Abstract: The invention relates to an inductive plasma torch comprising: a cylindrical metal containment cage (1); a metal element solidly connected to the containment cage (1), extending radially from the periphery of one end thereof; and an inductor (5) surrounding the containment cage (1). The aforementioned containment cage (1) and element are divided along axial planes into regularly distributed sectors, and the sectors are rigidly connected to one another alternately by: a portion of the containment cage (1) on the side opposite the element, or by a portion of the element on the side opposite the containment cage (1).

Abstract: The invention relates to an inductive plasma torch comprising: a cylindrical metal containment cage (1); a metal element solidly connected to the containment cage (1), extending radially from the periphery of one end thereof; and an inductor (5) surrounding the containment cage (1). The aforementioned containment cage (1) and element are divided along axial planes into regularly distributed sectors, and the sectors are rigidly connected to one another alternately by: a portion of the containment cage (1) on the side opposite the element, or by a portion of the element on the side opposite the containment cage (1).

Abstract: Deflection measuring apparatus and methods are used to prevent overstress of printed circuit boards (PCB) prior and during testing. They can be used to verify in a HALT, HASS of ESS testing protocol, if the PCB testing fixture and vibration testing setup would be likely to cause failure of PCB components during pre- testing and testing procedures, which failure would otherwise not occur with faultless components. Furthermore, In the context of a PCB to be integrated to a system as a product such as a computer, the deflection measuring apparatus and methods are used to prevent overstress of PCBs at the system assembly stage, to ensure that operations involved, such as plugging of PCB connectors, will not cause PCB components failure, which would otherwise not occur with faultless components.

Abstract: Methods for determining a vibratory excitation spectrum are tailored to physical characteristics of a structure having critical elements located thereon to be subjected to vibration testing, such as a PCB to which connectors, resistors, capacitors, inductances, Integrated Circuits (IC) or Ball Grid Array components (BGA) are mounted. The physical characteristics includes a frequency response function corresponding to a testing environment temperature and defined in term of power spectral density amplitude over a global excitation frequency range for the vibratory excitation spectrum and characterized by a plurality of power spectral density amplitude peaks corresponding to a plurality of natural resonance frequencies, each being associated with respective mode shape and damping factor.

Abstract: Methods for determining a vibratory excitation spectrum are tailored to physical characteristics of a structure having critical elements located thereon to be subjected to vibration testing, such as a PCB to which connectors, resistors, capacitors, inductances, Integrated Circuits (IC) or Ball Grid Array components (BGA) are mounted. The physical characteristics includes a frequency response function corresponding to a testing environment temperature and defined in term of power spectral density amplitude over a global excitation frequency range for the vibratory excitation spectrum and characterized by a plurality of power spectral density amplitude peaks corresponding to a plurality of natural resonance frequencies, each being associated with respective mode shape and damping factor.

Abstract: A modal analysis method and apparatus for acoustically determining vibration characteristics of a structure uses a MISO model. An acoustic excitation signal toward spatially distributed locations associated with the structure is generated while the latter is held vibrated, one location being chosen as reference. Complementary sets of input acoustic pressure-related signals are produced, one being a reference signal. Fourier analysis is performed on the input signals to provide correlated input acoustic pressure-related data in frequency domain including reference data. Induced output vibration is sensed at a reference point on the structure corresponding to the reference to produce complementary sets of output vibration signals, which are converted through Fourier analysis into sets of output vibration data in frequency domain. Structural transfer functions characterizing each set of input acoustic pressure-related data are obtained from which vibratory characteristics of the structure are derived.

Abstract: A vibration testing system using acoustical waves having a testing unit including a main enclosure defining a main acoustical cavity and having a baffle provided with a main opening which is aligned with a set of acoustical insulation bands receiving an article to be tested that are clamped on a fixture secured to the baffle, so that the main opening is substantially closed by the article and the acoustical insulation bands. The apparatus includes a main acoustical source comprising a main acoustical transducer such as a loudspeaker which is acoustically coupled to the main acoustical cavity, and a subsystem for driving the loudspeaker which generates acoustical waves imparting vibration to the article accordingly. The apparatus preferably also includes a further acoustical source in the form of one or more further loudspeakers facing the main loudspeaker with the baffle extending therebetween, the further loudspeakers showing complementary frequency operating ranges.

Abstract: A modal analysis method and apparatus for acoustically determining dynamic vibration characteristics of a structure, including natural frequencies, mode shapes and damping factors, is based on a Multiple-Input-Single-Output (MISO) model. The method and apparatus involve generation of an acoustic excitation signal toward n spatially distributed locations associated with the structure while the latter is held to allow vibration thereof, one of the locations being chosen as a reference location. A series of microphones are disposed at the locations to produce m complementary sets of n input acoustic pressure-related electrical signals, one of these being chosen as a reference signal associated with the reference location. A Fourier analysis is performed on the sets of input acoustic pressure-related electrical signals to provide corresponding sets of correlated input acoustic pressure-related data in the frequency domain including reference data associated with the reference signal.