Fundamental Study on the Influence of SSC to Digital Television Reception

Spread Spectrum Clocking (SSC) is used for many PCs to satisfy a regulation of emission. The SSC affects to the wideband radio communication system, such as wireless LANs, compared with the narrow band radio communication system because SSC has a wide band spectrum. In this paper, the influence of SSC to the digital TV signal was compared with the influence to the analogue TV signal. A frequency modulation (FM) signal was used instead of the SSC signal. And these signals were impressed to both the analogue and the digital TV signal simultaneously. The received image quality was evaluated by the mean opinion score (MOS). The ratio of the disturbance to the broadcast signal level (DU ratio) was used as the parameter. The quasi peak level was used to calculate the DU ratio. The results indicated that the difference of DU ratio, when FM and AM signal were impressed to the TV signals, was small in the case of analogue TV, but the deviation of DU ratio is about 15 dB in the case of a digital TV. The results also show that the DU ratio of the digital TV was 20 dB lower than that of the analogue TV when MOS was 3.2009 International Symposium on Electromagnetic Compatibility (EMC\u2709/Kyoto), July 20-24, 2009, Kyoto International Conference Center, Kyoto, Japa

Probe for measuring interference voltages at ISDN telecommunication line interfaces

Information technology equipment connected to ISDN (Integrated Service Digital Network) telecommunication lines can be a source of emission noise. A probe for measuring interference voltage s at ISDN telecommunication line interfaces is designed to satisfy the ISDN system operation conditions. The asymmetrical characteristic impedance of the probe is designed to measure the voltages appearing at the interfaces of the telecommunication lines. The measurement error due to longitudinal conversion loss of the telecommunication lines is also studied. Investigation shows that the normal mode interference voltages should be measured to estimate the common mode voltages, which are converted from normal mode voltages by unbalance of telecommunication lines.1988 International Symposium on Electromagnetic Compatibility, August 2-4, 1988, Seattle, WA, US

Calculation of Near Field Emitting from Telecommunication Lines

An analytic expression of electromagnetic near field emitted by a single current flow along a straight wire is derived to obtain the radiated EMI limit from the telecommunication lines connected to the equipment. The validity of the theory is tested in the experiment. Calculations show that the conversion factor between the electric field strength and the terminal voltage is not significantly changed by the wire length. A maximum conversion factor of about - 30 dB in the frequency range of 0.1- 30 MHz is obtained

Frequency Response Improvement of Electric Field Sensor using Optical Modulator

This paper describes a method of improving the frequency response of an electric field sensor. A modified LiNbO/sub 3/ substrate shape reduces the sensitivity deviation from 4 [dB] to 1 [dB] and the maximum operating frequency is raised from 300 [MHz] to 1 [GHz] by using a resistive loaded element.1994 IEEE Instrumentation and Measurement Technology Conference, May 10-12, 1994, Grand Hotel Hamamatsu, Hamamatsu, Japa

Recent Progress in Fiber Optic Antennas for EMC Measurement

Recent progress in electromagnetic compatibility (EMC) technology has created a need for small and wideband antennas that can be used to measure the quality of EMC measurement facilities and to measure electric field strength for immunity tests and human hazard studies. Antennas using fiber optics are being developed because this kind of antenna has the wideband property and can eliminate the influence of the coaxial cable. This paper first summarizes the development of fiber optic antennas for EMC measurement and the construction of practical fiber optic antennas. It then describes the recent progress that has been made in Japan. This progress includes the electromagnetic source and the electric field sensor using a spherical dipole antenna with O/E or E/O converters, and it includes a wideband electric field sensor using electro-optical crystals

Optical-Bias-Controlled and Temperature-Stabilized Electric Field Sensor Using Mach-Zehnder Interferometer

This paper describes an electric field sensor which can control optical bias angle and improve the temperature drift of the sensitivity. The optical bias angle is controlled by applying a suitable stress to the LiNb0 3 substrate, and the temperature drift is reduced by inserting a Si semiconductor layer between the electrode and the Si02 buffer layer. The optical bias angle can be changed from 40[deg.] to 90[deg.], and temperature drift of the insertoin loss is within 2[dB] over a temperature range from O[deg.] to 40[deg.].1994 International Symposium on Electromagnetic Compatibility (EMC\u2794/Sendai), May 16 - 20, 1994, Hotel Sendai Plaza, Miyagi, Japa

Impedance stabilization network for measuring disturbance at balanced multiple-pair telecommunication signal ports

A design method of Impedance Stabilization Networks (ISNs) for measuring disturbances at balanced multiple-pair telecommunications signal ports is proposed. This paper describes that newly developed ISN designed by the proposed method meets the draft requirements proposed by IEC/CISPR Sub-Committee G and can measure disturbances at telecommunication signal ports of both analog and digital telecommunications equipment without a current probe.1994 International Symposium on Electromagnetic Compatibility (EMC\u2794/Sendai), May 16 - 20, 1994, Hotel Sendai Plaza, Miyagi, Japa

Theoretical Analysis of a Ridged-Waveguide Mounting Structure

The driving-point impedance of a single-gap thin conductor strip, a model of the ribbon-and-pedestal of diode package, mounted across the gap of a ridged waveguide has been derived using the induced EMF method. The dyadic Green\u27s function for the ridged waveguide is derived to facilitate the analysis. An equivalent circuit is developed which involves an infinite array of transformers representing the couplings between the conductor strip and the waveguide normal modes. Numerical results for a typical example are presented to discuss the validity of the analytical results and also to demonstrate a remarkably smooth behavior of the driving-point impedance of the mount over a frequency range from 5.4 to 25.4 GHz

Radiation properties of a spherical dipole antenna

This paper describes an advanced spherical dipole antenna for use as a standard electromagnetic field emission source. Its radiated field is easily calculated, and its radiated frequency and amplitude are controlled over a wide frequency range by an outside signal generator through an optical fiber. The radiated field is calculated by the mode-matching method, and also measured for comparison. The theoretical and experimental values differ by less than 1dB in the frequency range 30 MHz-1000 MHz.International Symposium on Antennas and Propagation (ISAP1989), August 22-25, 1989, Tokyo, Japa

Electric field strength specification method under 80 cm for RF immunity testing

Electric field distribution below 80 cm should be specified to test the RF immunity of the floor-standing equipment. To determine this specification, a model in which the equipment is set on an infinite ground plane was used. Calculations using the moment method show that the height pattern of the field below 80 cm is independent of frequency. The height pattern measured in a room is close to the calculated pattern in this model. Experiments show that a suitable electric field can be almost generated by arranging RF absorbers on the floor of a semi-anechoic chamber.1993 International Symposium on Electromagnetic Compatibility, 9-13 August, 1993, Dallas, TX, US