Module, Fine Tune

Purpose
This training module covers the "Fine Tune" methodology, which is required to ensure that the frequency of the captured peaks is accurate.  If this is not the case, then when Vasona attempts a quasi peak or average measurement, it may not give you accurate results.

Spectrum analysers do not provide accurate frequency measurements when data is captured in large spans.  We need to make these types of measurements to speed up the process, hence you must fine tune the frequencies prior to formal testing. 
Information
Step Function Form Description
1. Select Frequency Results From the debug table highlight the first [or relevant frequency].  This is achieved by placing the mouse over the frequency and then 'right mouse button' clicking.

Debug Signal, Set Analyser to given defaults

In this selection, we have chosen the first signal on the list, to complete the process ALL signals must be fined tuned.

The following process occurs, the centre frequency of the analyer will be set to 200.008MHz with a span of 2MHz.   The analyser will also be configured using the relevant transducer factors, specification limits, reference levels.......   etc.

It is likely that the emission in or around 200.008MHz will not be at the center of the screen, see frequency accuracy of spectrum analysers for further details.

2. Select Frequency Results The objective is to update the frequency of the emission in the list.  If you have a small analyser span, say 2MHz, this will ensure this accuracy.

You need to use various  functions of the spectrum analyser facilitate this, the typical ones required are given in the control panel, under the debug TAB.

Analyser Control Functions

Clicking on the "update freq button" reads the current analyser marker frequency and updates the current list.

Now manipulate the analyser so that the "current marker" is on the relevant frequency and click "update".

Overview of functions
Marker Peak Functions:
Sets the analyser marker to the following:- Peak, Next Peak, Next Peak Right, Next Peak and Current Marker to center frequency.
Marker Counter: Counter on/off at the current marker frequency, Marker Audio: Audio on/off at the current marker frequency
Sweep: Set the analyser to single/continuous sweep mode.
Mode: Clear write or sets Max hold on the current active trace
Res Bw: Scrolls the Resolution bandwidth or the analyser.
Span: Increases/decrease the current span
Scroll: Increase/decrease the start and stop frequencies by the current span, ie

Analyser

  

Analyser

Start Stop

Operate Scroll
[UP]

Start Stop
32MHz 34MHz

>>>>>>
>>>>>>

34MHz 36MHz

 

   Results Typical operations, begin from the first and work through them.

First Set the polarity of the antenna to that shown in the list.
No Problems Solution
1 Signal not at center of span but still visible.  >Marker to peak
 >Update List
2 Signal not visible.  >Scroll Up
 >Peak Found: Yes
 >Marker to peak
 >Update List
3 Signal not visible.  >Scroll Up
 >Peak Found: No
 >Scroll Down [twice]
 >Peak Found: Yes
 >Marker to peak
 >Update List
4 Signal not visible. If steps 2-3 fail increase no of scrolls to 2 and re-check  frequency range.


If steps 2-4 fail to find the frequency, set center frequency of analyser to 200.008MHz, and change Antenna polarity, Antenna Height and Turntable azimuth.  Then repeat process.

5 Two signals found [similar size].  >Instruction to be added.

 

3. Next Frequency Results Select next emission in the list, this can be achieved by moving the mouse over the desired frequency, 'right' mouse button clicking and selecting 'set centre frequency'

Set Centre Frequency on the Spectrum Analyser

This will just set the centre frequency of the analyser to that in the list, namely 216.119MHz. If the configuration set of the analyser is significantly different between frequencies, then you are advised to select "Debug Signal".

Repeat process of fine tuning.
4. Process Results Repeat this process of fine tuning until all frequencies have been updated.
5. Store Data Results
+
Save Results Window
vasona13.gif (8415 bytes)

To re-store the current debug data:-

1. Click on the 'Info' Tab
2. This is the name of the current file.
3. Click on the 'save button' this will bring up the "Save Results Window".
Update Test Results

On this form click on the "Update File" button to  re-save the test data.


Note: box 2 will display the title once the data has been saved.

The other details....
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