To create a sinusoidal signal, you will be asked to enter amplitude (A), frequency (F in Hz), and phase values (PHI in degrees) for each trace to create. To ceate a cosine, enter a phase value of 90 degrees.
Using this option, you can create spiky test signals consisting of multiple or single spikes of different amplitudes at different positions. Enter the indeces of a spike positions in the upper and the corresponding amplitudes in the lower input panel.
This test signal is a simple single value function. The user will be asked for the value to apply to every point of the test signal.
One can create a test signal corresponding to the displacement puls from a Brune earthquake source model (Brune, 1970) with RTH being the radiation pattern, sigma being the stress drop in bars, mu being the shear modulus in Pa, vs the shear velocity in km/sec, and r and z being the source radius and the hypocentral distance, respectively, in km. In the formula above, the free surface is taken into account by a factor of 2 (SH waves).
The mixed signal is a superposition of a sinusoidal, an exponential and a linear function in order to help the user create a very general type of test signal. DST prompts for the amplitude A, frequency F, phase term PHI, and constants B, C, and D.
The Ricker wavelet is a zero phase wavelet which is the second derivative of the error function. The user has to enter the dominant frequency in Hz.
Use this option to create test signals simulating the response of a seismometer to different input signals. Different types of signals can be selected:
-> Displacement impulse -> displacement response: Actual impulse response of a displacement seismometer.-> Acceleration step -> displacement response: Theoretical response of displacement transducers to a step function in acceleration (release test).
-> Acceleration step -> velocity response: Theoretical response of electrodynamic transducers to a step function in acceleration (release test).
These last two kinds of signals can be generated in seismometers with additional calibration coils by turning off (or on) a constant calibration current.
After selecting the signal type, you will be prompted for the eigenfrequency in Hz and the damping factor for the seismometer to simulate. The input signal is assumed to act at time zero.
In all cases the user is prompted for the seismometer eigenfrequency in Hz and the fraction of critical damping (<1.).
The chirp signal is produced by linearly increasing the frequency of a sinusoid between two frequencies F1 and F2. The user is prompted for the amplitude A, the lower frequency F1, the initial phase term PHI , and the higher frequency F2.