TX carrier frequency accuracy and current measurement

[DanKA]

Hello, 

my first question is about TX carrier frequency accuracy measurement. The equation given in the whtie papers is 

(|f_measured - f_programmed|) / f_programmed <= M * 10 ^ -6

I measured the carrier frequency on the channels 0, 40 and 80 of the radio_test_example and always got an offset of 6.503 kHz.

Do you expect a constant absolute offset or a constant relative deviation? Because i measured a constant absolute offset, the biggest relative deviation is on channel 0.

My second question is about current consumption. Do you have typically plots for certain events somewhere? I tried to measure the current with an oscilloscope using 5 ohms for R6 on the DKs but struggled, especially with noise and triggering the event correctly. However, these are plots for the nRF51-DK i could measure:

current_measurement.pdf

I do not know how these events should look like. I think, that the values are somewhere in the range they could be be plausible. The tx current @ 0 dBm of the nRF51 is specified with 10.5 mA. What do you think about these plots?

Thank you in advance and kind regards

DanKa

[haakonsh]

Hey DanKA,

6.503 kHz absolute offset is a good result, as expected of a proper design, nothing to worry about there. 

Your measurements looks spot-on:

 

See https://devzone.nordicsemi.com/power/ for more details of the graphs. The number is only valied for the nRF52832, but the detailed information of the different radio states is worth checking out.  

Cheers,

Håkon.