A sensor stem supporting a sensor element comprising a metal plate having a shape defined by press, the metal plate include a dent portion formed on a first surface of the metal plate, a step portion formed on a second surface of the metal plate facing the first surface, and a projection formed on the step portion for resistance welding. Type of surface properties that are altered by the disclosed methods include by electrostatic properties, hydrophobic properties and hydrogen bonding properties. In one embodiment, the autocorrelation coefficients may be used to predict the original audio signal to be subtracted from the original audio signals and to generate residual signals A Bluetooth transceiver is configured for transmitting the set of coefficients andor residual signals as data to another device, which utilizes the coefficients for speech applications. The system also provides signal parameter measurements while requiring less power, size, and weight than conventional systems. The polishing tape of the present invention can noticeably improve the surface roughness of the polished substrate.