 Still in my Bachelor of Electrical Engineering. I'm new to signal processing, but trying my best. I'm doing a project right now and try to get used to MATLAB.

## Re: Digital Modulation Methods

Yeah, the constellation diagram is the first part of the task. The modulation symbols have to be labelled as you can see in the photograph. But I have no clue about...

## Digital Modulation Methods

So I'm currently working on preparatory lab tasks, which, unfortunately, I cannot solve. For an 8-PSK modulation I consider the bit sequence 011 111 001 000 ,...

## Re: Complex envelope and analytic signals.

you're right, I messed up the frequencies. I have corrected it in my original post.Unfortunately, the phases are still not equal.t is a vector of time, but for the...

## Re: Complex envelope and analytic signals.

allright, thanks Fred! - I have edited my question and I hope it is more clear now - although I admit the code lines look a little confusing

## Complex envelope and analytic signals.

I can't get my head around the complex envelope and analytic signals. I know I have asked this before, but I considered the problem again and to me it hasn't been...

## Re: Normalization in the context of nonlinear amplifier curves

thx very much, it does help!

## Normalization in the context of nonlinear amplifier curves

The AM/PM curve of a power amplifier gives the difference in phase of the output and the input signal in dependence of the input power/ amplitude. Now, this phase...

## Re: What is the difference between the Fourier transform of an analytic signal and the one-sided Fourier transform?

Thanks Fred, this really helps! But I am still a little bit confused: Since you asked for a definition of the one-sided Fourier transform, I started looking...

## What is the difference between the Fourier transform of an analytic signal and the one-sided Fourier transform?

The spectrum of an analytic signal equals twice the spectrum of its real part for positive frequencies and it is zero for negative frequencies. Now, I wonder: When...

## Re: AM/PM of a RF power amplifier

Did you mean to ask me that question? I don't see the link to my original question. And I have no clue about it. I mean, I'm grateful if you are trying to give me...

## Re: How to create the equivalent lowpass signal of a multi-tone signal

I can extract the amplitude and the phase from the complex envelope representation. This can easily be done with abs() and phase() command in Matlab. I think it...

great, thanks !

## AM/PM of a RF power amplifier

The AM/PM characteristic of a RF power amplifier graphs the phase difference of the input and the output signal in dependance of the amplitude of the input signal. I...

## Re: Why do harmonics and intermodulation products occur in nonlinear devices?

Ya, I thought so too. It is kind of urgent now, however. Can you still explain to me where I find the AM/PM in my mathematical expression? I don't know what you...

## Re: Why do harmonics and intermodulation products occur in nonlinear devices?

ok, let me see: A power spectrum cannot have negative components. That means, with the sin(2wt) term, I am substracting a positive power. Leaving out this term...

## Re: Why do harmonics and intermodulation products occur in nonlinear devices?

so, does distortion mean "distorted from the linear transfer characteristic" ?

## Re: Why do harmonics and intermodulation products occur in nonlinear devices?

the sine-wave at 2wt is also phase shifted by pi/2. Is this the phase distortion ? .. If I would draw the power spectrum of the output signal, would the term at...

## Re: Why do harmonics and intermodulation products occur in nonlinear devices?

thx, this really helps! I have tried both with a sine and a cos two-tone signal: x(t) = sin(wt) + a * sin(wt)^2x(t) = sin(wt) + a/2 * (1 - cos(2 wt) ) x(t) =...

## Why do harmonics and intermodulation products occur in nonlinear devices?

Harmonics and intermodulation products do not occur in ideally linear devices. Why do they occur in nonlinear devices? I am referring to amplifiers. It must be linked...

## Re: Using matlab2tikz to include a Matlab vector graphic in a LaTeX document

this is a great answer, thx Michael!still, I have tried out the matlab2tikz script, which can be downloaded at Matlab File Exchange. When I create the figure in...

## Using matlab2tikz to include a Matlab vector graphic in a LaTeX document

I am trying to add a Matlab graphic to a LaTeX document. I know there are various ways of achieving this and I hope somebody here can explain it to me.  I have...

## Re: How to create the equivalent lowpass signal of a multi-tone signal

wow, this is so much input, thank you guys so much! This should be the correct result then: The equivalent lowpass, or complex envelope representation is often...

## Re: How to create the equivalent lowpass signal of a multi-tone signal

Ok. Sorry, I'm a little slow on this topic. If I understand correctly, by shifting a bandpass signal down to baseband, half of the information will be in the negative...

