Signal Processing
| 2D Image Contour Plot | |
| Platform | LabVIEW 7.1 |
| Introduction | It is used to generate the contour plot of a 2D intensity graph (such as spectrograms) in dB unit. The contour level and increment (in dB) can be controlled to satisfy the visual investigation. |
| Update | Aug 11, 2005 |
| Undistorted IIR Filter | |
| Platform | LabVIEW 7.1 |
| Introduction | Signal after filtering often includes some border distortion. The IIR filtering together with the projection initialization is used to reduce these effect. This utility is extremely useful for short-length signal filtering. |
| Update | Aug 16, 2005 |
| Spectral Subtraction Based Time Varying Filter | |
| Platform | LabVIEW 7.1 |
| Introduction | The time varying filter is implemented in three steps: Gabor transform, spectral subtraction and Gabor expansion. It can be applied to the noise reduction in time varying harmonic signals. (Refer to Doppler ultrasound spectral enhancement using the Gabor transform based spectral subtraction. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control) |
| Update | Mar 10, 2005 |
| Cohen's Time-Frequency Distribution | |
| Platform | LabVIEW 7.1 |
| Introduction | This function is used to compute some Cohen's time-frequency distributions (WVD, BJD, CWD, CSD, MHD, PWVD, Page, KRD and Spectrogram). The input signal can be real or complex. Because of the large computational complexity, don't input a long signal. |
| Update | Oct 24, 2004 |
| Doppler Ultrasound (US) Signal Simulation | |
| Platform | LabVIEW 7.1 |
| Introduction | This function is used to simulate audio Doppler US signals from blood flow. The sample volume (SV) can be chosen between the spherical and the cylindrical. For the spherical SV, you can set the center of SV with some offset. (Refer to Yu Zhang, Hong Zhang and Nanxiong Zhang. Microembolic signal characterization using adaptive chirplet expansion. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control) |
| Update | Sep 28, 2004 |
| Empirical Mode Decomposition (EMD) | |
| Platform | LabVIEW 7.1 |
| Introduction | The empirical mode decomposition can adaptively decompose the input signal into a set of intrinsic modes. The following Hilbert spectrum can be used to investigate the frequency component variation. This algorithm can be also used in adaptive trend estimation. |
| Update | Aug 14, 2004 |
| Adaptive Notch Filter | |
| Platform | LabVIEW 7.1 |
| Introduction | It can be used to adaptively cancel the noise of power line frequency (50Hz/60Hz). The algorithm used in this function is the normalized LMS method. The residual noise level in the result can be controlled by the step size: the noise level is proportional to the step size. |
| Update | Jul 30, 2004 |
| Modulus Maxima Detection of Continuous Wavelet Transform | |
| Platform | LabVIEW 7.0 |
| Introduction | The modulus maxima of continuous wavelet transform are often used to characterize the singularity property of the input signal. This function can detect these local maxima according to the scale setting and ignore some fake maxima. |
| Update | Jul 30, 2004 |
| Digital Filter Frequency Response | |
| Platform | LabVIEW 7.1 |
| Introduction | The magnitude and phase response of a digital filter can be computed by this function. The magnitude response can be logarithmic (dB) or linear, while the phase response can be wrapped or exactly unwrapped. |
| Update | Jul 18, 2004 |