Radio Test clarification

[ble_alex]

I'd like to better understand 2 aspects of the Radio Test example.  My apologies if this is a repost, but I wasn't able to find complete answers elsewhere in the forum.

1. When performing a modulated TX carrier test, will the test continue indefinitely after calling "radio_modulated_tx_carrier(txpower_, mode_, channel_start_);" or is it necessary to restart the modulated transmission periodically? If a restart is necessary, is there a way to poll when the current transmission has finished, and what is the typical duration for a given transmission?

2. If the modulated TX carrier test does continue indefinitely, are there breaks in the data transmission, or is data transmitted continuously?  If there are breaks, are they characterized? For example if I call  "radio_modulated_tx_carrier(RADIO_TXPOWER_TXPOWER_Pos4dBm, RADIO_MODE_MODE_Nrf_2Mbit, 0)" does the radio transmit at x% duty cycle with period of 7 msec (what are the values of x and y)?

This is for radio emissions testing where the testing facility has asked for the module to transmit continuously at max power with a modulated signal.

Thanks for the help,

[Andreas]

Hi,

 

1. Unless you send a stop command(or do nothing), the test will continue indefinitely, no restart i needed.

2. The modulated TX carrier test sets the following shorts

NRF_RADIO->SHORTS     = RADIO_SHORTS_END_DISABLE_Msk | RADIO_SHORTS_READY_START_Msk | \
                            RADIO_SHORTS_DISABLED_TXEN_Msk;

Which basically makes the radio automatically start transmitting a packet when it is ready (RADIO_SHORTS_READY_START), automatically disable when the packet has been transmitted (RADIO_SHORTS_END_DISABLE) and automatically enable TX when it has been disabled (RADIO_SHORTS_DISABLED_TXEN). This keeps the radio constantly shutting down, and starting back over again. I do not know the numbers off the top of my head, but time spent transmitting the packet is 1-2 ms (2Mbps and 1 Mbps, respectively), time spent between the end of one packet and the start of the next one is ~40 µs. This should give ~98% duty-cycle, or thereabout.

You could probably increase the duty-cycle even more by instead of RADIO_SHORTS_END_DISABLE set RADIO_SHORTS_END_START to have the radio immediately go into transmitting another packet once one is finished, without having to disable the radio. You should confer with the test facility before doing so though, as they might want to make sure there is no spur or effects during enable/disable.

 

Best regards,

Andreas