An astronomer researching exoplanets.^[ref]

An astronomer researching exoplanets.^[ref]

An astronomer studying the Milky Way centre.^[ref]

An astronomer studying the Milky Way centre.^[ref]

An astronomer studying the Milky Way centre.^[ref]

An astronomer researching exoplanets.^[ref]

An astronomer researching radio astronomy.^[ref]

An astronomer who designed astronomical spectrographs, including ELODIE.^[ref]

An astronomer.^[ref]

An astronomer.^[ref]

A chosen boundary in a frequency response, commonly where the voltage amplitude gain falls to $1/\sqrt{2}$ of its pass-region value. The convention must specify the reference gain.

For a linear time-invariant system, a sinusoidal wanted signal at ${\omega }_s$ and an unwanted sinusoidal component at ${\omega }_n$ acquire their separate frequency response factors. The ratio of their output amplitudes, divided by their input amplitude ratio, is $\eta =|H({\omega }_n)|/|H({\omega }_s)|$. An amplitude attenuation factor of $F=1/\eta$ corresponds to a factor $F^2$ in squared-amplitude power ratios under a common impedance convention. The unwanted component's own absolute attenuation is $|H({\omega }_n)|$, which need not equal its attenuation relative to the wanted signal.

Cited experimental account: Figures 70–77.

Chapter IV; inspected §§70–75.

Chapter III, pp. 119–155; inspected §§61–64.