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R&S dB Calculator - VSWR converter | Radioaficion Ham Radio

R&S dB Calculator - VSWR converter


R&S dB Calculator - VSWR converterRohde&Schwarz 1GP77

R&S dB Calculator

This application note is an extension to the application note “dB or not dB?” and comes with a free of charge software tool. The R&S dB Calculator can be used to perform calculations related to decibel. The tool includes a calculator for adding and subtracting an arbitrary number of power levels expressed in units of dBm and watt. A similar calculator is included for adding and subtracting voltage levels – correlated and uncorrelated. The tool further includes a converter for converting units such as dBm, dBW, dBV, watt and volt and a converter for converting linear power and voltage ratios to dB and vice versa. A VSWR converter is also included for converting reflection quantities such as VSWR, reflection coefficient, reflected power, return loss and mismatch loss.



30 dBm + 30 dBm = 60 dBm? It is well-known that it is not as easy as that. If we convert these logarithmic power levels to linear values, we get 1 W + 1 W = 2 W. This is 33 dBm and not 60 dBm. And already, we face some trouble: we just want to do a simple calculation, but we need to start thinking about the correct formulas and we need to start converting values. In fact, this is not difficult, but it can be annoying.

This application note can be regarded as a spin-off of the widely read application note "dB or not dB?" [1]. As an extension to "dB or not dB?", this application note supplies a software tool that can do a lot of calculations for you. This software enables you to add or subtract an arbitrary number of power levels - correlated or uncorrelated - and can also be used to convert power units from the logarithmic to the linear scale and vice versa. In addition, these calculations can also be performed using voltage levels instead of power levels.

Furthermore, you can use this software to convert linear power or voltage ratios to decibels or to convert a voltage standing wave ratio (VSWR) to other linear and logarithmic reflection units.

In detail, this application software comprises five independent calculation tools:

  • dBmCalculator: This tool helps to add or subtract power levels expressed in units of dBm or watts. (An ideal 3 dB-combiner is taken into account.)
  • VoltageCalculator: This tool helps to mathematically add RMS voltage levels.
  • UnitConverter: This tool converts power units and voltage units.
  • RatioConverter: This tool converts a linear power or voltage ratio to dB.
  • VSWRConverter: This tool converts between different reflection units such as VSWR and return loss.
Installation File for 32-bit operating systems
4.8 MB
Application Note - English Version
09.03.2012 0.6 MB

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