CC1120EM-868-915-RD: What is the register configuration for long range mode running at 915MHz?

Joseph LIANG

Intellectual 300 points

Part Number: CC1120EM-868-915-RD
Other Parts Discussed in Thread: CC1120

Hi!

What is the register configuration for long range mode running at 915MHz?

I want to test the max range of CC1120em in the US.

Thanks.

Joseph

over 7 years ago

0 TA12012 over 7 years ago

TI__Mastermind 36375 points

Joseph,

We have created this appnote to show long range on CC1120, it also contains a frequency hopping algorithm so that your solution remains FCC compliant.

www.ti.com/.../swra482.pdf

Software is linked in the application note.

Regards,
/TA

0 Joseph LIANG over 7 years ago in reply to TA12012

Intellectual 300 points

TA,

I browse the program but I found the frequency for the long range mode is 470MHz and 868MHz. However in US these two are not appliable. Do you have configurations for 915MHz band?
Thanks.

Best,
Joseph

0 TER over 7 years ago in reply to Joseph LIANG

TI__Guru**** 317180 points

Note that we don't have a defined long range mode for CC1120. You will get longer range if you increase the output power or increase the sensitivity. The later you can do by lowering the datarate and lowering the Rx Bw.

In SmartRF Studio you will find a couple of settings with low datarate that will give good sensitivity. These can also be used on 915 MHz by setting the frequency to 915 MHz.

Required RX filter bandwidth can be approximated as: Signal BW + 4*ppm xtal*Frequency of operation , where Signal BW of = Data rate + 2 x frequency deviation.

Example: 38.4 kbps data rate and +/-19.2 kHz deviation gives Signal BW of38.4 + 2 x 19.2 = 76.8 kHz

To use low Rx Bw would therefore require a TCXO.

0 Joseph LIANG over 7 years ago in reply to TER

Intellectual 300 points

Thanks very much TER! The answer is very complete so I know what to do next.

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CC1120EM-868-915-RD: What is the register configuration for long range mode running at 915MHz?