Spectrum analysis uses Fourier analysis for detecting the spectrum of a signal. The signals to be analyzed must be stationary that their spectra must not varying with time. For signals whose spectra varying with time (non-stationary) such as seismic signal, biomedical signal, speech signal, Joint Time-Frequency Analysis (JTFA) must be used. The work is to design PC- based Joint Time- Frequency Analyzer including the methods that used to calculate and display energy in Time-Frequency domain. These methods are the Short time Fourier transforms (STFT), Wavelet Analysis (WT), and Wigner-Ville distribution (WVD). Using the Graphical User Interface (GUI) for the Matlab software, front panel is designed as control panel involving all functions and tools necessary for the analysis.
Hardware requirements for interfacing the signal to the PC are considered and designed. The sound card used for signals in the audio range. External signals can be recorded, displayed, measured, stored and processed in time-domain, frequency-domain, and time-frequency domain.
Keywords: Digital signal processing, JTFA, Time-Frequency Analyzer