FM sensitivity is bad at 103MHz

We design productor with FM funciton,

But FM sensitivity is very bad at 103MHz only, there is 10db worse than other frequency.

I do some analysis and experimentation, but I can't find root cause also.

please give me some suggetions.


(Note, FM is 1.8v and 3.3v power supply and 24MHz clock)

I think you need to give some more information - a circuit for example.

Keith.

Is possible to get receiver desense on that channel from an internal source, which can be the harmonics of a clock signal, or mixing products with other oscillators.
On the net you can find freeware "spurious search" programs, where you can introduce all the clocks and oscillators from your device and find the resulting mixing products, which can fall on 103MHz.