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Acoustic spectra for radio signal DAB and FM

18 marca 2017 Dodaj komentarz

Measurement of Spectra a signal using a Fast Fourier Transform FFT in the domain of time are performed in a finite time. In other words, the measured are portions of a waveform of the signal of the specified length. Fragments extracted cyclically subjected are to the FFT. Fragments the waveform on shores contains discontinuities because are collected at intervals. Discontinuities cause blurring to spectra. The spectra of the downloaded portions of the waveform are different from the spectra of the whole continuous the signal subjected to measurement. To reduce blur spectra signal is passed the signal through a time window. The Time window reduced spillage of energy in the domain of frequency. Measurements were made for spectra of acoustic signals DAB and FM. The signal was passed through a time window. Used were of the time window: Rectangular, Bartlett, Hanning, Hamming, Blackman, Blackman-Harris, Flat-Top. The time window it is function shaping the signal measured undergone FFT. In the domain of time, signal is as function of time and was multiplying with function describing by the time window. In the domain of frequency occurs weave these functions. The result of the signal is subjected to FFT.


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Acoustic spectra DAB and FM


radio JT-208

12 października 2010 Dodaj komentarz

moje radio JT-208 przy próbie nadawania przeładowuje się. Nie mam schematu może ktoś ma ?
Po dłuższej chwili ładowania akumulatora generuje moc do anteny ale nic nie słychać na innym odbiorniku. Tak jakby modulator nie działał ?

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