Tensile testing of mild steel samples in annealed condition (1023 K/1.5 hr) was carried out at room temperature (298 K) at a nominal strain rate of 6.7 x 10^-5 per second on polished specimens upto 400 grit finish having a gauge dimension of 50 X 20 X 3 mm. AE monitoring was carried out using both 175 kHz resonant sensor and 100 kHz - 2.1 MHz broadband sensor by placing them directly on the shoulder of the specimen. The AE signal output of the resonant sensor has been subjected to the time domain analysis whereas, the signal output from broadband sensor was used for carrying out the frequency analysis. The gain and threshold value for time domain analysis were selected such that no external noise was picked up. Threshold setting for broadband transducer does not play any role for frequency analysis of the AE signal since post amplified AE signal was recorded and analysed.

AE signals generated during Luder's and uniform deformation regions have been compared using rms voltage, b-parameter for the events generated and frequency spectra. It has been observed that AE captured during Luder's deformation is of strong and burst type whereas, AE generated during uniform deformation region is weak and of continuous type. Nucleation of Luder's band as a result of dislocation unpinning in undeformed slip systems is responsible for large and burst type AE. During uniform deformation region, the rate and amplitude of pulses are low owing to the absence of high energy dislocation processes. Luder's band nucleation and uniform plastic deformation region show characteristic frequency spectra.