Questions tagged [demodulation]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0
votes
1answer
71 views

FM demodulator LTspice

I am now designing an FM demodulator circuit. And the first step is turning FM into AM, so I could use envelope detector afterwards. Modulator circuit is designed using Colpitts topology. So frequency ...
1
vote
2answers
66 views

How can picked up FM noise be demodulated?

I have a set of cheap computer speakers, which happens to use a TDA2822M. Its circuit is almost identical to the example circuit from TDA2822M's datasheet. It's USB powered and has no shielding. I ...
0
votes
1answer
25 views

What does 'succeeds' and 'precedes' symbols mean in design of a peak detector circuit?

I am looking into the design of a peak detector circuit for demodulating an amplitude modulated wave. The circuit is a diode 'detector' connected to a low-pass RC filter. I have been given the ...
0
votes
1answer
34 views

Coherent and non-coherent detection

Let's say I am simulating something as simple as BFSK. It has two symbols, one entirely on the real plane, and one entirely on the complex plane for representing let's say zero. That is how the ...
0
votes
0answers
20 views

Is \$ H\left\{x_h(t)\right\} = H\left\{x\left(t-\frac{\pi}{2w_c}\right)\right\} \$ where \$H\$ is Hilbert transform

Accordind to my understanding of the following: $$H\left\{X(f)\right\} = -j\;sgn(f)\; X(f) \qquad(1)$$ my work so far: since \$ x_h(t) = x\left(t-\frac{\pi}{2w_c}\right)\$, Their Hilbert ...
2
votes
1answer
54 views

Collpits FM Receiver

I saw this simple schematic for an FM receiver: https://www.mikroe.com/ebooks/radio-receivers-from-crystal-set-to-stereo/the-simplest-fm-receiver Moreover, I saw some videos online where people have ...
2
votes
1answer
39 views

Filtering a demodulated signal

I've created a simulation on Matlab of amplitude modulation. After demodulating the signal I need to add a low-pass filter to remove the high frequency components. I'm confused as to why this is? I ...
0
votes
0answers
52 views

FM Detector Using LM565

I am currently working on a power line communication project. I want to send an audio signal through the power line. In order to do that I would need to modulate my signal and in this project I am ...
0
votes
2answers
38 views

How is dc restorer circuit used for PWM demodulation/detection?

In the Microelectronics Circuits textbook by Sedra & Smith, it is said that: As an application, consider a pulse signal being transmitted through a capacitively coupled or ac-coupled system. ...
0
votes
0answers
50 views

Demodulation of DSB-SC modulated signal

I have a DSB-SC modulated signal as follows: \$s_{in}[n] = SUM[n] \times cos(\frac{2\pi f_{SUM}}{f_{sin}}n) + DIFF[n] \times cos(\frac{2\pi f_{DIFF}}{f_{sin}}n)\$ where SUM[n] and DIFF[n] are the ...
0
votes
1answer
48 views

Synchronous detector question [closed]

The author explains it as a synchronous demodulator. Here we can see that two multipliers which multiply both the inverted and non inverted signals. Can I do the same with only one switch for non ...
0
votes
0answers
32 views

peak detector simulation

I am simulating an AM demodulator using the peak detector in Orcad softwere, but I find a convergence problem, regardless of the simulation time I use. Can you help me to resolve this problem? For ...
0
votes
1answer
29 views

What does division order mean in Rayleigh Fading?

So I'm just beginning to understand how Rayleigh Fading works and I'm trying to model some different modulation schemes with Rayleigh fading channels. I'm doing this on MATLAB where one of the ...
0
votes
0answers
16 views

LA72910V Demodulator and Modulator Noise Problem

The project includes a DC power supply that supplies two cards and provides a network. The video signal is modulated through LA72910V whether a card is demodulated in the other card. There is no ...
1
vote
1answer
104 views

How does this demodulator exactly work?

I have the following circuit which is an AM demodulator (I think). RF input is between the diodes left: Plotting the bode plots for the negative and positive input of the comparator, I get a lousy ...
0
votes
0answers
31 views

how to increase the sensitivity of a home-built locked in amplifier?

I am building a locked in amplifier from scratch for an optoelectronic device using a couple of boards in conjunction with the STEM Redpitaya. The System configuration is as follows: Signal(coming ...
2
votes
1answer
753 views

Can someone explain how this Ratio detector circuit works?

