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Lab Certifications / test-modes / DTM

davman

Any safety-experts that could comment a bit on best ways to prep before send off a nrf51822 equipped battery-powered consumer-device to the lab for regulatory certifications.

We use a module that already have:

  • FCC Part 15 Subpart C
  • EN300328

And safety lab want's to do:

  • CE RF_EN300328(RSE+output power)
  • FCC EMC Part 15B
  • CE EMC_EN301489-1-17
  • CE LVD_EN60950-1

To to this, they want us to prep code to run

  • CH1, 21, 40 @ 60~70% duty cycle and various TX power.
  • Hopping Mode 1 to 40

So... my questions are:

  • Does these tests sound reasonable, and the rf-tests required to run, are these all relevant for BLE?
  • Without knowing much about DTM, I assume this be done using DTM + a simple SD & UART setup? If not, are there any nordic example projects to help prep for cert?
  • 0

    Hi,

    I have recently setup units for testing at the lab. You will need to send them standard units with FW that will be shipped with the unit. You might also need to provide equipment that uses the link so that all functions are on (with the most EMC/I generated).

    Because your product is an intentional radiator, and the module has other HW around it, or different antenna connections layout, the transmitter and receiver (for local oscillator emissions) RF need to be remeasured. Depending on what the lab requires you might need to supply a unit with a test coax on the 50ohm point of the antenna output also for conducted RF tests.

    DTM (Direct Test Mode) is a stand interface for Bluetooth test tools to perform RF PHY tests, but is also most convenient to implement a test setup for your lab that enable continuous Tx/Rx on tests. See Volume 6, Part F of the BT4 core spec for more DTM protocol info.

    The easiest way for you to set up these units is to build the DTM example project, load the RF test units with that and wire up a USB to 232 TTL cable to your UART pins. You could give the lab nRFgo Studio as the PC end interface to DTM or write your own PC app.

    I've included DTM in my product apps to enable PCBA RF Tx tests in the factory, which is also based on the example.

    Simon

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