Stack Overflow
Stack Overflow

Questions tagged [modulation]

Anything related to *signal modulation*, i.e. the process of encoding the information provided by some source into the variations of some property (e.g. amplitude, frequency, phase, polarization, etc.) of a carrier signal suitable to be transmitted over a communication channel.

Anything related to signal modulation, i.e. the process of encoding the information provided by some source into the variations of some property (e.g. amplitude, frequency, phase, polarization, etc.) of a carrier signal suitable to be transmitted over a communication channel.

See Wikipedia page on signal modulation.

120 questions
1
vote
0 answers

android PPM decoder audio library

I need to implement audio PPM (Pulse Position Modulation) on android Reference: http://en.wikipedia.org/wiki/Pulse-position_modulation I want to receive PPM using the audio microphone input of the smartphone. The radios for radiocontrols, drones,…
Gaucho
  • 1,328
  • 1
  • 17
  • 32
1
vote
2 answers

How to create diagonal stripe patterns and checkerboard patterns?

Based on this question, I can confirm that horizontal patterns can be imposed onto a matrix (which in this case is an image), by multiplying it with a modulation signal created with this: vModulationSignal = 1 + (0.5 * cos(2 * pi * (signalFreq /…
SDG
  • 2,260
  • 8
  • 35
  • 77
1
vote
1 answer

How to plot colorful histogram type constellation diagram in Matlab

I would like to plot constellation diagram similar to the figure below. . My approach is something like this clc; clear all; close all; N=30000; M=16; Sr=randint(N,1,[0,(M-1)]); …
salmannsu
  • 193
  • 1
  • 9
1
vote
1 answer

GNU Radio - PSK Mod block - unexpected constellation diagram

I am simulating a QPSK modulation in GNU radio. Here is the . The source is a binary stream coming from the Random Source block. There are 4 PSK Mod blocks configured identically (4 constellation points - a QPSK modulation, Grey coding and…
Mirta Iva
  • 13
  • 1
  • 4
1
vote
1 answer

Frequency modulation function in Matlab

I'm attempting this matlab code but I keep getting an error. Any hints? %Frequency Demodulation f_fmCarrier=1000; %frequency of FM carrier signal f_sampling=f_fmCarrier*2; %frequency of…
Josh
  • 11
  • 2
1
vote
1 answer

MATLAB how to map the received point to one of the constellation points

I'm trying to design a new modulator / demodulator. I've designed the constellation set and mapped them to bits using a gray mapping, Added some AWGN noise to the signal and now I'm trying to demodulate. Lets say I have the following points in my…
hussein hammoud
  • 385
  • 1
  • 7
  • 20
1
vote
1 answer

android PPM encoder audio library

I need to implement audio PPM (Pulse Position Modulation) on android Reference: http://en.wikipedia.org/wiki/Pulse-position_modulation I want to output PPM from the audio output of the smartphone. The final scope is to create a joystick for…
Gaucho
  • 1,328
  • 1
  • 17
  • 32
1
vote
1 answer

Transmission of the image using BPSK

Input image needs to be modulated and transmitted and finally detected using BPSK. M = 2; %Modulation order 2 for BPSK randn('state',200); % initializing the randn() function imdata = imread('lenna.pgm'); bdata = de2bi(imdata); sizec =…
ypbear
  • 115
  • 1
  • 5
1
vote
2 answers

BER result for QAM modulation Matlab

I'm trying to put a binary vector through a 16-QAM modulator, AWGN channel, demodulator and measure the BER in the end. for some reason it keeps giving me BER=0, even after if I change the length of the vector. (I'm supposed to do it with a Rayleigh…
Jake
  • 15
  • 4
1
vote
2 answers

Converting 8 bits to a byte for amplitude modulation in Java

So I am writing a program in Java that does amplitude demodulation. I am reading in a sine wave value by value and determining whether I have a '1' or a '0'. For now I am saving them as chars, but am open to suggestions. I know the number of samples…
user3333414
  • 125
  • 1
  • 2
  • 7
1
vote
0 answers

Stereo FM modulation in Matlab

My question might be simple, but I am stuck in here for quite a while. I am trying to simulate a stereo FM complex baseband signal in Matlab. I am using "Analysis and Emulation of FM Radio Signals for Passive Radar" paper from an Italian group as my…
Tunç Arslan
  • 133
  • 1
  • 12
1
vote
1 answer

How to increase bitrate of file transmission over the sound card?

I need to transfer files using only the sound card. my algorithm so far is based on amplitude shift keying (ASK). Transmitter: The program writes to a WAV file the modulated data. Simply write "noise" (create wave) when the bit is 1, and write…
flyman
  • 210
  • 4
  • 15
1
vote
1 answer

BER graph MATLAB calibration

I'm doing a 16QAM system (transmitter, channel and receiver), and BER and PER curves of the results. However, I'm having some problems with noise at the receiver. I'm running the system inside two loops: for all the Eb/No values and for all the…
Natiya
  • 463
  • 2
  • 9
  • 25
1
vote
1 answer

Modulating a MatLab signal

I'm trying to modulate a signal in MatLab by multiplying some signal with a carrier signal. The carrier signal is cos(2*pi*fc*t) and this is my code so far for t = 1:length(input); m(t) = (Ac + input(t)).*cos(2*pi.*fc.*t); end xam =…
user2929779
  • 359
  • 5
  • 13
0
votes
0 answers

WebSDR and continuous wave (CW) demodulation of DCF77 signal

I am trying to receive DCF77 signal via WebSDR. When I set CW demodulation I hear the sound even if I select the band with 0 width. I am relatively new to the radio. The question is why I do I hear the sound? I know that CW modulation is used for…
Art Spasky
  • 1,635
  • 2
  • 17
  • 30
1 2 3
4
5 6 7 8