What is the equivalent of PlotY method in WPF?

Hello,

I want to draw a spectrum analyzer data on a graph. My graph  XAxes contains Frequency (MHz) and YAxes contains Amplitude (dBm).

I have a data equivalent to graph resolution width approximately 1800 (data[1800]). 

Graph start from 750 MHz and end 1250 MHz. When I want to draw data it always start 0 and end 1800. How can I accomplish this task?

In WinForms we had a PlotY method as follows and it enables us to produce desired output. What is the equivalent method in WPF?

publicvoid PlotY(double[] yData, int startIndex, int length, double start, double increment);

 I have attached  two screenshooots which represents desired and actual graph representation respectively.

I also added my code.

Thanks in Advance,

Hakan,