Method for Measuring Unwanted Out-of-Band Emissions

Accordingly, the method of measuring unwanted out-of-band emissions is regulated by Circular 29 as follows:

- For IE, the EUT must be placed between the IME and EME and at a distance of 0.5 m, connecting the cable with the maximum length as specified by the manufacturer. The cable height should be between 0.5 m and 1 m. The cable is held at that position by a non-metallic device. In the nominal operating configuration, the EME is placed on a non-metallic table at a height of 0.5 to 1 m. The IME is placed on a non-metallic table at a height of 0.8 m for measurements at frequencies up to 1,000 MHz and from 0.5 m to 1 m for measurements at frequencies above 1,000 MHz. Any accessories related to the equipment, such as laptops or data terminals, if necessary for the operation of the MES, must be placed next to and at the same height as the IME.- For PE, the equipment is configured for normal operation according to the manufacturer's recommendation and placed on a non-metallic table at a height of 0.5 m to 1 m.- The EUT must be connected to appropriate impedances at the ground ports if no suitable equipment is connected to those ports as required by the manufacturer in the user manual.- For frequencies up to 80 MHz, the measuring antenna must be a balanced dipole with a resonant length at 80 MHz and should adapt to the feeder with a suitable converter device. Measurements with a broadband antenna can be performed if the measurement location is standardized in accordance with the requirements of CISPR 16-1.- For frequencies between 80 MHz and 1,000 MHz, the measuring antenna must be a resonant-length balanced dipole antenna. Measurements with a broadband antenna can be performed if the measurement location is standardized in accordance with the requirements of CISPR 16-1.- For frequencies above 1,000 MHz, the measuring antenna is a horn antenna with known gain/frequency characteristics. When used for reception, the antenna and associated amplification system must have amplitude/frequency response within ± 2 dB of the standard curves over the frequency range of interest for the antenna.

See details in Circular 29/2017/TT-BTTTT effective from July 1, 2018.

-Thao Uyen-

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