Problems and phenomena: the quartz resonator circuit assembly, the value of the frequency is not required, resulting circuit can not work properly.
    Analysis: This multi-resonator with spurious vibration related, and sometimes unreasonable and circuit design related. As mentioned earlier, there are multiple quartz experience spurious response of thickness shear crystal for frequency above 20MHZ, especially overtone crystal easy to produce spurious responses. Base overtone crystal frequency resonance resistance sometimes with three overtone resonance resistance difference is small, the filter circuit without oscillation when possible on the fundamental frequency, and therefore should be combined with the selected frequency in the circuit design to avoid this from happening Loop .
    Another reason is that the harmonic wave of the fundamental frequency of the crystal 3 octave (3rd harmonic) frequency of the third harmonics are very close to the frequency selection circuit is difficult to filter out, resulting in the hopping phenomenon.
    If this happens there may be, at the time of ordering, you should make fundamental frequency 3 octave frequency overtones and spacing requirements three times, usually in 150-250ppm room. It may be appropriate to reduce the gain of the circuit in the design of the circuit, reducing the third harmonic components.