I understand how a Foster Seeley discriminator works, but in this Ratio detector, which is a modified version of the former, I don't understand the purpose of having three transformer windings, or ...
1
vote
1answer
93 views

Envelope detector for AM signals

How or what are the constraints for deciding factors of envelope detector for AM As far as I know that charging time of capacitor should be below 20T where T is periodic time of carrier and ...
1
vote
0answers
67 views

Foster - Seeley FM Demodulator Explanation

Consider this Foster Seeley Demodulator If I have correctly understood, its basic working principle is the fact that at the secondary coils (L2) of the Balun there will be two signals equal and ...
1
vote
1answer
54 views

What is the minimum sampling rate for QPSK or what is the bandwidth of QPSK signal?

Consider we have created a QPSK signal with a carrier frequency 100kHz. Before applying matched filter or demodulation we need to take sampls from the received signal. So what is the minimum sampling ...
0
votes
1answer
31 views

What is a reference oscillator which is used in Costas receiver?

A Costas receiver has a voltage-controlled oscillator, which is sometimes referred to as reference oscillator. What is the input and output of this reference oscillator?
2
votes
1answer
239 views

FSK demodulation with LM565

On the Internet I found FSK demodulation connection diagram with LM565 . And I'm trying to connect up it in Qucs. At the output of the whole schema I get unclear result. In my previous topic we were ...
-2
votes
1answer
156 views

FM Demodulation

I'm using a demodulation fm circuit in multisim. it takes 1 minute on the oscilloscope to complete a full waveform, and every waveform the amplitude is decreasing. I want to know why is the amplitude ...
1
vote
0answers
62 views

How does a rectifier demodulate radio information and why does its capacitance matter?

I read in a forum “A point contact diode like OA79 should be used for the demodulation of AM. This diode is a signal diode and is having a low junction capacitance because of its special construction. ...
1
vote
1answer
311 views

Synchronous demodulation with single supply op-amps

I am looking at the following article from Analog Devices: Use Synchronous Detection to Make Precision, Low Level Measurements, and I'm wondering if there is a way to build the following demodulator ...
0
votes
2answers
33 views

Proper term for waveform correction — demodulation or undistortion

I have a measured a periodic signal waveform \$v(t)\$ that can be modeled as: \$v(t) = f(\phi) A \sin(2\pi ft + \psi)\$ where \$A\$ is a constant amplitude, \$f\$ is signal frequency, \$t\$ is time ...
1
vote
0answers
69 views

ASK demodulator not working as expected

I have implemented an ASK modulator and demodulator pair. The modulator works fine, but the demodulator is giving a vague output. Below is the image of the whole circuit and the simulation output. ...
0
votes
1answer
24 views

prevent receiver components from interfering with output of modulator

I am working on an ASK modulator and de-modulator. The modulator works fine (thanks to great folks at SE). However when I try to pass the modulator output to the input terminal of the receiver, the ...
1
vote
0answers
39 views

PLL with two input frequency within lock range for FM demodulation

I have current output from a photodiode which I believe containing at least two distinct frequencies that is not too far apart from the lock range of a PLL which taking this current as the input ...
1
vote
0answers
206 views

Demodulation of a 38 kHz IR PWM signal

I want to learn how to demodulate a 38 kHz IR PWM signal.(Such as that transmitted by a TV Remote Control) I know it can be demodulated easily using a TSOP1738 IR receiver. I realize that the ...
1
vote
1answer
48 views

Source generator for Satellite Tuner input

I need to design a source generator for a TV factory. They want to automatize the functional tests by applying a test module to the TV's at the end of the production line. All the peripherals of the ...
2
votes
1answer
268 views

In this Foster Seeley discriminator, what is the purpose of capacitor C3?

I understand the whole circuit, except for the use of capacitor 3. What's its purpose in here?
2
votes
0answers
86 views

High SNR FM demodulation

So I need to demodulate the FM signal from a sensor with highest SNR possible, at least 70-75 dB. IF is 10.7 MHz, max. deviation is 200 kHz but I can change those values if needed. Baseband signal ...
0
votes
0answers
259 views

Keyfob decode using GNU Radio Companion

Found this project to decode Hella Keyfobs https://github.com/bastibl/gr-keyfob Try to decode mine, but somehow the signal is way different from the one from the above Repo. From the repo: Mine: ...
0
votes
1answer
401 views

Can a speaker be driven by a DC signal?

