Posts: 20
Registered: ‎07-01-2013

Si4731 frequency shift

[ Edited ]


I have selfmade board based on Si4731-D60 and C8051F320.

Board is used for FM audio recording in 24/7 mode.

After about one month of continuous operation the signal noise is noticably increased.


If I send comand to tune frequency again sound quality becomes perfect.


It seems that tuned frequency is slowly shifts!?


1. How can I read current frequency from Si4731?

Can I use fmRsqStatus() and FREQOFF value to control frequency shift?


2. What do I have to check on my board to ensure stable frequency?







Posts: 53
Registered: ‎01-27-2015

Re: Si4731 frequency shift

Hi Roman,

Are you using the battery or the DC power supply?

From my understanding, the tuned frequency will shift only if the RCLK shifts, or the temperature changes a lot.

Next time when this issue happens, you can check the accuracy of the RCLK.

1. Yes, you can use the CMD Command 0x23. FM_RSQ_STATUS to monitor the frequency offset.
2. Not sure what causes this issue at this stage. But you can ensure the stability of the RCLK. And if the temperature changes a lot (if you can get real-time temperature) , do a new tune.

Posts: 20
Registered: ‎07-01-2013

Re: Si4731 frequency shift

I use DC power supply.

Thank you for recommendations.