# Questions tagged [envelope]

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17 questions
0answers
17 views

### How to get the amplitude output of a single frequency from a Resonant Bandpass? (ie. Using a reso BP as an envelope…)

A resonant bandpass like this: is resonating at a frequency of 125 Hz. You are controlling the decay time by modulating $Q$ accordingly. The BP is being excited by a MIDI triggered impulse. At its ...
1answer
22 views

### How does the power spectrum of the amplitude envelope depend on its underlying carrier frequency?

when looking at the amplitude envelope of an oscillation (see red trace in Figure below), it seems to me as if the frequency content of the envelope depends on the the frequency of the underlying ...
1answer
26 views

### How to change the shape of a function generator keeping the rate?

I'm making a sort of Envelope Function Generator. At the moment, I'm calculating only the the "rise" stage, which goes from 0 to 10 V; than, brutally, I back it to ...
2answers
126 views

### Bandpass filter that automatically adapts its bandwidth when a transient is detected (to avoid to smoothen the transient)

Let's say we want to isolate a band 1000 hz +/- 50 hz. Obviously, limiting the bandwidth by applying a passband filter will always destroy a bit the sharp transients (a Dirac or a rectangular ...
0answers
25 views

### how to robustly estimate low and up envelope of signal with trend, few level constant steps and noise

I am looking for robust estimation method of low and up envelope of the signal consisting from smooth trend component, constant steps between few fixed levels and additive noise (+ outliers of course)....
2answers
762 views

### What is a constant envelope modulation?

The Book "Digital Modulation Techniques" by Fuqin Xiong groups digital modulation schemes into two classes: "constant envelope" and "nonconstant envelope." However, I was surprised by the inclusion ...
1answer
75 views

### Is it possible to get the envelope of a signal via FIR filter?

I was reading an article about ultrasonic signals, and I read in it that it is possible to get the envelope of a signal by using a band pass FIR filter. My question: Is it possible to get the envelope ...
2answers
397 views

### Extracted envelope via Hilbert Transform is tracking the signal

I am trying to extract the envelope of the signal shown in blue, which is the low-pass filtered output of a second-order system. Low-pass filtering was done in order to reduce measurement noise. To be ...
1answer
425 views

### Signal envelope

I have a relatively low-frequency signal and want to calculate the peak envelope of it in Simulink. I tried some of filters but the envelope is not well precise. can anyone help, how can I do it?
1answer
289 views

### Recover IQ samples from signal

I have a data acquisition device that provides me with an array of integers that represents a modulated signal (let's say QAM16). I would like to recover the I and Q samples from the raw time-domain ...
1answer
92 views

### Obtain the complex envelope of a two-tone signal

I know it is possible to represent a single-tone signal by its complex envelope: \begin{align} x(t) &= A(t)\cos(2\pi f_c t + \Phi(t))\\ x(t) &= \operatorname{Re}\left\{A(t)\mathrm{e}^{j \Phi(...
1answer
253 views

### How to recover a signal from its complex envelope

I know there's similar questions here, but I did not fully understand the answers I have read: in MATLAB I consider the complex envelope of an output signal: ...
3answers
2k views

### How can I plot the spectrum of a signal in MATLAB?

Consider an input signal x_total and the complex envelope of an output signal y_total in MATLAB: ...
1answer
577 views

### What is the IMAL envelope method?

"Envelope methods" can be used to describe and predict the output characteristics of a highfrequency non-linear amplifier such as a travelling wave tube. Apparently one of these methods is known as ...
1answer
143 views

### How can I describe a sum of sinusoids by an equivalent lowpass signal?

I consider a sinusoidal signal with fixed amplitude $A_{\rm in}$ and frequency $f_c$. This signal is sent into a nonlinear amplifier, whose AM/AM and AM/PM characteristics are known. Using these ...
1answer
719 views

### What are the different ways to find the envelope of a speech signal?

I am new to signal processing. I want to find the envelope of a given speech signal. When I searched about it, I found about Mean Hilbert envelope function. I want to know what other functions/...
4answers
6k views

### Equal power crossfade

I am working on an audio system where I need to implement an equal power crossfade between two signals over a specified number of samples. Initially I implemented a linear fade but this creates a dip ...