Questions tagged [oscillator]
The oscillator tag has no usage guidance.
41
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Why is my FM synth getting out of phase?
I'm trying to create a software FM synth following the formula for frequency modulation:
$$
y(t) = A \cdot f_c(t + I \cdot f_m(t))
$$
Where $A$ is amplitude, $f_c$ the carrier function, $f_m$ is the ...
- 101
0
votes
1
answer
47
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Wavelet signal analysis approach for multi-mode, noisy signal
I have a signal that I am trying to analyze via Matlab's CWT functions. The signal has two distinct oscillating components and I would like to extract the decay factor from each of them. Here is what ...
1
vote
0
answers
30
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Sampling Oscillators for Lookup Table
I have couple of analog synthesizers and I want to turn their oscillators into code. I've been reading about how to do it for a while and making a lookup table seems just right for me. I've been ...
2
votes
1
answer
165
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Why does my PLL simulation oscillate after locking?
I'm working on a crude circuit simulator with the goal of implementing PAL encoding and decoding, so that I can experiment with generating images that look like video transmissions.
In the simulation ...
- 121
-1
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1
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242
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Phase Noise and Multi-carrier Frequency conversion
I have a oscillator with a phase noise mask that was represented in dBc at specific offsets from a carrier.
Two options for a multicarrier signal going into a converter, apply the phase noise mask (...
- 97
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1
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103
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How to choose frequency of local oscillator for heterodyne principal
I am trying to implement the heterodyne principle in order to make an AM signal demodulator that can demodulate signals on a set bandwidth(550 - 1720kHz). Is there a formula or some other method of ...
- 13
1
vote
1
answer
499
views
Adding phase noise to a signal results in amplitude variation on a constellation - whats the mistake? *plots inside*
I am attempting to add phase noise to a modulated signal.
I am doing this by taking a phase noise mask (single sided 0 Hz to 1
MHz), which shows dBc values away from central value or reference
value. ...
- 97
3
votes
1
answer
916
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Allan Variance vs Autocorrelation - Advantages
I am currently studying oscillator stability and have come across the Allan variance. I gather that it was developed as an alternative to the standard variance as it doesn't necessarily converge for ...
- 53
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1
answer
147
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Pointers for digital FM synthesis
I am working on a digital synthesis project, in python and c currently. I have made a Sine and Saw wave generator and have now been working on FM between the two wave types. I have successfully made ...
- 1
7
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1
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464
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How to calculate critical damping of a system with two springs and a damper (or two springs and two dampers)?
Background
For a simple system where you have a mass attached to a spring and damper in parallel:
We can calculate the critical damping from the equation of motion:
$mx_{tt} + cx_t + kx = 0$
$ms^2 + ...
- 447
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1
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178
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What equation predicts the amplitudes of harmonics from a square/triangle/sawtooth/pulse oscillator?
I have seen pictures like this which depict the shapes of amplitudes from the various common types of audio oscillators:
Similar pictures of spectra are shown here.
I am attempting recreating these ...
- 447
2
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0
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460
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PolyBLEP: solving two part residual
The Polynomial Bandlimited Step (PolyBLEP) methodology involves approximating the sinc() function with a polynomial. The most basic polynomial to choose is a uni-polar triangular pulse as it is the ...
- 867
1
vote
2
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108
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Output of marginally stable systems
In' b.p lathi's book of systems and signal it is written that
"marginally stable systems have one important application in the oscillator, which is a system that generates a signal on its own ...
- 269
0
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1
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746
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Detect when signal starts oscillating
I have a signal which consists of oscillations riding on square waves as shown in the image below. I wish to detect the time at which oscillatory events occur (as shown by the red star).
Each square ...
1
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0
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36
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how to reduce signal noises
I am trying generate guided waves on simple metallic plate through piezo-ceramic material, I place two piezo on the surface of the plate at the different location and through Arbitrary pulse generator,...
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1
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177
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NCO loses lock after a while for certain values of alpha
EDIT: So the transfer function for my system is
$$ F_{nco}(z)=\beta E(z)/(z-1)$$
$$ z\Theta_{nco} (z)=\Theta_{nco} (z)+\alpha E(z)+\beta E(z)/(z-1)$$
So I would like to obtain $\Theta_{nco} (z) / \...
- 223
1
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1
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169
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Denoising Oscilloscope data the right way [python3]
I need to plot large oscilloscope data sets. They are too large (100 million Values) to plot all of them in a for loop. If I try to do that it results in a ...
2
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1
answer
1k
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polyBLAMP anti-aliasing in C++
How should 4 point polyBLAMP work. It does not really seem to dampen aliasing.
I have an floating point digital audio oscillator that makes a +1.0f jump at the end of every period.
My question is, ...
- 149
1
vote
3
answers
4k
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How to recover frequency and damping coefficient from superposition of damped oscillators?
I have a signal which is (more or less) the superposition of multiple damped oscillators. There are relatively few oscillators involved, 2-3 would account for most of the signal. They have periods ...
- 230
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1
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74
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Is there any special when all Fourier components have the same angle?
When a square wave doesn't jump, its oscillators aren't aligned:
But if they are in sync, the wave will jump to its extrema:
However this is just an example of square waves. The tool Understanding ...
- 131
2
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4
answers
114
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What is the moment when all oscillators aligned to make a jump called?
