CC1120 FHSS FCC question

Miha Korosec

Other Parts Discussed in Thread: CC1120

Hi,

I'm working on FHSS with CC1120 for FCC P15.247 cerfitication.
There is a lack of understanding with directive (a) (1): "Each frequency must be used equally on the average by each transmitter."

Let say that I use 50 hopping channels. On each channel I send 8 byte data packet. But on one channel I want to send 4 byte data packet twice during complete hopping sequence.

Is It still within the limits of the directive if in one hopping sequence transmit data packet in each of the 49 channels and 2x on hooping channel with twice less data?

Thanks for answers or suggestions.
Miha

over 7 years ago

0 Sverre over 7 years ago

TI__Mastermind 39860 points

Your implementation as you describe it will be perfectly fine.

0 TA12012 over 7 years ago

TI__Mastermind 36375 points

Miha,

Please note that we are not allowed to interpret the rules for you, this is a matter for the regulatory test houses. So please find a certification house and ask them the same question.

To answer your question you will also need to know what the repetition rate is of your system. There is a requirement that each channel shall be used equally over a 20 second measurement window. Therefore the repetition rate is also very important.

Regards,
/TA

0 Miha Korosec over 7 years ago in reply to TA12012

Prodigy 20 points

Thanks for all suggestions.

Data package is small (couple ob bytes). My repetition rate is not defined jet, but I assume that I will send data package with hopping channel change every second. So FH cycle will be repeat every 50 seconds.

TA12012 said:
There is a requirement that each channel shall be used equally over a 20 second measurement window.

Do you have any reference to this statement?

Best regards,
Miha

0 PM over 7 years ago in reply to Miha Korosec

TI__Mastermind 27145 points

Hi,

TA12012 means the following.

Thanks,

0 PM over 7 years ago in reply to PM

TI__Mastermind 27145 points

HI,

I observed the ScreenShot is missing in the above post.

Attached is SS from 15.247.

TA12012 means the following

Thanks,

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CC1120 FHSS FCC question