Getting envelope of noisy signal

1. How do you find the envelope of a signal?
2. What is the envelope of a signal?
3. What is envelope detection in ultrasound?

How do you find the envelope of a signal?

In the EMD algorithm, the upper and lower envelopes of signals are obtained by using two steps: 1) identify all the local extrema; 2) interpolate between extrema by a cubic spline [9]. The interpolative envelope includes the upper and lower envelopes.

What is the envelope of a signal?

In physics and engineering, the envelope of an oscillating signal is a smooth curve outlining its extremes. The envelope thus generalizes the concept of a constant amplitude into an instantaneous amplitude. The figure illustrates a modulated sine wave varying between an upper envelope and a lower envelope.

What is envelope detection in ultrasound?

In medical ultrasound (US) imaging, the envelope detection is a commonly used digital signal processing (DSP) technique to extract the magnitude of the oscillating broadband radio-frequency (RF) signals from the high-frequency echo carrier before any back-end processing (Chang et al., 2007).