We would like to use the Radio test to do the basick TX/RX test in SDK 15.2
We use the nRF52840-DK for test and follow the CLI document.
1. We use two board (nRF52840-DK) to do the RX test, we follow the below sequence to do RX test.
a. both nRF52840-DK set the channel to "2" (w/ command "start_channel" and 'end_channel"), other parameters keep un-modify.
b. board1 w/ command "start_tx_carrier"
b. board 2 w/ command "start_rx" -> "printf_rx"
But we got below result on board 2, what is the sequence if we need to to RX test.
2. For TX, we would like to measure the tx modulation signal.
We use the command "start_tx_modulated_carrier" to send the signal. We expect to see the packet in the signal, but we only see the continue wave form.
We tried the channel 2402/2442/2480
uart_cli:~$ start_channel 02Start channel set to: 2.uart_cli:~$ parameters_printParameters:Data rate: RADIO_MODE_MODE_Ble_1MbitTX power: RADIO_TXPOWER_TXPOWER_Pos8dBmTransmission pattern: TRANSMIT_PATTERN_RANDOMStart Channel: 2End Channel: 80Time on each channel: 10 msDuty cycle: 50 percentuart_cli:~$ start_tx_modulated_carrier
Thank you, Han
Unfortunately, it is not possible to do a TX/RX communication test with 2 kits using the radio_test example.
The default transmission pattern will be to randomize the RF addresses, so even if they are on the same channel, no payload will be received.
A quick way to test would be to go into radio_test.c::radio_config() and in the case "TRANSMIT_PATTERN_RANDOM", hard-code the NRF_RADIO->PREFIX0 and NRF_RADIO->BASE0 register, then recompile and load the new hex file onto both kits.
The other two transmit patterns are not ideal for actual communication due to the toggling pattern, but you should still receive data even if you choose "TRANSMIT_PATTERN_11001100" or "TRANSMIT_PATTERN_11110000".
1. As changed the pattern to "TRANSMIT_PATTERN_11110000", we can get the data as below.
But what kind of environment setting we can use "TRANSMIT_PATTERN_RANDOM"?
2. For TX, we expect to see the modulated signal, but as follow below setting, we only see the continues signal, is it correct?
Thank you. Han
Hsu said:2. For TX, we expect to see the modulated signal, but as follow below setting, we only see the continues signal, is it correct?
In this mode, you shall see a modulated output, and looking at the screenshots from your spectrum analyzer, the output is modulated. The duty cycle is set to 50 %, which means that the program will transmit every 4 ms (one payload takes ~2 ms with 261 bytes length @1MBit). This might be too fast to be recognized in the spectrum. If you demodulate the data, or look at the input power vs. time, you should see a approximate 50% duty cycle of the RF signal.
This is normally used for compliance testing, as the bit stream should be randomized in most compliance testing programs.
Thank for quick response.
If the duty cycle set to 50 % is too fast to be recognized in the spectrum, how do we set to make the spectrum can recognize?
Because we use below setting, but got below result.
----- setting -----
====== result =========
You can try to use "zero span" to see the power vs. time, where you should then see an approximate duty cycle of 50%.