the analysis, interpretation and manipulation of signals
0
votes
0answers
18 views
Filtering a frequency and its harmonics (Matlab)
I want to remove all the frequency components from a .wav file except those within \$\pm 25\$ of \$523 \ Hz\$ as well as its harmonics.
Attempt:
I used a high pass filter first to suppress ...
0
votes
1answer
16 views
Gaussian function power spectrum (Matlab)
I am trying to plot the power spectrum (\$|FT(f)|^2\$) of a Gaussian function, and overlap it with the theoretically expected spectrum calculated from the Fourier transform pair:
\$e^{-\alpha t^2} ...
0
votes
1answer
25 views
Autocorrelation of heaviside functions
I'm trying to find the expression that describes the auto-correlation of two heaviside functions u(t). I was told that the result must be 1/2, which makes total sense, as the power spectral density of ...
0
votes
1answer
29 views
Gaussian Function Fourier Transform (Matlab)
I am trying to write my own Matlab code to sample a Gaussian function and calculate its DFT, and make a plot of the temporal Gaussian waveform and its Fourier transform.
According to the FT pair:
\$ ...
2
votes
2answers
27 views
Band-pass filter with a given impulse response (Matlab)
I am trying to pass a .wav sound waveform through a band pass filter whose impulse response is given by
\$ h(t)=50u(t) \exp(-10t) \sin(2 \pi 440t), \$
I have imported the file into Matlab as ...
0
votes
4answers
53 views
Can I efficiently monitor sound card line in with a vu meter?
I'm trying to monitor some audio input to my desktop pc with a vu meter. I've connected to the line in, and it's just a bog standard on-the-motherboard sound card. I'm having a problem understanding ...
0
votes
1answer
44 views
How much accuracy can I get with RF / acoustic triangulation?
Lets say I wanted to track an object locally in 3D space. This object could be transmitting at low power. I could have 3 or more receivers in the same room as an object. How much accuracy could I ...
0
votes
1answer
53 views
Help comparator circuit for this PWM signal inverter
I have 2 signal (signal on the left) and how to combine those 2 signal into the signal on the right, I have try using lm 741 op amp, but unfortunately the output signal is different from the ...
-2
votes
0answers
30 views
What is the absolute phase and the relative phase, of a signal?
I need to know what is the absolute phase and the relative phase, of a signal? and why these phases are important in the signal processing?
1
vote
1answer
24 views
Approximation for high SNR
In Slide 6 of this PDF, it says that the performance of binary signaling is as follows:
I can understand the approximation for high SNR in the incoherent FSK and DPSK case, but how do we get the ...
0
votes
0answers
11 views
measuring the coherence between wearable sensors signals
I am trying to measure the coherence between two acceleration signals collected from two different wearable devices, smartphone and smartwatch, I am applying the Coherence (signal processing) and I ...
1
vote
3answers
50 views
Emulate the effect of a lock-in amplifier on a signal with a programming script
I'm working on a gas emission sensing project in the lab which requires the extraction of a signal in a really noisy environment. The features of interests of my signal are much smaller than the noise ...
0
votes
1answer
10 views
Multiple signals requires multiple filters?
So, this might seem rather basic, but I'm going to pose it in the hope that I can save some work. So, I have a series of electrodes that are sensitive to voltage fluctuations, but, before I pass the ...
0
votes
1answer
40 views
Detection of CAN bus signal direction
I trying to detect if a "dominant" state on the CAN bus is set from a specific CAN node. For this I place a "bridge" between the node and the bus.
I don't want to forward each frame with a ...
1
vote
0answers
27 views
Sources of online broadband RF energy data stream?
I am interested in finding recordings of broadband FM radio emissions, ideally in the marine VHF frequencies (156.0 and 162.025), in order to understand carrier artifacts and distortions that could ...
0
votes
2answers
53 views
Steady State Error: why we use a negative feedback rather than a single gain to reduce the error?
I'm studying signal analysis, and we reached a topic of correcting and enhancing a system with the following transfer function :
$$
\frac{Y(s)}{U(s)} = \frac{2}{s^2 + 5s + 6}
$$
with \$U(s) = ...
-1
votes
1answer
41 views
Digital Signal processing-Sampled period
Please can you help me with exam test preparation. I have take the below past year exam paper.
