1/f noise: a pedagogical review
نویسنده
چکیده
The triode was invented by Lee de Forest in 1907, and soon afterwards the first amplifiers were built. By 1921 the "thermionic tube" amplifiers were so developed that C. A. Hartmann [1] made the first courageous experiment to verify Schottky's formula for the shot noise spectral density [2]. Hartmann's attempt failed, and it was finally J. B. Johnson who successfully measured the predicted white noise spectrum [3]. However Johnson also measured an unexpected "flicker noise" at low frequency: his results are shown in figure 1, and shortly thereafter W. Schottky tried to provide a theoretical explanation [4].
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