[Kst] X-axis time scale to match sample rate

Ben Lewis ben.lewis at egretengineering.com.au
Wed Oct 14 23:43:16 CEST 2009

Hi Andrew,

Thanks for your help. Your instructions worked perfectly.

Regards, Ben

Andrew Walker wrote:
> Hi Ben,
> There is no simple way but the following works well.
> The basic idea is to create a equation that scales the INDEX vector by 
> the desired sample rate and then plots the y-vector against this.
> * Read in the data as usual
> * Create a new equation: Data...New Equation...
> * In the "New equation" dialog enter the following in the "Equation" 
> field:
> [INDEX]*<scale>
> where <scale> is the desired sample rate (e.g. [INDEX]*5.0)
> * Select "Do not place in any plot" and hit "OK"
> * Create a new curve: Data... New Curve...
> * For the "X axis vector" select the output of the new equation: 
> "INDEX*<scale>/sv" (note that it is /sv and NOT /xsv)
> For the "Y axis vector" select your usual y-axis vector
> * Click "OK"
> This should produce the desired result.
> Andrew
> ----- Original Message ----- From: "Ben Lewis" 
> <ben.lewis at egretengineering.com.au>
> To: <kst at kde.org>
> Sent: Tuesday, October 13, 2009 7:57 PM
> Subject: [Kst] X-axis time scale to match sample rate
>> I have an application where I log data multiple times per second.
>> Each line in the data file contains variable data only (i.e. no time
>> data is recorded).  Time data is not needed as I know the test start
>> time and the sample rate.
>> When I read a data file into KST I use the option to "interpret INDEX as
>> INDEX".  I then plot the variable data (y-axis) against the index value
>> (x-axis).
>> I would like to be able to plot test data on a time scale rather than an
>> index scale.  I cannot see an option to enter the sample rate.  What is
>> the  recommended procedure for doing this?
>> Regards, Ben
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