TX/RX question of Radio test of SDK 15.2

[Hsu]

Hi Sir,

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 02
Start channel set to: 2.
uart_cli:~$ parameters_print
Parameters:
Data rate: RADIO_MODE_MODE_Ble_1Mbit
TX power: RADIO_TXPOWER_TXPOWER_Pos8dBm
Transmission pattern: TRANSMIT_PATTERN_RANDOM
Start Channel: 2
End Channel: 80
Time on each channel: 10 ms
Duty cycle: 50 percent
uart_cli:~$ start_tx_modulated_carrier

----

Thank you, Han

[Hsu]

Hi Håkon,

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?

uart_cli:~$ start_channel 02
Start channel set to: 2.
uart_cli:~$ parameters_print
Parameters:
Data rate: RADIO_MODE_MODE_Ble_1Mbit
TX power: RADIO_TXPOWER_TXPOWER_Pos8dBm
Transmission pattern: TRANSMIT_PATTERN_RANDOM
Start Channel: 2
End Channel: 80
Time on each channel: 10 ms
Duty cycle: 50 percent
uart_cli:~$ start_tx_modulated_carrier

 

Thank you. Han

[Håkon Alseth]

Hi,

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.

But what kind of environment setting we can use "TRANSMIT_PATTERN_RANDOM"?

This is normally used for compliance testing, as the bit stream should be randomized in most compliance testing programs.

Kind regards,

Håkon

[Hsu]

Hi Håkon,

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 -----

uart_cli:~$ start_channel 02
Start channel set to: 2.
uart_cli:~$ parameters_print
Parameters:
Data rate: RADIO_MODE_MODE_Ble_1Mbit
TX power: RADIO_TXPOWER_TXPOWER_Pos8dBm
Transmission pattern: TRANSMIT_PATTERN_RANDOM
Start Channel: 2
End Channel: 80
Time on each channel: 10 ms
Duty cycle: 50 percent
uart_cli:~$ start_tx_modulated_carrier

--------------------

====== result =========

====================

[Håkon Alseth]

Hi,

 

You can try to use "zero span" to see the power vs. time, where you should then see an approximate duty cycle of 50%.

Kind regards,

Håkon