I want to know if I am on the correct track and my answers are correct.
x(t) = cos(50.pi.t + 30) ...
1
vote
1answer
86 views
What is the FM threshold effect?
I came across a picture ( shown below ) comparing the SNRs of FM and AM. There was also some explanation of the FM threshold effect and how the threshold effect is the reason as to why the FM graphs ...
0
votes
1answer
58 views
Order analysis, need help
Hi fellow electronics enthusiasts.
I'm currently working on vibration detection machine used to detect unbalance from a rotating shaft, rotating from 300-2500 Hz. I have both the tacho signal ( 1 PPR ...
0
votes
2answers
130 views
Fourier transform of \$x(t) =t^2e^{-|t|}\$
I have to find the Fourier transform of this function.
(- sign exists BEFORE modulus). I thought of using this standard result.
If I split this fourier transform into this will it be correct ...
1
vote
0answers
53 views
Problem with biased circuit for oxygen sensor (SGX EC410)
I have designed a circuit for an SGX EC410 oxygen sensor by using these application note -PAGE 4, FIGURE 4 - ...
0
votes
1answer
74 views
How to design the frequency response of an analog filter when I get the transfer function?
I am not trying to design a filter. I just want to understand the theory of laplace transform and s-domain.I read an example from the book The Scientist and Engineer's Guide to Digital Signal ...
1
vote
3answers
79 views
How to record input from multiple microphones so there is no latency between microphones due to writing to memory
I am going to be doing some beam forming. I understand the concept and plan to record all the data then analyze the signals from multiple microphones to figure out locations of some noises (there will ...
2
votes
1answer
52 views
When to process beam forming algorithms?
I am building a system that uses beam forming to locate noises at different spots. All of the spots will be in front of the microphones (180 degree range of spots).
My first question is if the beam ...
1
vote
1answer
44 views
Difference is Bluetooth Smart and Bluetooth audio
My name is Raveen Baloo. I have been doing a lot of research on the types of Bluetooth module. For my project, i do need a bluetooth which will be able to have simple communication with a mobile app, ...
1
vote
1answer
56 views
band pass filter on solar cell to detect laser
my target is detecting a laser generated with 1k frequency using a solar cell, i'm using this idea which is using a band pass filter on the solar cell to block the dc sun light and let me detect the ...
0
votes
0answers
69 views
How to determine continuous-time delta-sigma loop filter coefficients?
I want to design a 3rd order CT delta-sigma CIFB modulator having determined a noise transfer function, but I can't grasp details how to do this.
I am using the popular Delta-Sigma Toolbox by R. ...
-1
votes
3answers
78 views
Is there a Binary Frequency Shift Keying (BFSK) with only one sine tone?
I mean a modulation technique where a binary one is represented by a sine wave with some frequency F and a binary zero is represented by an absence of any signal, or vice versa. Does it have a "right ...
0
votes
1answer
53 views
How can I derive a voltage equivalent without affecting the output?
In the above schematics, I want to make the equivalent of the circuit on the left side. What I mean is I want to derive V2 from V1 and get rid of using two supplies. I want to derive V2 from V1 by ...
-2
votes
1answer
54 views
what is the difference between positive and negative feedback in an opamp? which is used when? [closed]
how is it said that opamp with negative feedback operates in linear region?and positive feedback is unstable? then how do we use positive feedback in schmitt trigger?
0
votes
3answers
169 views
why is noise always a high frequency signal ? what then is frequency of a noise?
while designing signal conditioning circuits for sensors , we design low pass filters to remove high frequency noise. why can't noise be a low frequency signal or what will its frequency be ?
0
votes
1answer
30 views
(VCA - VGA) Design of an amplifier controlled by a ramp
I would like to design a circuit with an AOP which will have a variable gain controlled by a tension (a ramp). Could you help me and explain me the circuit please?
Thank you,
Farad
3
votes
3answers
103 views
Converting an arbitrary pulse to logic level
Background:
I'm trying to measure the time interval between (4) different pulses with a baseline of ~2V and rougly 1.6V p-p . Currently I'm using the ADC on an STM32 to sample the four channels.
...
1
vote
2answers
116 views
Envelope detector
I would like to have the envelope from a signal using a simple circuit composed of a diode and a low pass filter.
I know :
*Tam > t >> Tcarrier
*The diode must be a germanium diode because of the ...