Say we have a square wave and its Fourier series. When the wave doesn't jump, its oscillators aren't aligned:
But if they are aligned, the wave will jump:
What is this moment called? They might not ...
- 131
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3
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556
views
How do I stabilize my oscillating system?
I have two scalars $x$ and $y$ that vary with time $t$ such that
\begin{align}
\frac{dx}{dt} &= ay + b + dx\\
\frac{dy}{dt} &= cx
\end{align}
but $a, b, c$ are unknown.
If $d$ is too small, ...
- 111
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1
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120
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DC bias of waveform
I have a waveform which is built from a math function. I want to repeat it to make a oscillator.
Now to offset it to remove dc bias, do I just make total area equal zero?
- 149
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0
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97
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Bandwidth enhanced sinusoidal model with oscillators banks
i am currently implementing the bandwidth enhanced sinusoidal model for an additive synthesizer, this model allow to accurately produce noisy sounds by adding a noise component to each sinusoids.
But ...
- 113
2
votes
1
answer
1k
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How to account for multiple signals in the input to a Kalman filter
I am interested in using a Kalman filter to track an oscillating signal due to a physical oscillator in a signal which contains the signal from multiple such oscillators oscillating at different ...
0
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1
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210
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How to implement a digital sawtooth oscillator? [closed]
In reference to this topic: How to implement a digital oscillator?, I would like to know how can I implement a solution similar to the one in the topic on a Sawtooth oscillator.
-1
votes
2
answers
380
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How to look at Rubidium frequency standard using the oscilloscope?
This question is about the checking hardware, please help if someone who has done it before.
I have the Rubidium frequency standard: http://www.thinksrs.com/products/PRS10.htm
and the Oscilloscope: ...
3
votes
1
answer
5k
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Numerically Controlled Oscillator (NCO) for phasor implementation?
If I want to simulate a digital oscillator (or phasor) to modulate an arbitrarily length signal:
$$y(t) = \cos(2\pi f_ct)\quad\text{where}\quad t = \frac{n}{f_s}\quad\text{for sample}\quad n$$
What ...
- 521
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1
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433
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Resonance circuit peak filter with unity stopband in MATLAB
I would like to insert a filter with an resonant filter characteristic of a realistic mechanic oscillator. I need to apply it in the time domain, e.g. with a function such as ...
- 13
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1
answer
2k
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Generate loopable sine wave cycle for given frequencies
I am somewhat new to DSP so bare with me. I am working on a simple wavetable oscillator. What I am trying to do is generate one cycle of a wave form for each note (frequency) and store it in an array ...
- 51
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1
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237
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Freeform band-limited waveforms
I'm ready to dip my toes in the scary waters of non-aliasing waveforms and wavetables. Ideally, what I'd like to do is create a (naive) wavetable/waveform in memory and subsequently generate band-...
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280
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Why does signaling overhead for time synchronization scale up with the number of transmitter nodes in a multiple access system?
I was recently reading about random multiple access methods without time synchronisation (of the pure Aloha type). In this paper it is stated that,
The need for transmitter synchronization is a ...
- 378
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2
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770
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Aliasing Square Wave
I'm having a really weird issue with generating waveforms from frequencies C1 to C8.
When I generate sine waves, everything sounds good; no problems whatsoever. However, when I generate a square ...
- 209
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3
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3k
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Band limited wavetables
I am a bit confused with the concept of band limited wavetables and the methods such as BLET, BLIP, MinBLEP, polyBLEP etc.
As far as I understand certain waveforms contain infinite harmonics, which ...
- 669
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701
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how to correct minBLEP sawtooth oscillator DC bias
In my implementation of minBLEP, overlapping minBLEPs result in a DC bias as the frequency increases. This is because each minBLEP correction (i.e. the minBLEP minus the aliased step) has a DC bias.
...
- 131
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440
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efficient triangle to sine morphing?
I'm coding a synthesis external for MaxMSP in C.
It's based on Peter Blasser's bounds and bounce concept ( http://petermopar.blogspot.co.uk/2014_04_01_archive.html )- basically triangle waves with ...
- 103
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1
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1k
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Best way to morph between waveforms
I am making an low-frequency oscillator (LFO) that should be able to output different kinds of waveforms.
If I, say, want to be able to create a smooth transition from a sine wave to a square wave, ...
3
votes
2
answers
2k
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IIR oscillator produces stable output in MATLAB, unstable on chip, how do I tune it?
I'm trying to make an oscillator using IIR filter and I'm having problems tuning it so that it's stable on the platform I'm using (ARM Cortex M4F and CMSIS DSPLib's arm_biquad_cascade_df1_f32). Note ...
- 206
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2
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1k
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Band Limited Table Look Up Oscillator C++
I would like to create a Band Limited Table Lookup Oscillator that functions much like the sin() function in C++ works where i would inout a phase value and receive ...
- 221
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votes
3
answers
285
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Is sinusoids the nature's default signals?
I know the basic working principle of sinusoidal oscillators. But I have a doubt on this matter when I came across Gram-Schmidt orthogonalization procedure. I have read that the source for sinusoid ...
- 339
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3
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11k
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How to implement a digital oscillator?
I have a floating-point digital signal processing system that operates at a fixed sample rate of $f_s = 32768$ samples per second implemented using an x86-64 processor. Assuming that the DSP system ...
- 3,773