Confused New User

Discussions and question about the general functionality of RadiMation
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GeoffW1952
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Joined: 22 Feb 2018, 13:28

Confused New User

Post by GeoffW1952 »

I am somewhat confused. Gain (and Correction) are positive dB? Attenuation, Insertion Loss (and Correction) are positive dB? What is the equation that Radimation uses to relate these correction file entries to the displayed graphical output and table?

According to the Radimation Wiki page and the section on Cable: Cable loss the Gain correction factor (+) is inverted, so that Measured Signal Level + (Attenuation - Gain) = Output level displayed.
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joro
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Re: Confused New User

Post by joro »

I understand your confusion, but please let me explain:
Correction files in RadiMation are used for several purposes, and depending on the situation where a correction file is used, the contents can be interpreted differently.
In the past, a correction file only had 2 columns: A frequency column and a correction column. Nowadays a correction file can have multiple columns, and the type of the second column can be modified (by pressing on the 'Columns/Units' button on the correction file window). ( http://wiki.dare.nl/wiki/index.php/Chap ... tion_files )

In Chapter 14 it is described which correction files can be used to correct a cable loss ( http://wiki.dare.nl/wiki/index.php/Chap ... Cable_loss )

Because of history, the correction file that can be attached to a cable, can have a frequency and a correction column, where the values in the correction column are interpreted as cable loss. The positive values in the correction column are thus interpreted as dB values as a cable loss, a cable attenuation.

Once we added the possibility to select an 'attenuation' column in a correction file, it became possible to attach a correction file to a cable that contained a frequency and an attenuation column. The positive values in the attenuation column are then interpreted as dB values as a cable loss, a cable attenuation.

Once we added the possibility to select a 'gain' column in a correction file, it became possible to attach a correction file to a cable that contained a frequency and a gain column. Gain is of course the inverse of attenuation, and thus a different interpretation of the values in the gain column is done. The positive values in the gain column are interpreted as dB values as cable gain. These values are inverted to represented a cable attenuation (cable loss), before they are used to correct the cable.

This indeed results in the formula that you specified: Output level displayed = Measured Signal Level + Cable correction Attenuation - Cable correction Gain

I hope that this resolves your confusion.
Otherwise please let us know.
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joro
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Re: Confused New User

Post by joro »

One additional note:
Please be aware that the previous post describes the situation for correction files that are attached to a cable.
Correction files that are attached to a pre-amplifier are interpreted differently ( http://wiki.dare.nl/wiki/index.php/Chap ... ifier_Gain )

For a pre amplifier, if the correction file contains a Frequency and a Correction column, the positive values in the correction column are interpreted as gain values.
GeoffW1952
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Joined: 22 Feb 2018, 13:28

Re: Confused New User

Post by GeoffW1952 »

Many thanks for the clarification. It helps me a great deal :)
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