ad698 select Oscillator Frequency by Analog Switch

hi :

  we are designing a universal LVDT signal conditioner using AD698 for different Frequency LVDT,  to control the ad698 oscillator frequency by analog switch ADG1411. the problem is we can not get the exc wave at PIN 2 AND PIN 3. when we move ADG1411 the wave is normal ok,  we checked the adg1411 has 170MHz bandwidth, what is the problem?