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Why RF_Test examples have 0 to 80 channels

David_Kim

HI

In the RF_Test example, there are 80 channels.

However, BLE has only 40 actual channels.

Why are there 40 channels...? I would like to know.

Do 80 channels cover the frequencies of 40 BLE channels?

thank.

Parents
  • +1

    Hi,

    The Radio test sample is used for testing the Radio it is not explicitly made to test BLE. The 80 channels cover the radio span and also covers all 40 BLE channels. Bluetooth data channels are spaced 2MHz apart and are each 2MHz wide and the three advertising channels in the 2.4GHz band with center frequencies at 2402MHz, 2426MHz, and 2480MHz

    In radio test the channel 02 will be 2402MHz, channel 30 is 2430MHz and so forth. 

    Why are there 40 channels...? I would like to know.

    I don't think I can answer for the Bluetooth SIG in this case to why its the number 40, but there are some bonuses in using multiple channels. One being frequency hopping, where all BLE devices rapidly change channels in a predetermined pattern. It also allows for multiple devices to communicate. One reason could be that it also just fits nicely when working with the license free band and using things not occupier by WiFi. So the choice of 40 channels in BLE is a likely a practical decision based on spectrum availability, interference avoidance, and system efficiency to some degree.


    Regards,
    Jonathan

Reply
  • +1

    Hi,

    The Radio test sample is used for testing the Radio it is not explicitly made to test BLE. The 80 channels cover the radio span and also covers all 40 BLE channels. Bluetooth data channels are spaced 2MHz apart and are each 2MHz wide and the three advertising channels in the 2.4GHz band with center frequencies at 2402MHz, 2426MHz, and 2480MHz

    In radio test the channel 02 will be 2402MHz, channel 30 is 2430MHz and so forth. 

    Why are there 40 channels...? I would like to know.

    I don't think I can answer for the Bluetooth SIG in this case to why its the number 40, but there are some bonuses in using multiple channels. One being frequency hopping, where all BLE devices rapidly change channels in a predetermined pattern. It also allows for multiple devices to communicate. One reason could be that it also just fits nicely when working with the license free band and using things not occupier by WiFi. So the choice of 40 channels in BLE is a likely a practical decision based on spectrum availability, interference avoidance, and system efficiency to some degree.


    Regards,
    Jonathan

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