0
votes
2answers
97 views
Difference between TGC (Time Gain Compensation) and AGC (Automatic Gain Control)
I'm a french student who work on a portable echograph for the "echopen" association : http://echopen.org/index.php?title=Main_Page
I'm working on the analog part which is composed of theses parts:
* ...
1
vote
0answers
26 views
Single Sideband LSB Demodulation
The problem is how the phase φ effects the outcome when the input(message signal) is the DSB-SC LSB.
It's :
message: \$m(t)=A_{m}cos(ω_{m}t)\$
carrier: \$c(t)=A_{c}cos(w_{c}t)\$
I found that the LSB ...
0
votes
1answer
57 views
Sampling frequency and FFT
I have tried this example code for sampling and FFT in MATLAB, but I have noticed that when the signal frequency becomes closer to nyquist frequency , some errors ( small frequency components near the ...
1
vote
2answers
92 views
how can i filter this spikes on FFT?
i am working on very low amplitude signals and sensors. I have recorded one hour data. And i am looking its FFT graph. You can see FFT image. My question is that, what can cause the spikes in FFT ...
0
votes
1answer
75 views
Extracting amplitude of signal from FFT plot
I am busy with to extract peak amplitude of a noisy 1 hz signal. As you can see the image, the signal is very noisy. I need its average amplitude peak value. However i can easily and perfectly find ...
1
vote
1answer
49 views
Non-unique Sample Rate
Given
$$x[n] = \cos\left(\frac{\pi}{3} n\right)$$
That was obtained by sampling
$$x_c(t) = \cos(4000\pi t)$$
At \$T\$ samples per second, find \$T\$. Is \$T\$ unique? Why or why not?
$$x[n] = ...
0
votes
1answer
42 views
Synchronous Serial over Internet
I have a portable diagnostics tool which communicates with an electronic appliance using which I believe is Synchronous Serial Interface (SSI).
I'm looking for a way that I can extend the range of ...
1
vote
1answer
69 views
From DTFT to DFT, why do we take N samples in frequency domain
In this post:
Why does frequency equal k/K where k=0,…, K-1 in Discrete Fourier Transform?
And I have read several books, the authors take N samples with DTFT to get DFT. Why N?
I think N is simply ...
0
votes
1answer
78 views
Are TI TMS320C6x and TI TMS320C2x compatible?
I never learnt assembly language programming. But, I know C and C++.
I need to learn C2000 Piccolo programming. I found no book on C2000, there are only manuals from TI website.
But, suddenly, I ...
1
vote
0answers
43 views
How can shot noise be dependent on dc current, not instantaneous average current?
After looking at the formula of shot noise and its derivation, I thought current in shot noise refer to instantaneous average current, not dc current. By instantaneous average current, I mean current ...
0
votes
1answer
32 views
How many ePWM instances are there in a TMS320C28x Piccolo DSP chip?
In this reference manual, it is written that:
[Page 11] 1 Introduction
......
Cross coupling or sharing of resources has been avoided; instead, the ePWM is built up from smaller single ...
0
votes
1answer
34 views
implications of difference between RMS and mean in rectified and non rectified graphs
I have a project relating to EMG signals and i did a full wave rectification to zero for the graphs before calculating mean and RMS of the graph. My question is, would it make more sense to find the ...
2
votes
1answer
51 views
Why is it difficult to develop wide-bandwidth analog-to-digital converters?
How is bandwidth of analog-to-digital converters constrained? In particular, why would sample-and-hold subcircuitry not be able to perform high-speed switching?
1
vote
1answer
280 views
Does frequency need to be an integer in order for a signal to be periodic?
Please help me understand periodicity. Why can \$T=\frac{1}{3}\$ be periodic but \$T=\frac{1}{\sqrt{3}}\$ be aperiodic?
For example:
$$\cos(2\pi\times 3\times n) \Rightarrow \mathrm{periodic}$$
...
1
vote
0answers
81 views
How to implement autocorrelation (matched filter) in hardware?
I have an understanding of how to implement autocorrelation via the means of software, but after an extensive search on the internet I could not find how to implement it with hardware/electronics. In ...
1
vote
1answer
47 views
Find Power Spectral Density of given signal
I am given a question with very brief notes to study from. The question is this:
Now I was wondering, are the following part of the notes relevant at all:
Is this the appropriate method to solve ...
