Vasona Training- Module 3, Specification Limits

[EMiSoft Home] [Site Map] [EMC Information] [FTP Site] [Contact]

Purpose

This training modules steps you through "Specification Limits" and how to deal with them, including:-

Important Points
Spec Limits : Updating Values
Creating Specification Limits
Specification Limit Selection

Specification Limits : Important Points.

Steps
Enter steps in the specification limit, at the same frequency. Vasona works out the correct amplitudes. See the example below at 230MHz.

Number of points
Dependent how you configure Vasona, the specification limits used may be limited to the number of points which the analyser can accept, ie for the HP8546A this is 24points.

Frequency Order + Zero
Points need to be entered in frequency order, a sort facility is available, or click on the Frequency Label. In addition, files should not contain a 0 in the frequency column, the Log of 0 is not a valid number.

Type
Vasona currently supports only Average and Quasi Peak Limits. Note: in debug mode you can do peak measurements.

Measurement Distance
The setting of measurement and specification distances is very important, if these values are different, Vasona will apply the difference using the following formula:-

Extrapolation	= 20*LOG [measurement distance / specification distance]
for example	= 20*LOG [3/10] = -10.46dB. Vasona will take this value into account when calculating results.

Log Frequency Scale
Only limits which change with the Logarithm of Frequency can be input. If you require the use of linear limits, calculate the intermediate amplitude values and then enter them if they were Logarithmic. Note this only matters if the amplitude of the limit changes with respect to frequency.

Update Specification Limit

Function

Form

Description

Select Menu + View Limits

Main Menu

Click on the View Details button.

Select the Limit TAB. You will then see a selection of limits.

Select Limit

Main Menu +
DataSET

From these limits, move your mouse over the one you want to edit, right-mouse button click, select "Edit File".

The DataSET manipulation window should now be displayed.

Note: you can see from these options that you can perform other functions:-

1. View the relevant file.
2. Edit, change and update the contents.
3. Open a completely new file.
4. Rename the existing file.
5. Delete the file altogether.
6. Look at various properties of the file.

Save file
DataSET

DataSET

Save DataSET From within DataSET do the following:-
1. From the menu bar select File.
2. Select option "Save".

Creating Specification Limits

Function

Form

Description

Select Menu +
View Limits

Main Menu

Click on the View Details button.

Select the Limit TAB. You will then see a selection of limits.

Open DataSET Menu

Main Menu +
DataSET

Right mouse button click within the ICON display section. Then select "Open New File".

The DataSET manipulation window should now be displayed.

Select File Type

DataSET

Update the file type with Specification Limit- Quasi Peak.
	Note that the Quasi Peak Limit Icon will appear !

Update DataSET

DataSET

	Enter the title of the limit, for example "RE - EN55022". ie Radiated Emission for the specification EN55022.
	Set 'Amplitude Units' to dBuV/m. It is important to get this correct because these labels appear on graphical / tabular output.
Set level to "A". Set Distance to "10". If the measurement distance is set different, Vasona will automatic extrapolate the results.
The following example shows a measurement distance of 10m, to change, click on the 10 and enter a different value, ie 3.

Update Values in
DataSET

DataSET

	Click in the frequency box, where the value .000 appears. Enter the relevant Value
	Type in 30, hit arrow key right '>' , then enter the relevant amplitude/level.
	Press arrow key right '>' twice, then add a further frequency... and so on....
	Continue with this process till you have added all you points.

See Important points for further information.

Plot from within DataSET

Upon completion of the DataSET input it may be useful to plot the points to view if you have made any mistakes. To do this perform the following:-

1. Select Tools from the menu bar.
2. Select Plot.
3. Select Log.

A plot will now appear, see the following example.

Save file
DataSET

DataSET

Save DataSET From within DataSET do the following:-
1. From the menu bar select File.
2. Select option "Save".

Selecting Your Specification Limits

Function

Form

Description

Open Vasona, and do NOT run a template, you can select a new specification limit once a test has begun but we recommend this only for experienced users !.

Select Menu + View Limits

Main Menu

Click on the View Details button.

Select the Limit TAB. You will then see a selection of limits.

Drag Limit

Main Menu

	Left mouse button click on the limit icon and drag it to the Upper Limit. Note: you drag Quasi peak limits to the Upper space/area in the spectrum analyser display and the Average limits to the lower display.
	The next time you run this template this specification limit will be used. If there is a Limit symbol there, this will be updated once you have dropped your new limit in !.

Verification of which limit is loaded.

Main Menu

	Move your mouse over the Limit icon within the "Spectrum Analyser Diagram" and your limit should be displayed in the Menu details.
	To view the contents of the specification limit, do the following:- 1. Move mouse over the limit symbol. 2. Right Mouse button Click. 3. Select "View File" 4. The DataSET window should appear You can now look at the actual values.

Congratulations, you now know how to deal with
Specification Limits within Vasona !!!'
Return to the Support Menu