Engineering and R&D

1. Engineering services

     Excem provides a wide range of engineering and R&D services in radio design, EMC, signal integrity, and analog electronics design. We offer expert technical assistance related to radio and EMC standards and regulations.

     We accomplish various tasks ranging from one-day consultancy for EMC or electronic design problem solving, to the apparatus system development project lasting several years. More precisely, the activities expected by our customers may include:

• performing research and development activities, taking into account intellectual property issues.
• writing documentation and reports, sometimes including the specification itself;
• designing electronic assembly, apparatus and systems;
• designing electronic circuits, using CAE tools, circuit synthesis tools for analog and digital filters, circuit simulation software (SPICE), proprietary design tools for EMC problems (Filtrexpert, SpiceLine...);
• designing instrumentation or automation control programs running on PCs;
• creating software for simulation or special computation;
• manufacturing prototypes of electronic hardware;
• performing measurements, calibration and automatic tests in our laboratory;
• compliance to standards and regulations for the European market;
• installing equipments, with or without in situ tests and measurements;
• maintaining and upgrading our products, or the products of other manufacturers;
• providing training seminars in our field of technical excellence, or related to our products;

Fig. 1 : the PCB of a pre-series of loudspeaker controller NX242 (year 2003).

     The above picture shows a loudspeaker controller NX242 of the company Nexo. Nexo has provided the specification, the programs for the CPLD and for the DSP (a Motorola DSP56303 chip), and has taken care of the qualification. Excem delivered the schematic diagrams (a patent on the analog input circuits was applied for), the design and a prototype of the power transformer, the manufacturing files for the PCB, the host processor program (a 80C32 microcontroller), the tools for programming the NX242 using a PC, EMC tests, and the documentation. We have been very attentive to EMC and integrity of audio signals. With the 24 bit ADC and DAC implemented in this design, the audio dynamic range obtained in the band 20 Hz to 20 kHz is close to 111 dB (unweighted) for the analog and digital circuits (analog input to analog output).

     We have gathered a lot of experience in several important areas:

• PCB and equipment design aiming at EMC compliance with the first prototype;
• design of measuring instruments for measurements;
• design of radio-frequency and wide-band equipments;
• design of analog circuits (low-power circuits, low-noise circuits,...);
• design of audio equipments;
• power electronics (up to 5 kW per apparatus, and 6 kV at the output);
• EMC: reduction of unwanted emission, improvement of immunity, control of interferences and noise, protection against ESD, protection against lightning and EMP, standardization, prediction of unwanted couplings, site surveys, design of architectural and equipment shielding, design of set-ups for special measurements for EMC,...
• signal integrity;
• electromagnetisms and antenna design (near-field signal transmission, wireless power transmission, energy harvesting, limitation of human exposure,...);
• simulation of electronic circuits;
• simulation applied to EMC and the propagation on multiconductor transmission lines;
• signal processing (analog and digital);
• complex electromagnetic calculations;

Fig. 2: EMC measurements in an anechoic room

     The deliverables of Excem may include a prototype and/or software and/or a measurement or calculation report. Sometimes we only deliver the definition of a technical solution. The output is always delivered according to our quality assurance system. Please also note that we understand all aspects of intellectual property: patent applications, protections of drawings, copyrights on software and documents. Of course, we are very careful to keep the secrets of our customers.

Fig. 3: Excem's engineers working on an array of log-spiral antennas for decametric waves

2. Research and development

     Excem is also known for its research activities. Reasearch may be the result of a research contract with a customer, or internally financed. Some of our research work has been published. When the research result belongs to us, we sometimes apply for patents ourselves.

     A first example is our research activity concerning the improvement of the performances of interconnections, related to several patent applications. These innovations are presented elsewhere on this site.

     A second example is the development of the L2G series of fault location systems between 1993 and 1997 (these equipments are no longer available for sale). This research work was not published, if one does not take into account the patent we have applied for. This research work included:

• the investigation and modelization of electrochemical phenomena at the cable/sea water interface (with the help of laboratory measurements),
• the creation and validation of new fault location algorithms,
• the exact assessment of fault location accuracy as a function of all relevant parameters.

     A third example is the invention of an innovative system for continuous monitoring of shielded room integrity (references B14, B16, B19, B26). Several patents were applied for on this project. The first batch of four protopypes shown on the picture was intended for validation of the invention on real Faraday cages.

Fig. 4: A small series of four prototypes of a shielding monitoring system (year 1990)

     A fourth example is a system for the characterization of inhomogenous electromagnetic absorbing materials (reference B17). We designed and built the appropriate instruments and software. We thereafter used them to characterize these absorbers.

Fig. 5: Characterization of electromagnetic absorbers (year 1991)

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