## Re: How to create the equivalent lowpass signal of a multi-tone signal

Thx Tim, I feel like I am slowly getting there, but I'm not quite there yet. So from your nice exponential formulas trick, I see that you are basically just shifting...

## Re: How to create the equivalent lowpass signal of a multi-tone signal

I don't know how to show that these signals are not equal, but here's my intuition: The original two-tone signal consists of two cos-waves at different frequencies....

## Re: How to create the equivalent lowpass signal of a multi-tone signal

Is this, what you mean by re-casting: Is this still the same two-tone signal then?

## How to create the equivalent lowpass signal of a multi-tone signal

I know I have been asking a lot about amplifiers, this will be the last question, I promise! So, any single-tone signal can be represented as an equivalent lowpass:...

## Re: harmonic distortion of a single-tone excitation

allright, thx! I don't have software to validate your answer, but it is what I figured.

## harmonic distortion of a single-tone excitation

I consider a single-tone input to a nonlinear amplifier. I know, the nonlinearity will produce additional harmonic components at the output. I also know, the amplitude...

## Re: Intermodulation distortion of a two-tone input to a nonlinear amplifier

allright, thx very much!

## Re: Intermodulation distortion of a two-tone input to a nonlinear amplifier

thanks for your reply, Tim! The paper is about TWTAs. And the formula is stated to be valid for a two-tone input. Let me see, if I understand your reply correctly:...

## Intermodulation distortion of a two-tone input to a nonlinear amplifier

I consider a two-tone input to a nonlinear amplifier. In a paper I have read (unfortunately I cannot upload the paper), there is a formula mentioned for the calculation...

## Re: How to create a vector graphic of a block model

allright, thanks so much!

## Re: How to create a vector graphic of a block model

hey, thanks for your answer! I have tried out both LibreOffice Impress and Inkscape. I have exported my Inkscape drawing as an .eps file. I have exported the LibreOffice...

## Re: Why do we want an amplifier to be linear?

So, I am currently working on a paper. I want to give a short introduction to ideal linear amplifiers. I was thinking about sth. like: An ideal linear amplifier...

## Re: Why do we want an amplifier to be linear?

ok, thank you talldsp!  So, my statement g P_in = P_out ist actually wrong. It has to be  g V_in = V_out instead.  Now, in this case I have another question:...

## Why do we want an amplifier to be linear?

An ideal linear amplifier relates the input power to the output power of a signal by a proportional gain factor.  Is this a valid statement? Anyways, since it...

## Re: How to create a vector graphic of a block model

allright, thanks! I will consider using TikZ, but since it's kind of urgent, I will probably stick with Visio then.

## How to create a vector graphic of a block model

Ok, this is not a question related to digital signal processing. Sorry about that. Maybe you can still help: I want to create the following three graphics myself: I...

## TWTAs as compared to SSPAs

I have a few ( I assume very basic) questions about high frequency amplifiers in satellite communication. So, the traveling-wave tube is an amplifier which can...

## Re: Preemphasis Filter Design

thank you so much, dudelsound! I finally got it. ... now I will have to find a way of implementing it in matlab.

## Re: Preemphasis Filter Design

ok. So, I hope I understand correctly: I want my filter to shift my nonlinear characteristics towards the center characteristic. E.g. the characteristic at f1 =...

## Re: Preemphasis Filter Design

yeah, sorry to be so unclear about my question, I had some troubles understanding the problem. I think I got it now: I want to characterize a nonlinear amplifier....

## Re: Preemphasis Filter Design

ok. I am given 5 different AM/AM characteristics (as a table, from which I can of course plot the figures). And I want to use Matlab in order to tell what results...

## Re: Preemphasis Filter Design

Alltogether, I am given the AM/AM characteristics at 5 different frequencies. So I think I can set up a modell describing the nonlinearity in the range of these...

## Re: Preemphasis Filter Design

you're right, the plot shows the AM/AM characteristic of a nonlinear amplifier and I am trying to linearize it using the "Poza Sarkozy Berger modell". You can find...

## Preemphasis Filter Design

Consider the following characteristic of a nonlinear amplifier for two different frequencies: I want to design a filter which shifts the green characteristic horizontally...

## Design a filter-nonlinearity model of an amplifier

Hey, I'm absolutely new to signal processing, so please take it easy on me when I say sth. stupid ;-)Consider the following problem: I'm given a multicarrier input...

Use this form to contact Lucky_12

Before you can contact a member of the *Related Sites:

• You must be logged in (register here)
• You must confirm you email address