Skip to main content

Questions tagged [frequency-modulation]

For questions relating to frequency modulation (FM). This is a scheme where a carrier is modulated by varying its frequency to carry information.

Filter by
Sorted by
Tagged with
-2 votes
1 answer
95 views

Is there any way to speed up simulation in Ltspice? [closed]

The following is my FM transmitter circuit. It takes about 1 minute to simulate. In real life, I want to use this BFQ19SH6327XTSA1 from Infineon instead of 2N22222. (link datasheet) and download link ...
kile's user avatar
  • 897
1 vote
2 answers
131 views

Will this FM transmitter work?

I found this schematic on circuit digest. I have tried to simulate it in LTspice. That's the wave I got from the simulation. Most of time it's just DC and does not oscillate at all. Is this going to ...
kile's user avatar
  • 897
3 votes
2 answers
69 views

Numbers in Generating Phase Coherent Electronic Systems

I am reading the following paper 'Störmer’s numbers in generating phase coherent electronic systems' written in 1969. More or less I understand that in microwave applications there is clearly a use ...
Mikhail Gaichenkov's user avatar
1 vote
0 answers
65 views

Guidance on development of FM radio [closed]

I am in the process of learning all about FM/AM and already have managed to make my own working transmitter. All these are some starting steps in order to make my own FM radio. Regarding that, I would ...
Gregory Kafanelis's user avatar
0 votes
0 answers
69 views

Accessing the FM 19kHz Pilot?

How can one attach an oscilloscope probe to the mono mode output of an FM station to pick up the 19kHz pilot (normally used for stereo)? Is it expected that FM tuners such as the RDA5807 will, in mono ...
James Bowery's user avatar
-2 votes
4 answers
117 views

How can an audio signal with varying frequency be modulated using FM? [closed]

An audio signal can have varying frequency and amplitude and both are the part of the information. As I understand it, frequency modulation is a technique where the frequency of the carrier wave is ...
Ritam Sarkar's user avatar
-1 votes
1 answer
47 views

Sending control signal via FM

Is it possible to send different signals to a receiver using FM which then the receiver would be able to distinguish between and do a set act based on the signal? How to? For example, the transmitter ...
adam_Barfi's user avatar
5 votes
2 answers
746 views

What is this circuit? (FM detector?) - LTspice

I have this circuit from college (almost 15 years ago) that is through-hole components wired together and it picked up the strongest local radio station. I now can't get it to work, so I'm wondering ...
tlab's user avatar
  • 51
0 votes
1 answer
69 views

Is FM ever used for digital radio transmission [closed]

The idea would be to transmit multiple bits(or frames) with each cycle of the RF oscillator. So you would use a 64-bit DAC to convert the digital data stream into an analog signal, frequency modulate ...
Mr X's user avatar
  • 734
1 vote
1 answer
90 views

Designing FM Transmitter [closed]

I am a student and I want to learn how to practically design a FM Transmitter circuit, I have this circuit here and I would be grateful if someone could tell me how to calculate and select all the ...
copperwire's user avatar
0 votes
1 answer
59 views

Controlling a IR2110 with PFM for Half Bridge Circuit [closed]

I am curious about how to select Cboot for desired control frequency range. https://www.infineon.com/dgdl/Infineon-Bootstrap_Network_Analysis-ApplicationNotes-v01_00-EN.pdf?fileId=...
MSB's user avatar
  • 77
1 vote
1 answer
148 views

Is it possible to receive an FM signal without a tank circuit?

I was broadcasting FM signals at MHz frequencies in my room. I know that an AM radio will not work to receive FM transmissions. The special issue is that an AM radio can get any AM signal without a ...
user avatar
0 votes
2 answers
161 views

How to design an RF frontend for an FM receiver

I'm designing a RF receiver for FM Radio. I simulated the circuit in LTspice and got an output as shown below: This is OK, but I would like the gain to be 24 dB across the range of 88-108 MHz. The ...
TheButterMineCutter's user avatar
-1 votes
1 answer
119 views

Frequency demodulation circuit

This is how I designed the frequency modulation circuit, but I cannot perform the demodulation process. It can be done with a PLL but I couldn't install it. How can I demodulate?
Orhunemre's user avatar
1 vote
2 answers
137 views

How does this metal detector circuit work with an AM receiver?

I do not understand how this circuit works. From Fun Electronics Projects for the Experimenter by Newton C. Braga. It is described as using the beat-frequency method to detect an object. The ...
Maro2058's user avatar
0 votes
2 answers
44 views

Does the microphone input interfere with the headphone jack input?

In this circuit, there are two inputs to the FM signal. One is from the microphone, another is from the headphone jack. Does the the microphone input interfere with the headphone jack input? Can ...
user116083's user avatar
0 votes
0 answers
29 views

Why is it difficult to write the close loop transfer function of a frequency modulated DC-DC converter (for eg - LLC converter)?

