Is it feasible to transmit 16bit 16KHz PCM audio via Nrf52840?

RE: Is it feasible to transmit 16bit 16KHz PCM audio via Nrf52840?

David Edwin — Wed, 24 Apr 2019 14:15:16 GMT

Example used for measurements:
nRF5_SDK_15.2.0_9412b96\examples\ble_central_and_peripheral\experimental\ble_app_att_mtu_throughput

Connection interval: 23.75ms
Packet size: DLE : 251 bytes
On air encoding: 1Mbps
Time taken to transfer 1Mbyte from nRF52840 peripheral to central : ~12.9 seconds (approximately 650kbps)
Packets lost to CRC errors : 0

Looks like DLE is required at a minimum as a 27 byte RF packet seems to be too small for the 256kbps bandwidth.
2Mbps on air will be better but the number of phones supporting 2Mbps on air will be smaller.
connection intervals like 23.75ms performed better than connection intervals like 7.5ms, likely due to more large packets fitting in an longer connection interval.

The closest example for microphone integration would be the Smart Remote 3 reference design.

See the code and documentation here.
Caveat: the Smart remote 3 uses an older SDK version and you will need to upgrade it to get it to work with the latest SDK version.

RE: Is it feasible to transmit 16bit 16KHz PCM audio via Nrf52840?

BK — Wed, 24 Apr 2019 10:25:27 GMT

Hi Amanda, thank you so much for your quick response :)

Is the "USB Audio Class Example" is to use a cable connection to transmit the audio?

My case it to transmit he realtime voice captured by microphone on my circuit board to an mobile phone via bluetooth.

RE: Is it feasible to transmit 16bit 16KHz PCM audio via Nrf52840?

Amanda Hsieh — Wed, 24 Apr 2019 08:47:01 GMT

Hi,

This USB Audio Class Example is close to your requirement.

Best regards,

Amanda