAPTIW wilink_if_init: enter ifname = tiw_sta0
HOSTAPTIW wilink_if_init: Ctrl_If = /dev/tiw_sta_ctrl
HOSTAPTIW : driver capabilities: key_mgmt 0x6f enc 0xf flags 0x90626a40
HOSTAPTIW wilink_if_init: assigned driver role 1 to the interface
In prepare_enable_role_buff- roleType : 1, bindir : /etfs/data/wifi_local//
HOSTAPTIW wilink_toggle_events: enter role = 1 mode = 115
Add interface tiw_sta0 to a new radio N/A
HOSTAPTIW tiwdrv_get_hapd_handle: hapd handle is NULL!!!
tiw_sta0: Own MAC address: 3c:a3:08:a6:ff:16
HOSTAPTI wilink_set_key: enter
HOSTAPTI wilink_set_key: enter
HOSTAPTI wilink_set_key: enter
HOSTAPTI wilink_set_key: enter
tiw_sta0: RSN: flushing PMKID list in the driver
tiw_sta0: State: DISCONNECTED -> INACTIVE
WPS: Set UUID for interface tiw_sta0
WPS: UUID based on MAC address - hexdump(len=16): 03 f0 f6 b9 d3 b0 5f 63 83 33 fa 1f 2a 21 51 27
EAPOL: SUPP_PAE entering state DISCONNECTED
EAPOL: Supplicant port status: Unauthorized
EAPOL: KEY_RX entering state NO_KEY_RECEIVE
EAPOL: SUPP_BE entering state INITIALIZE
EAP: EAP entering state DISABLED
EAPOL: Supplicant port status: Unauthorized
EAPOL: Supplicant port status: Unauthorized
tiw_sta0: Added interface tiw_sta0
tiw_sta0: State: INACTIVE -> DISCONNECTED
wilink_set_operstate: operstate 0->0 (DORMANT)
Daemonize..
WPA supplicant started
[08:02:33] AltOS / # wpa_cli_ti18xx terminate
Selected interface 'tiw_sta0'
OK
[08:02:37] AltOS / # cd /etfs/devel/bin
[08:02:42] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 plt power_mode on
[08:02:42] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt tune_channel 1 0 0
Channel tune of channel 1 was performed OK
[08:02:43] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt start_rx 00:11:22:33:44:55 11:22:33:44:55:66
RX Simulation started OK (Note that statistics counters are being reset).
[08:02:43] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt get_rx_stats

RX statistics (status 0)
Total Received Packets: 2
FCS Errors: 1
MAC Mismatch: 1
Good Packets: 0
Average RSSI (SOC): 0
Average RSSI (ANT): 0
PER:1.000000     # PER = Total Bad / Total Received
[08:02:43] AltOS /etfs/devel/bin # ./calibrator tiw_sta0 wl18xx_plt stop_rx
Rx Simulation Stop was OK

    Can you confirm from the logfile that it was executed properly? We still observe the 2nd harmonic after correcting the error messages.

    thanks,

    Jennifer

  • 0 in reply to Jennifer Liu
    TI__Genius 12740 points
    Hi Jennifer,

    Yes it seems things loaded ok now. As mentioned earlier, I do expect to see a 2nd harmonic, but based on your previous data it is within the expectation.

    Thanks,
    Riz
  • 0 in reply to Rizwan Murji
    Prodigy 150 points

    Thanks for confirming Riz.

    Regarding the second harmonic:

    1) It Is unusually high for receive mode. In fact, the emission level is comparable to the 2nd harmonic level in Tx mode.

    2) It is failing the ETSI limit with antennas from TI's certified list. We are using antenna part number (Ethertronics 1000423)

    3) In TI’s ETSI report, there  is no 2nd harmonic observed in radiated or conducted Rx mode. It's in Page 43-44 of the EN 300 328 WLAN report.

    Thanks,

    Jennifer

  • 0 in reply to Jennifer Liu
    TI__Genius 12740 points
    Hi Jennifer,

    Can you provide a figure of how you have the test setup? I would like to confirm what the test setup looks like.

    Thanks,
    Riz
  • 0 in reply to Jennifer Liu
    TI__Genius 12740 points
    Hi Jennifer,

    Thanks for the set up. Perhaps I am missing something here, but why do you feel you are failing the test? Your measured data in RX is showing -64dBm? When you have the radio in "listen mode", do you get similar to plots to what is in our reports? Are you working with a lab at the moment or is this internal testing.

    Thanks,
    Riz
  • 0 in reply to Rizwan Murji
    Prodigy 150 points

    Hi Riz,

    1. It is a radiated Rx emissions failure based on testing done at an external lab.
    2. However, yes, that is correct, it is passing conducted Rx emissions at the -47dBm limit.
    3. When I test the radio in “listen mode” using RTTT and the TI Eval Board, I see the 2nd harmonic offset by 10MHz. E.g. when we have Rx tuned to 2412MHz and set to ‘listen mode’, we see an emission at 4834MHz which is equal to the 2nd harmonic+10MHz. When set to "awake" mode, the 2nd harmonic appears and is emitting at 4824MHz at a similar level. Both emissions whether in "listen" or "Awake" mode are failing radiated. Comparing this to the TI reports, the TI reports have no harmonics or emissions similar to what we are seeing in the receive mode.

    thanks,

    Jennifer

  • 0 in reply to Jennifer Liu
    TI__Genius 12740 points
    Hi Jennifer,

    Have you resolved your issue? Can you provide me a plot of your radiated emissions for review?

    thanks,
    Riz
  • 0 in reply to Rizwan Murji
    Prodigy 150 points

    Please see attached word document for test results from the 3rd party lab. You will find a comparison of Tx and Rx spurious emission plots as well as a maximization plot of the 2nd harmonic for Rx spurious emissions for 802.11b.

    802.11b Rx and Tx Spurious Emissions plots.docx