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Dostum diğer forum eklenti kabul etmediği için buraya attım.kolay gelsin...

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Overview & Design Rationale


Spectrum analyzers are used to output the frequency content of an arbitrary input signal. It was our opinion that such a system could be implemented on a microcontroller, almost fully in software. Doing this, however, necessitated some knowledge of standard Digital Signal Processing techniques, namely sampling, analog-to-digital conversion and most importantly constructing digital filters. We believed that a spectrum analyzer could be fully described by providing and/or implementing three main components: sampling & A/D conversion, filtering and output.
Hardware was essential to our project. The ATMEL AT90S8535 provided a sampling and Analog-to-Digital module which greatly facilated the capturing of analog signal for subsequent processing. Of course, using this particular microcontroller put constraints on the capacity and capability of our spectrum analyzer. Due to these constraints, we had to design the analyzer within the appropriate limits. The main constraints imposed by the microcontroller were the maximum sampling frequency (of approximately 9 kHz), RAM and Program Memory. All three factors contributed to limiting the bandwidth, performance and resolution of the analyzer.
In essence, we believed that a spectrum analyzer could be realized through chaining a series of bandpass filters, through which an input signal would traverse during the filtering process. Hence, the major portion of this project involved coding up and testing the various filters that later become the 'frequency points of interest' of our analyzer

http://rapidshare.com/files/70773086/Ye...elgesi.rar

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