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nRf51422 data rates

Paul

Hi, I'm having the purpose to use nRF51422 /ANT to connect a relatively data hungry ANT device. The nRf51422 specs expose three programmatically available data rates : 250 kbps, 1Mbps, 2 Mbps. I'm unable to find more details in the doc (either soft device 310 or product reference manual) Could you tell me where I can find details concerning the data rates options Regards

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    [continuing the previous comment]

    You transmit the data 10 times a second. For a "classic" way of transmission, you need 90 bits each second. Now you will assume that the physical limitation of the temperature sensor is that the temperature can't change more than 1°C/100 miliseconds. So, you will send only the increments - two bits (you need to implement three states -1; 0; 1). You reduced the data rate to 20 bits/second - cool, isn't it?

    Yes, but there are some problems. For example - you will lose a packet. You can't reconstruct the data anymore. OK, you will send the absolute value once a second. Voila - 9 bits + 10*2 bits = 29 bits => about 33% data rate of the "normal" way.

    This example is very simplified, it does not include any packet structure etc. Just for illustration of how the data compression can work. The robust implementation itself is much harder.

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  • 0

    [continuing the previous comment]

    You transmit the data 10 times a second. For a "classic" way of transmission, you need 90 bits each second. Now you will assume that the physical limitation of the temperature sensor is that the temperature can't change more than 1°C/100 miliseconds. So, you will send only the increments - two bits (you need to implement three states -1; 0; 1). You reduced the data rate to 20 bits/second - cool, isn't it?

    Yes, but there are some problems. For example - you will lose a packet. You can't reconstruct the data anymore. OK, you will send the absolute value once a second. Voila - 9 bits + 10*2 bits = 29 bits => about 33% data rate of the "normal" way.

    This example is very simplified, it does not include any packet structure etc. Just for illustration of how the data compression can work. The robust implementation itself is much harder.

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