化二,你看下这两个电路是不是有一个不对啊,图一 PE线端也接地了,那就是L线和N线也直接接地了,那L线和N线接的150欧姆电阻是不已经没有作用了呢?电感对频率高的信号有较大的阻抗,[im
g][/img]在 IEC61000-4-6里面有这么一段文字:6.2 Coupling and decoupling devices
Coupling and decoupling devices shall be used for appropriate coupling of the disturbing signal
(over the entire frequency range, with a defined common-mode impedance at the EUT port) to
the various cables connected to the EUT and for preventing applied test signals from affecting
other devices, equipment and systems that are not under test.
The coupling and decoupling devices can be combined into one box (a coupling/ decoupling
network, CDN) or can consist of several parts. The main coupling and decoupling device
parameter, the common-mode impedance seen at the EUT-port, is specified in Table 3.
Table 3 – Main parameter of the combination of the coupling and decoupling device
Frequency band
Parameter 0,15 MHz – 26 MHz 26 MHz – 80 MHz
| Zce| 150 Ω ± 20 Ω 150 Ω + 60 Ω – 45 Ω
TE 1 Neither the argument of Zce nor the decoupling factor between the EUT port and the AE port are specified
parately. These factors are embodied in the requirement that the tolerance of |Zce| shall be met with the AE-port
en or short-circuited to the ground reference plane. 所以 我觉得 那个电感值在150KHZ时 取值为L ≥ 280 μH与以上所叙述的所谓阻抗要求有关。但根据电路,我不知道这个值是如何算出来的。 |