H/V spectral ratio
This tool is used to obtain Horizontal to Vertical (H/V) spectral ratios from any type of vibration signals (ambient vibrations, earthquake…). The example used for explanations is an ambient vibration recording.
Contents
Getting ready
- Download compressed signal file.
- Load and view these downloaded signals.
- Select H/V in menu Tools (alternative ways to start a tool)
Window selection
- Make sure you are in the Time tab, and that parameters are as in the example window.
- Click on the Raw signal, to check that anti-trigger parameters are as in the example window.
- Click on the Select button and select Auto.
- The number of selected windows appears at the bottom right corner of the time tab.
The number of windows should be as in the example.
- Selected windows should appear as green rectangles on the signal viewer.
Processing parameters
- Click on the Processing tab, and make sure that parameters are as in the example window.
Output parameters
- Make sure you are in the Output tab, and that parameters are as in the example window.
Data processing
- Click on Start button at the bottom of the toolbox, whatever tab is displayed.
- In case no window selection has been performed, a pup-up window appears.
Simply click on the Yes button and processing will follow its way.
Results
Signal diplay
- Selected windows are colored, matching colours in he H/V graphics, i.e. colour of indidual H/V curves have he same colour as the signal windows.
H/V curve
- The blak curve represents H/V averaged over all colored individual H/V curves The two dashed lines represent H/V standard deviation.
- The grey area represent the peak requency and its standard deviation. The frequency value is at the limit betwen the dark and clear areas.
- Use the cursor to get values on the H/V curve. The exact value of the frequny of he H/V peak and its standard deviation may be obtined y sliding the rsor no he H/V curve title.
The toolbox may be opened in two different ways:
- if the signal window is already open clik on the H/V icon
- if the signal window is not open drag the file(s) from the file manager to the H/V icon
The toolbox shows up in the form it was previously closed, with the file name(s) in the header.
The toolbox contains set ups for windowing selection and processing, together with output parameters.
Comprises three tabs: 
Time tab
Divided into three parts
Global time range
Used to select all or part of the signal to be processed.
Works like the Waveform/Cut basic signal processing under the Waveform menu.
When "Use only the properties of the first signal" is checked, all tracks use the time parameters (T0, End, Picks) of the top track.
Time windows
Comprises 4 tabs: 
Windowing results
Below Time windows a line gives the resulting selected windows, in all stations, with possibility to get the number of windows in each station through the View pop-up menu.
