Abstract: The subject method pertains to a method and apparatus for welding. The subject invention can be utilized for welding very thin sections of stainless steel. The subject technique can incorporate a laser, such as a Nd:YAG, CO2, or diode laser. Furthermore, the laser may be a continuous wave (CW) or pulsed type. The subject invention can reduce or eliminate the need for expensive seam tracking or line following devices to compensate for tooling tolerances, stamping tolerances, and other effects leading to movement of the parts as they are rotated under a welding means. The subject invention can enable high quality symmetrical welds on thin sections of material, while reducing the attention required by a human operator. Furthermore, the method can be applied to other materials. Because of the nature of the beam delivery system, the spatial mode structure of the laser beam is no longer critical to the weld quality of the finished product.

Abstract: An active noise cancellation apparatus and method for actively reducing the level of noise generated by an ambient noise source, such as a domestic appliance. This active noise cancellation apparatus has a pickup device (1, 20) to translate the noise into an electrical signal, a buffer amplifier (2, 22) to allow the distribution of those signals to a digital filter section (3) having a series of switched capacitor filters for analyzing and dividing the signal into separate harmonic signals, a dual analog delay line (4) for producing a phase shift in the signals, a summing amplifier (2,6) to recombine the signals into one signal, a power amplifier (5, 27) to drive an output loudspeaker (6, 31) which produces a phase shifted sound wave to cancel the noise generated by the ambient noise source.