Abstract
The influence of statistical gain fluctuations of the high-frequency amplifier on the sensitivity of a Dicke radiometer with selective videoamplifier is calculated with methods that are used in describing random processes. It is shown that the radiometer sensitivity depends on the power density spectrumS g (f) of the gain fluctuations for a Dicke-radiometer of the zero-balanced as well as the unbalanced type. The sensitivity of the zero-balanced radiometer is dependent onS g (f m ) wheref m is the modulation frequency. That of the strongly unbalanced radiometer depends on the product of the input temperature difference and the integral\(\int\limits_{ - \infty }^{ + \infty } {S_g \left( f \right)df} \). The sensitivity formula for the zero-balanced radiometer can be used to evaluate the power density spectrumS g (f), whereas the sensitivity formula for the unbalanced radiometer can be employed to find the value of the integral\(\int\limits_{ - \infty }^{ + \infty } {S_g \left( f \right)df} \), which governs the integral gain fluctuations.
Zusammenfassung
In dieser Arbeit wird der Einfluss statistischer Verstärkungsschwankungen des Hochfrequenzvertärkers auf die Empfindlichkeit eines Dicke-Radiometers mit selektivem Video-Verstärker berechnet. Das Resultat zeigt, dass die Radiometerempfindlichkeit vom LeistungsspektrumS g (f) der Verstärkungsschwankungen abhängt, beim null-balancierten Radiometer vonS g (f m ), wobeif m die Modulationsfrequenz bedeutet, und beim unbalancierten Radiometer vom Produkt der Differenz der Eingangstemperaturen und dem Integral\(\int\limits_{ - \infty }^{ + \infty } {S_g \left( f \right)df} \). Mit Hilfe der Formeln für die Radiometerempfindlichkeit kann das LeistungsspektrumS g (f) der Verstärkungsschwankungen des Hochfrequenzverstärkers experimentell bestimmt werden.
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Dedicated to Professor K. P. Meyer for his 60th anniversary
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Magun, A., Künzi, K. Influence of statistical gain fluctuations of the high-frequency amplifier on the sensitivity of a Dicke-Radiometer. Journal of Applied Mathematics and Physics (ZAMP) 22, 392–403 (1971). https://doi.org/10.1007/BF01613985
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DOI: https://doi.org/10.1007/BF01613985