The disturbance power of the electrical test compatibility test
The disturbance power is the electromagnetic disturbance power measured under the specified conditions.
It is generally believed that audio power amplifiers, audio / video discs, tape recorders and other equipment, they are more than 30MHz radiation transmission is connected with its power lines and other connecting lines outward radiation. So you can use the power line and other connections on the harassment power to define its radiation harassment performance.
The rigorous measurement procedures and their scope of application are set forth in some of the relevant EMC standards.
Absorbent clamp method: generally applicable to small EUT and 30 ~ 300MHz frequency range of harassment power test.
30 to 300MHz frequency range, the device can be connected with its shielded or unshielded wire radiation to radiate energy. Absorbents are used to test these harassment energies, ie, harassment power.
The frequency is in the frequency range of 300MHz to 1000MHz and can also be measured with a suitable absorber. These measurements also apply to diagnostic tests. It should be noted that the device may produce radiation at this time.
First, the test equipment and requirements
Measurement receiver: 30 ~ 300MHz frequency range with peak, quasi-peak and average detection, to meet the relevant requirements of CISPR16-1-1.
Absorbent forceps: performance should meet the following requirements:
1. The absorber has an impedance of 100 to 200 Ω and a reactance component of less than 20% for the device under test.
2. Absorbent clamp output impedance of 50Ω;
3. Frequency range of 30 ~ 300MHz;
4. Insertion loss 17dB;
5. Absorbent clamps provide sufficient attenuation for harassment from the grid;
6. When the working current of the device under test passes, the magnetic circuit of the absorption clamp should not be saturated.
Second, the measurement method
When measuring with an absorbance pliers, the EUT should be placed on a non-metallic table of the specified height.
The wires to be tested are placed in a straight line in the horizontal direction so that the absorber can move the position along the wire to find the maximum indication value.
For lengths of variable wire, the wire shall be at least half the wavelength of the minimum measurement frequency plus the length of the absorption clamp and the length of the second absorption clamp that may be required: the wire length is 6 m at 30 MHz and the second ( For the filter), it must be at least 7 m.
If the length of the measured conductor itself is less than the specified length, then use the homogeneous wire extended to the specified length. A wire shorter than 1 m is not suitable for use with an absorbance clamp. (Some of the standard requirements for the length of ≥ 25cm to test the wire, then you can switch to the length of more than 1m cable).
