Radio transmit power,velocity of transmission and power consumption

[Francesca]

Hi!I work with a Beacon Kit (nrf51822) and I would like to know which is its default radio transmit power and the velocity of transmission. In my application I sent via Ble 120bytes,so how long it takes to send this amount of data? I would like also to estimate the power consumption of CPU using the 32kHz clock. Thanks in advance :)

[FormerMember]

By default, the tx power is 0 dBm. The tx power can be set using sd_ble_gap_tx_power_set(..).

By velocity of transmission, I assume that you mean throughput. The S130 v.2.0.1 supports up to six packets of per connection interval. With connection interval of 7.5 ms and 20 bytes per packet, it is possible to transmit 120 bytes per 7.5 ms. 7.5 ms is the shortest BLE connection interval and 20 bytes is the maximum amount of data per packet.

In order to estimate the power consumption you can start off from the BLE power profiler section in the S130 softdevice specification. The current consumption numbers referred to from that section can be found in the nRF51822 Product Specification.

Note: For development I would recommend you to use the nRF51-DK or the nRF52-DK instead of the beacon kit.

Update 22.06.16: As the BLE power profiler section in the S130 softdevice specification shows, the CPU will only be on for a short amount of time during a connection interval, see the below figure. The figure does only show the first 2500 us of the connection event. The reason is that the chip will be in idle state (connected) the rest of the connection event.

For current consumption of the ADC: The ADC requires 1V2 and HFCLK, see table 33 in the nRF51822 product specification.

[Francesca]

Thank you very much :) May I ask you just a few things about consumption? I don't understand what is I_(cpu,flash): when I have to consider it for the consumption?In my application I use the adc and the transmission principally...I have the I_(cpu,flash) everytime I execute something? and then if my connection interval is 10ms, the beacon consumes 10.5mA (at 0dBm) for the entire interval?

[FormerMember]

I have updated the answer to answer your question.

[Francesca]

Ok thank you, so there is the current I_cpu,flash only at the beginning of the connection right?And the consumption for the transmission of 120bytes lasts for the entire connection interval (7.5ms)?

[FormerMember]

When transmitting 120 bytes = 6 packets x 20 bytes, the transmission part in the figure at the top will occur six times. The transmission part: the part where the radio is being used.