scanning waveform

[snow]

Hi, all. I use nrf51822 complete to scan devices, with nRF51_SDK_10.0.0 and s120_nrf51_2.1.0. When in scan state, the scan window is 50ms, and scan interval is 100ms. I get the scanning waveform of the scanner, and I found the scanning waveform is strange. In "pic1", I found in scan window, the voltage is down and up, not a straight line. And I extend one scan window, such as "pic2". In "pic2", the voltage down, and a little time later the voltage restores. This situation happen 7 times. Why this situation happen? Is there something happen?

pic1:

pic2:

[Einar Thorsrud]

Can you provide some more information about what and how you are measuring?

[snow]

I'm measuring the voltage of PCA10006 working voltage, when in scan state. And the program is ble_app_multilink_central. And the high level in "pic1" is scanning window, the low level in "pic1" is not scan window. In "pic2", just to show "pic1" scan window, just extending "pic1" high level(scanning window).

[Einar Thorsrud]

The dips you see in power consumption is post processing of a received advertisment packet being performed (stage F in this table).

The scanning event power profile in the SoftDevice specification is inaccurate, as it shows post processing only in the end of the scan interval. However, once a advertisement packet is received the post processing will be performed. Once post processing is done the radio will go back to RX mode again, as long as there is enough time left in the scan window. However if performing active scanning, a scan request packet may be sent instead (taking more time with additional stages like radio turnaround, TX etc.).

[snow]

OK, Thank you very much. I get it.

[Einar Thorsrud]

I'm glad to hear. If you are happy with the answer I would appreciate it if you could accept it by clicking the circle checkmark to the left of it.