# How can I estimate the minimum baudrate for a given bitrate?

My circuit performs data acquisition at 250 samples/s, 24 bits/sample and transmit this information to the local host (PC) through a bluetooth module that implements the UART protocol.

As far as I know, for each byte transmitted there is 1 start bit, 2 stop bits and 1 parity bit, resulting

(250 samples/s) * (24 bits/sample) / (8 bits/byte) * (12 bits/transmitted byte) = 9000 bits

in 1 second.

Supposing there is one bit per transmitted symbol, the minimum baudrate that would work for this case is 9600 bauds. However, the tests we've performed so far are not convincing, since the received data is contaminated by some enormous jump discontinuities (about 10^13, see figure below).

1. Could you please tell me how I can estimate the minimum baudrate?
2. How would you estimate the baudrate when including the bluetooth module?

• What do you mean by "enormous jump discontinuities"? Is this something you're seeing on an oscilloscope? Or something else? Apr 22, 2019 at 16:45
• The bluetooth module doesn't say in its datasheet? It should. Apr 22, 2019 at 16:53
• Baud rate is not the primary concern here. You need to think about the throughput of the bluetooth link (especially if it needs retries to deal with radio conditions). Your jumps are probably those between bluetooth packets. It's not entirely clear bluetooth is appropriate for your application or which variation of it you are using. Apr 22, 2019 at 18:11
• @scorpdaddy, see attached figure. Apr 23, 2019 at 19:19
• @Toor , I have not seen that information in the BT module datasheet. Anyway, I'll take a look at it again. Apr 23, 2019 at 19:23