Hi,
Is there root cosine filter in 4FSK mode of CC1125?
We have found that the sideband rejection was not good.
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Hi,
Is there root cosine filter in 4FSK mode of CC1125?
We have found that the sideband rejection was not good.
Hi,TA12012
Thanks for your reply.
We are using CC1125 to design a new radio modem, but our old product has used a baseband IC to acomplish encoding and decoding. And the baseband IC has root raised cosine filter in both transmit and receive modes.
We have compared the spectrum with modulation, and found that the sideband rejection is different seen as following pictures.
Spectrum of baseband IC:
Spectrum of CC112X:
And we found that the receiver perfomance was not good when communicated with old product which used baseband IC.
Transmitter Receiver Result
CC1125 Old product OK
CC1125 CC1125 OK
Old product CC1125 No good, there was error bits
The BT is fixed.
Since the chip does not support root cosine directly you can look into the "Custom Frequency Modulation" feature (section 5.2.4 in the UserGuide) and use the raw data to code/ decode.