（CL=9PF的无源晶振27MHz，外接电容C1=C2=10PF）

晶体（无源晶振）CL和PCBA（电路板） CL的关系解释如下：

We produce the crystal CL to satisfy the customer’s request. Nominal frequency means that the crystal CL and the PCBA CL meet (no frequency deviation) each other in the oscillator circuit in order to satisfy with the customers.

我们制造出晶体负载电容CL以满足客户要求。标称频率（Nominal Frequency）是指在振荡器电路中，PCBA CL需要与晶体CL完全匹配（产生无偏差频率），以满足客户需求。

If the CL of PCBA is higher than the crystal, the output frequency should lower than the nominal frequency.

如果PCBA的CL高于晶体，则输出频率应低于标称频率。

If the CL of PCBA is lower than the crystal, the output frequency should higher than the nominal frequency.

如果PCBA的CL低于晶体，则输出频率应高于标称频率。