Questions tagged [digital-modulation]
Digital modulation is encoding a data signal onto a carrier wave for transmission. There are several different methodologies for digital modultion.
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Distinguishing light sources with STM32 ADC and fast fourier transform
I want to identify if there are other light sources present at the same time as a 5 kHz 50% duty cycle PWM LED is on (this is arbitrary and it can be modulated at a different frequency). I have an ...
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How does this delta-sigma modulator work without a clock signal
I've been recently studying about delta-sigma modulators trying to understand a schematic of an amplifier, while I came across this simulation of 2nd order D-S modulator, by far this is what I was ...
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How do we calculate the amplitude levels in QAM modulation technique
so I came across M-ary Modulation technique in my ADC subject. While I understood the basic principle behind it, I still cant get my head around the amplitude levels taken . Like lets say i am using ...
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Why do we need to transmit in a cable with a digital modulation? Can't we just put high voltage for 1 and no voltage for 0? [closed]
We know that we can't transmit a square wave pulse via EM and we need to convert it to an analog signal via some modulation.
But why can't we just put high voltage in the cable to represent bit 1 and ...
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Phase modulation for binary data - higher frequency harmonics?
I've recently learned about PSK and QAM. I first came across it in this youtube video (timestamped), and my understanding for how it works has remained the same as what is shown in that video. (I also ...
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Frequency meter (counter)
I am currently working on designing a circuit that should be able to measure the frequency of an input signal by giving off a value directly proportional to the frequency at the input.
The circuit ...
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Measuring Doppler and Doppler rate at a receiver
I am simulating receiving a digital signal, QAM modulation, raised cosine pulses... from a satellite to a receiver on the ground. I wanted to honestly simulate measuring the Doppler and Doppler rate ...
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Regular DACs versus audio DACs
Context
In trying to make modular linear power supply with digital control, I figured I'd need a DAC to output the correct voltages into the feedback circuitry (two - one for voltage and one for max ...
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How to convert low voltage digital signal (0-3.3V) to high power current signal 15-40W ranging from 1kHz to 1MHz?
I need to convert a digital signal generated from a microcontroller GPIO (0-3.3V) to a high-power (15-40W) current signal to drive an LED chip for illuminance, where the signal frequency can range ...
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VHDL: Testbench for ASK modulator
I've been trying to learn VHDL recently and came across the following tutorial for an ASK modulator: https://surf-vhdl.com/implement-digital-ask-modulator-vhdl/
I tried writing a testbench for this ...
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Amplitude shift keying using NMOS cascode transistor configuration
. I am using 50 MHz as a carrier signal and a pulse signal as the data signal. Unfortunately, I could not get my desired modulated ASK signal. I am using ADS software. Kindly guide me on how to do it. ...
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Isolators and Level shifters - default to logic 1
I've been making my first boards to do some testing in power electronics. I'm testing unpowered circuits, and there's something that baffles me.
I'm testing if pulses appear correctly on gate drives ...
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Constellation diagram of an 8-PSK modulator with \$\cos(\omega _ct)\$ as reference oscillator [duplicate]
For the figure and problem below, is my 000 input plotted correctly and has the correct phase angle in my constellation diagram?
The cos(ωct) is located on the positive x-axis since according to my ...
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Constellation diagram of an 8 PSK with a \$\cos(\omega _ct)\$ reference oscillator
Please help me with this problem in Tomasi's book for digital modulation. After getting the summer output, I got confused about what to draw in the constellation diagram.
According to my prof, since ...
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Why does norm of the PAM bandpass signal give energy of the pulse over two?
I would like to understand why \$\int_{-\infty}^{+\infty}g^2(t)cos^2(2\pi f_c t)dt = \mathcal{E}_g/2\$
\$g(t)\$ is a pulse of duration T.
the background is:
reading the book "Digital ...
