The article considers a parametric effect which takes place when the velocity of signal propagation in a long line changes. We found the analytical solution describing the form of the transformed signal for a line with losses, when line parameters change symmetrically. We also considered lines without losses, with asymmetrical change of parameters. Our theoretical results comply with experimental data. In certain conditions, such a line can be used as an amplifier. The parametric effect in optics is described by Maxwell's equations, while in case of a long line, the analysis is based on telegrapher's equations. However, it turns out that in the end, both in optics and electronics, the parametric effect is described by wave equations that are mathematically similar. This is because fundamentally, the parametric effect is physically based on energy interchange between the controlling (pump) signal and the transformed one, when the parameters of the propagating medium change. So, the obtained results can be used for analysis of parametric effects in optics and electronics.

Distributed Parametric Effect in Long Lines and its Applications

The signal-to-noise ratio of radio astronomy receivers can be optimized and the sensitivity improved by reshaping the waveform of the signal received from the antenna by processing it through a transmission line in which the velocity of propagation can be made to vary as the signal enters or leaves the line. Presented here is the complete analysis of the determination of the minimum detectable temperature in the case of a total power radiometer incorporated with time-varying transmission lines. A comparison of the two sensitivity figures of the total power radiometers with and without such transmission lines is also given.

A method for the sensitivity improvement of radio astronomy receivers

The article considers a parametric effect which takes place when the velocity of signal propagation in a long line changes. We found the analytical solution describing the form of the transformed signal for a line with losses, when line parameters change symmetrically. We also considered lines without losses, with asymmetrical change of parameters. Our theoretical results comply with experimental data. In certain conditions, such a line can be used as an amplifier. The parametric effect in optics is described by Maxwell's equations, while in case of a long line, the analysis is based on telegrapher's equations. However, it turns out that in the end, both in optics and electronics, the parametric effect is described by wave equations that are mathematically similar. This is because fundamentally, when the parameters of the propagating medium change, the parametric effect is physically based on energy interchange between the controlling (pump) signal and the transformed one. So, the obtained results can be ...

Distributed parametric effect in long lines and its applications

The impulse response and bi-frequency system function ore found for a variable-velocity transmission line with arbitrary velocity function. The case considered is a lossless line with constant characteristic impedance. It is shown that the input-output relationship takes the form where υ(t) is the velocity function and τ(t) is the solution of the equation.

G. J. M. Aitken

Papers

A method for the sensitivity improvement of radio astronomy receivers

The impulse response and system function of a variable-velocity transmission line †