Abstract:
Developinents of spectrum analyzer for field instruments are described in the thesis. The designs area digital signal processing circuit interfaced and worked together with a handheld computer likeTM Palm as a handheld instrument. It can be applied to analyze noise and vibration with 113-octavemethod. Frequency range is from 25 to 20,000 I-Iz or 30 frequency band. Multirate DSP technique isused to reduce the calculation needed in real time analysis in order to reduce sampling rate of eachoctave in half and. to arrange the processing time diagrams. All of digital filters are designed underIEC 61260 criterion. The IEC 61260, electro acoustic octave-band and fractional-octave-band filtersstandard, classifies the error boundary and the attenuation boundary for each frequency band asclass 0, 1 and 2. According to the performance the prototype has 0.3 decibels of error at midbandfrequency and level attenuation is in standard class 1. Furthermore, 1024-point FFT and the timedomain signal waveform and level can be computed and displayed using this prototype.