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Working of the system if the 863.5MHz is to eb replaced with other bands

stefan 12
Expert 1780 points
Other Parts Discussed in Thread: SIMPLICITI, SMARTRFTM-STUDIO

Hello,

I am now currently using CC1111F32 USB  dongle as the receiver and transmitting the data from the trasnmitter board having same RF circuit as the CC1111F32.The data is being transferred after every 1 second from the transmitter to Receiver (CC1111F32 USB dongle)  and is being didpalyed on the monitor.

I am using TI's- simpliciTI with RF frequency  of 869.524963 MHz , channel spacing of 199.951172 kHz and modulation technique as GFSK.

It is working fine but can someone explain what will(can) be the difference in using the RF frequency from the other two bands of 

433.050 – 434.790 MHz (ETSI EN 300 220)
ƒƒ
2400 – 2483.5 MHz (ETSI EN 300 440 or ETSI EN 300 328)

instead of using RF freuency from the 863.0 – 870.0 MHz (ETSI EN 300 220)v band(currently uisng band)

Thanks.

  • 0
    TI__Mastermind 39860 points

    CC1111 does not support 2.4 GHz operation so it will not work for this frequency band.

    433 MHz operation is possible and the USB dongle will be functional. However, the balun and antenna is tuned for 868/915 MHz operation so you will get degraded output power and sensitiivty (i.e range) when operating at 433 MHz. Furthermore, you will fail EU regulations as the attenuation of harmonics will not be sufficient (e.g. no attenuation of the 2nd harmonic when using a 868 MHz design @433 MHz).   

  • 0 in reply to Sverre
    Expert 1780 points

    Thanks for the clear explanation.

    Can I get ome help with these as well

    1)how to calculate(or know) the output power of the Transmitter if the implemented RF methodology uses  869.524963 MHz and GFSK.

    2)And also can I get some explanation about channel spacing I mean how will it effect the RF communication and factors should be taken into account for calculating the needed channel spacing.

     

  • 0 in reply to stefan 12
    TI__Mastermind 39860 points

    1) RF output power is set in register PA_TABLE.

    From SmartRF Studio:
    +10 dBm: 0xC2
    +7 dBm: 0xCB
    +5 dBm: 0x84
    0 dBm: 0x50

    Refer to CC1110/CC1111 for PA_TABLE settings for other output powers.

    2) For a channelized system the channel spacing should be >= RX filter bandwidth. As an example, if the RX filter BW is configured as 140 kHz the channel spacing should be at least 140 kHz. The larger the spacing, the better as the adjacent channel rejection (i.e selectivity) increases when the adjacent channel is further away (in Hz) 

  • 0 in reply to Sverre
    Expert 1780 points

    Thanks and can you please explain  of  what(or which lines of code in the simpiciTI) sets the RX filter BW. 

  • 0 in reply to stefan 12
    TI__Mastermind 36375 points

    Stefan, 

    Please download our SmartRF Studio V7 software from our website. It is very insightful to what register does what and how to configure it.

    http://www.ti.com/tool/smartrftm-studio

    From it, you can change a configuration and see the register change being highlighted.

    To answer your question : MDMCFG4 

    Regards,
    /TA