SLWU087E november 2013 – june 2023
The FFT power spectrum of the captured data is displayed in the major center portion of the window. The HSDC Pro GUI software automatically scales the horizontal axis from DC through the Nyquist frequency, although the scale of the horizontal axis can be changed simply by highlighting the text and typing in a new value. For example, the display in Figure 3-29 can be used to zoom in on the input frequency by highlighting the 0 MHz at the end of the spectrum and typing 25M, and then highlighting a value at the other end and typing in 35M. This causes the portion of the power spectrum from 25 MHz through 35 MHz to fill the power spectrum display.
The vertical scale of the power spectrum is automatically scaled to display the noise floor of the FFT result up through 0 dBFS. The vertical scale can also be manually adjusted by highlighting the limits of the vertical scale and typing in new limits. By default, the first few harmonics of the input frequency are marked in the display, as well as 2 additional marker, M1 and M2, that can be placed by dragging the marker to any place in the power spectrum, such as a noise spur that is not already marked as a harmonic.
Display properties can be edited by using the mouse to right-click in the power spectrum display. Visible properties such as the graph palette or plot legend can be edited, and auto-scale of the vertical and horizontal axis’s can be enabled or not. The data can also be exported to Excel or a clipboard for coping or processing.