This applet explores the use of limiting summation/successive detection approaches to the design of power-law or logarithmic compression amplifiers.
The plots compare the accurate curve to the linear segment approximation arising from this design process.
The Number of Stages, Dynamic Range and Minimum Level values determine the design accuracy. Minimum Level entry refers to the start of the law approximation.
Corresponding gains and stage limiting levels for the current design are listed on the display.
The Stage Gain Error and Limiting Error parameters show the effect of gain and limiting level errors on the wanted characteristic. The figures are applied to all gain stages equally.
Moving the mouse in the voltage in/out space displays the plotted levels related to the x-axis mouse data value. Note that, 0 dBmV ≡ 1 mV; 20 dBmV ≡ 10mV.
Default values may be modified and the display updated using the applet scrollbars or keyboard Enter key.

User Notes:
The peak error listed is half the peak-to-peak value. Should practical amplifier stages have a smooth limiting knee, peak error values less that calculated may be observed.
When designing power-law or logarithmic amplifiers for microwave detectors, the detector compression characteristic itself needs to be matched. In the first instance, it is usual to produce separate matching error designs for the square and linear regions, before combining and tuning for an optimum result.