I’ve always been under the impression that speakers require an AC signal. The reason being that positive and negative current are required for the electromagnet to properly vibrate the diaphragm. ...
1
vote
2answers
64 views

Geometric representation of GMSK signal

Can anyone provide me the geometric representation of GMSK signal? Also, am I correct in saying that bit energy of GMSK is same as its symbol energy since MSK is a binary modulation scheme with only ...
1
vote
4answers
268 views

Is there a way to extract out just the Carrier signal from an AM signal?

I have a AM signal with 13.56MHz carrier and 125KHz data signal. I was wondering if there is a way to extract out just the pure carrier signal out of this AM signal. I was thinking about passing it ...
1
vote
0answers
119 views

Phase Locked Loop Gain Design- FM Demodulation

Say I am trying to demodulate a message up to 25kHz in frequency, with a peak frequency deviation of 75kHz and a carrier of 1MHz, implying a 200kHz bandwidth using carsons rule. Would I design the ...
0
votes
3answers
228 views

High frequency AM demodulation

I'm building an light communication device(pretty much lifi) using AM and am mostly done with every part except for demodulating the signal. The signal looks like with a 1.8432MHz carrier wave(serial ...
2
votes
2answers
367 views

Select Phase Detector Cutoff Frequency? Phase Locked Loop FM Demodulation

I'm studying a Phase Locked Loop used for FM demodulation, obviously a phase detector is used in the system. A basic implementation of a phase detector is a multiplier followed by a lowpass filter. I ...
2
votes
0answers
437 views

Matlab Phase Locked Loop Design : FM Demodulation

EDIT: It seems I've asked too much at once here. I'll do some more studying and come back if I have more specific questions. I'm trying to design an analog phase locked loop in Matlab. I've read ...
1
vote
1answer
920 views

Choosing a RF Detector Circuit for my Sweep Generator

My newly acquired sweep generator (wobbulator) doesn't have an inbuilt RF detector circuit unlike some others (some Wavetek models). So, I decided to build one. I was quite surprised at how many ...
2
votes
2answers
175 views

What kind of component was used in this demodulation circuit?

I was trying to gather components as well as some desoldering experience from an old television tuner when I found those little fellows: They were sitting next to an IC with the Code TDA 6160-2X. ...
0
votes
1answer
498 views

Best mixer for quadrature FM demodulator

I need to demodulate an FM signal and I want to use a quadrature demodulator for this. The signal is 16±0.15 MHz, 3.3V output from CMOS oscillator. I know that Gilbert cell mixers are most commonly ...
1
vote
1answer
134 views

Demodulator with Schottky diodes

I was wondering how this demodulator works. The input voltage is on the left at C2 and the output voltage is on the right before C3. What is clear: C2 filters out low frequencies at the input, C3 ...
1
vote
1answer
73 views

Modulated IR for optical transmission of encoder data (TSOP 4840)

Some background: I am a mechatronics engineer and I have just recently started my first job out of university as an electrical engineer. I feel a little out of my depth but I wasn't going to turn the ...
0
votes
1answer
1k views

Interpreting IQ Data (as hex) from an RTL-SDR/Hack-RF

I am wondering if someone can shed some light on how to meaningfully interpret I/Q data that is produced from an RTl-SDR dongle (RTL2832U) using the Osmocom RTL-SDR library. I have used I/Q data ...
0
votes
1answer
313 views

Choosing the best FM demodulation technique

I have an FM signal: 200 mVpp, 11.5 MHz carrier, max deviation - 500 kHz, modulating signal frequency range is 40-10000 Hz. And I need to demodulate it with highest SNR possible. The circuit has to ...
2
votes
1answer
60 views

Vestigial Side Band Demodulation: Which components are to be retained and which are to be filtered out?

This article shows the analysis of Vestigial Side Band Suppressed Carrier demodulation. I have understood the mathematical derivation up to eq (1). However, I am unable to understand which components ...
-4
votes
2answers
535 views

Is it possible to recover an over-modulated waveform?

Is it possible to recover an over-modulated waveform? I have searched the net up and down but I constantly come across the same answer 'It is not possible to fully recover a full AM signal using an ...