I was wondering if there was a way to write a function to calculate the trajectory of a sine wave in MATLAB? Any help would be greatly appreciated.
I encountered this same ambiguous question in my MATLAB homework (maybe we're in the same class?). It's very unclear what the question is asking so I had trouble figuring it out too. I ended up trying random sine operations and soon found that the trajectory of the sine wave (T) over time (t) is as follows:
T = sin(t)
As simple as this answer is, I'm not entirely sure why it is correct. I don't usually like giving straight answers but in this case the question is so ambiguous that OP probably wouldn't be able to find the solution without resorting to random guessing like I did.
Related
This is a question that possibly borders on the intersection of the general usage of MATLAB and/or signal processing. Thought I would first ask the question in a MATLAB forum before trying signal processing.
So our lecturer read out his notes/paper and said the equation
could be implemented as a filter.
At first, it seemed difficult to follow the idea but when realizing that integration is same as finding areas under the curve which seems similar to applying a low pass filter so that only the portion of the signal under the threshold is allowed to pass through, it made a bit of sense. But how - meaning to say which function - can I use to implement the above equation? Do I need three filters or can I use just one? How do I use the terms preceding the integrals in the filter?
Thanks in advance
I am trying to get an envelope for a spectrum I measured.
I have used the hilbert function in MATLAB which works for a dummy function I wrote,
but it does not give the correct result for my spectrum. (I got back the exact same curve).
I am thinking the oscillation of my spectrum is too fast but not too sure on this.
Hope someone can tell me what is wrong here.
A=xlsread('test.xls');
y=A(:,2);
h1=imag(hilbert(y));
E=sqrt(y.^2+h1.^2);
I intend to generate a square wave which is applied on a DSP.
I have written these codes and put them in an embeded Matlab function.
function y = fcn(u)
%#eml
t=0:0.001:1
h = sign(sin(125600*t+u));
y= (h+1)/2
where, u is a constant value of 0.582 which is used for shifting the square wave.
The problem is at the output in the simulation, instead of getting a square wave, I see only two straight lines of y=o and y=1.
Please let me know where is the problem that I can not get the square wave?
Note that the frequency of square wave must be 20 kHz. Therefore, I adjust the sampling time as 1e-7 s. And also its amplitude is between 0 and 1 In addition, due to this signal must be transferred to a DSP board, in the "solver option" I chose the type: " Fixed-step" and for the Solver: "Discrete (no continues state)".
Thanks a lot.
This is wrong on many levels.
First of all, you never define the time vector inside a MATLAB Function, that's what the Simulink engine does. Pass time as an input to your MATLAB Function block and use a Clock block to generate the time input.
Second, the above is fine for simulation, but it sounds like you are generating C code from the Simulink model to run it (in real-time) on your DSP. This is not my area of expertise, but from memory, I think you need to enable "absolute time" or something similar for the above to work with code generation. However, I think this is target-dependent and so I'm not sure whether this will work on your DSP.
In you function type plot(t,y) at the end. You are generating a 20khz square wave (assuming you are sampling at 1e-7). Essentially your generating it is working.
Now, what is the DSP board you are using/any information that is relevant to your problem?
I don't know what you are referring to when you say "Solver" either.
Is the "simulation" an oscilloscope or a program? Either way perhaps it is not triggering correctly? Is there an edge trigger option?
He all! I'm very new at matlab and I have a simple question to ask: I have a function that is being evaluated at 100 discrete points. I can get it on a plot using:
plot(x,f,'+')
But I need to print an actual list of these values.
Does anyone know how I could do this? I've searched without any luck, even though this seems fairly trivial
I'm looking for some functions in MATLAB in order to find out some parameters of sound,such az intensity,density,frequency,time and spectral identity.
i know how to use 'audiorecorder' as a function to record the sampled voice,and also 'getaudio', in order to plot it.But i need to realize the parametres of a sampled recorded voice,that i mentioned above.i'd be so thankful if anyone could help me.
This is a very vague question, you may want to narrow it down (at first) and to add as much contextual details as you can, it will certainly attract a lot more answers (also as mentionned by Ion, you could post it at http://dsp.stackexchange.com).
Sound intensity: microphones usually measures pressure, but you can get the intensity from that quite easily (see this question). Your main problem is that microphones are not usually calibrated, this means that you cannot associate an amplitude with a pressure. You can get sound density from sound intensity.
Frequency: you can get the spectrum of your sound by using the Fast Fourier Transform (see the Matlab function fft).
As for spectral or time identity, I believe these are psychoacoustics notions, which is not really my area of expertise.
I'm no expert but I have played with Matlab a little in the past.
One function I remember was wavread() to input a sound signal into Matlab, which if executed in this form [Y, FS, NBITS]=WAVREAD("AUDIO.WAV") would return something like:
AUDIO.WAV:
Fs = 100 kHz
Bits per sample = 10
Size = 100000
(numbers from the top of my head)
Now about the other things you ask, I'm not really sure. You can expect a better answer from somebody else. I think this question should be moved to Signal Processing SE btw.