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ADF7020 - demodulation on adjacent in 433Band

Question asked by invivus on Feb 3, 2015
Latest reply on Feb 3, 2015 by rbrennan

Hello,

 

We have done some product based on ADF7020 on 860MHz Band and we have any difficulties with those.

 

With the same hardware (except matching and this kind of thing) we have done a 433MHz band product. With this one with a modulatuion FSK 14.1kHz of deviation and baudrate of 10kbit/s (same as 860MHz band) we are able to demodulate on the two adjacent channel, not on the third and also possible on the four. Exemple with number of channel (each one separated of 100kHz) ( exemple first line : tx on channel 10, rx on channel 6 so 400kHz adjacent and reception is OK...):

 

 

txrx

10

6

OK

6

10

KO

10

7

KO

7

10

KO

8

10

OK

10

8

OK

10

10

OK

9

10

OK



10

14

KO

14

10

OK

10

13

KO

13

10

KO

10

12

OK

12

10

KO

10

11

OK

11

10

OK

 

We have check register but it's seems to be OK... IF bandwith is set to 100kHz... AFC is on in all case. The modulation is the good one frequency too...

 

Why we have this problem in 433MHz band and not on 860MHz Band ?

 

The IF frequency is 200kHz or 400kHz ? because page 6 and 26 of datasheet it say 400kHz and on figure 9 it's indicated 200kHz as on figure 35 ...)

 

Thanks in advance for your help...

 

Best regards, Fabien

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