| Title |
Characteristics of Multimedia Transmission Signals and Radiated EMI with Connecting HDMI Cable |
| Authors |
최병인(Byeong-In Choi) ; 좌성훈(Sung-Hoon Choa) |
| DOI |
https://doi.org/10.5573/ieie.2021.58.7.3 |
| Keywords |
HDMI; Electromagnetic interference; Multimedia transmission signals |
| Abstract |
Recently, the increase in data transmission speed using Ethernet technology has enabled various Ethernet-based multimedia services. A set-top box is commonly used for multimedia service devices, and set-top box transmits multimedia signals to TV according to the HDMI(high definition multimedia interface) standard. The signal from set-top box must be transmitted normally to TV and monitors, and qualified certifications of HDMI and radiated electromagnetic interference(EMI) are essential to guarantee the performances of transmission signal and EMI. It was assumed that there will be no problems in performances of transmission signal and EMI when the certified HDMI cable is connected to set-top box and TV. In this study, we investigated the possibility of degradation in transmission signal and EMI characteristics when the HDMI cable is connected to set-top box and also connected to TV. In the experiment, HDMI and EMI-certified HDMI cable, set-top box, and TVs were used respectively. First, when the HDMI cable was connected to set-top box, the rise and fall times of the transmitted signals met the HDMI compliance test specification(CTS), but the mask waveform did not meet the HDMI CTS standard. Secondly, set-top box was connected to two different types of TVs using HDMI cables, one type of TV did not meet the radiated EMI standard, and the distributions of radiated EMI noise were different according to types of TVs. The connection of the HDMI cable to set-top box and TVs might cause the degradation in the performance of signal transmission and EMI, and consequently did not meet the certification standards. Therefore, the signal and EMI performances should be tested with TV, set-top box, and HDMI cable connected before shipping, and their results must be notified. |