I know how to derive and write the transfer function of duty cycle/pulse width modulated DC-DC converter. We need to linearize the switches and then write KVL/KCL equations and then derive the output ...
Sudhanva Gokhale's user avatar
1 vote
1 answer
137 views

RF signal on Audio/Music/Guitar equipment

It is looking like the standard RF noise from my (new to me) old apartment wiring through my amp to my speakers. Suspected it could be due to poor guitar shielding/grounding, bad cables etc. Started ...
Daniel's user avatar
  • 11
0 votes
1 answer
257 views

Demodulation of FM signal frequency

After playing with homemade AM radios, I noticed that it is boring to broadcast AM signals all alone. I have also noticed that the AM stations around us, are so limited that I had no other chance than ...
user avatar
0 votes
0 answers
71 views

What can be done to increase the dynamic range of a FM receiver?

If i have to receive a signal from a far away FM station, nearby stations swamp the receiver if they are both nearby physically or nearby in the spectrum. I believe the AGC in my radio is cutting out ...
Jorge Aldo's user avatar
1 vote
0 answers
183 views

What could be blocking communication with TDA7706S on a Sony GT520U radio?

I have a Sony GT520U radio which started developing a lot of noise and becoming unresponsive when in tuner mode. Opening it revealed the chipset on the tuner was overheating in less than 3 minutes of ...
KE Keronei's user avatar
0 votes
1 answer
347 views

How to make very low range FM Transmitter?

I am experimenting with building an FM transmitter. I want to make it only have a range of a few meters so I can detect it on my radio at home at a distance of a few meters. The circuit diagram is ...
LEXOR AI's user avatar
  • 346
2 votes
1 answer
60 views

Simple detection of a transient FM frequency shift

I have an application with a 2D array of inductive sensors for position detection of an object on a plane. I have experimented with inductance to digital converters (https://www.ti.com/product/LDC1314)...
learnvst's user avatar
  • 1,341
2 votes
2 answers
533 views

FM receiver with 2N3904

Please explain how these 2 transistors work. I don't understand how it active an amplify the signal. Source: https://circuitdigest.com/electronic-circuits/simple-diy-fm-receiver-circuit-on-internet
Quang Đạo Đoàn Trần's user avatar
1 vote
0 answers
88 views

Modern approach of creating VHF FSK (FM) recieeiver

I need to make a narrow band FM receiver for the VHF band. More specifically, not even FM, but FSK. The operating frequency range should include from 35 to 40 MHz. Frequency deviation is around 0.5 to ...
Dj Obsidian's user avatar
0 votes
1 answer
150 views

Antenna tuner for 1MHz to 150MHz

I am trying to build an antenna tuner for my 2m (1m + 1m) dipole antenna. It has a 1:1 balun and is connected to a coaxial cable which is connected to my radio with an impedance of 50 ohm. I can't ...
Remo's user avatar
  • 1
2 votes
2 answers
338 views

Broadcast FM: Where is the pre-emphasis applied?

A DSP guy like me should know this, and I think that I do, but I can't seem to find a definitive answer in my Carlson Communications Systems textbook. We know that FM is like phase-modulation (PM) but ...
robert bristow-johnson's user avatar
0 votes
0 answers
48 views

How phase is modulated according to our message signal?

My question: let message signal m(t) be sin(w1t).For frequency modulation (instantaneous phase deviation=phi(t)) d[phi(t)]/dt=kf m(t) so i get that at 90° or π/2 frequency will be max because the ...
user305532's user avatar
1 vote
2 answers
144 views

Why is my LC oscillator PCB design not working?

I'm building a simple FM transmitter to learn more about LC oscillators. I've successfully designed and built the following transmitter on a bread-board and perf-board using standard through hole ...
Movieboy's user avatar
  • 217
0 votes
0 answers
210 views

IQ data for analog FM modulation

I am trying to understand how I can produce analog FM modulation using IQ data. So far, I know to generate the FM modulation with an IQ modulator (like the LTC5599.) I have to apply IQ data in ...
Grag's user avatar
  • 1
1 vote
1 answer
261 views

STM32 FM Transmitter using PWM limitations?

As a learning experiment, I am trying to use PWM to transmit audio in the FM band (80MHZ - 108Mhz). Currently, I have a PWM output with a prescaler of 0, ARR of 1, and pulse width of 1. Since I'm ...
Movieboy's user avatar
  • 217
0 votes
4 answers
554 views

AM Receiver Antenna Coil

In almost all the radio receivers whether FM or AM, custom wire-wound coils are used that are wrapped on a ferrite core usually (not always) of 100 mm x 10 mm dimensions. Is it possible to use fixed ...
Awais Mushtaq's user avatar
2 votes
1 answer
580 views

Why does the frequency deviation of a FM wave have different definitions?

Source 1 defines the modulation index in the expression for FM as follows: As per the expression for frequency modulated wave, isn't the frequency deviation same as Modulation index 'M'? "The ...
Dynamic_equilibrium's user avatar
0 votes
1 answer
269 views

How to adapt a FM reciever circuit to use a varicap diode instead of a trimmer capacitor

My team and I are interested in learning about FM communication and decided to build a simple FM receiver before building a proper transmitter. We looked at some circuits on the web, and they all seem ...
Candy Hi's user avatar
  • 141
0 votes
4 answers
119 views

Weird component in radio player interferes with FM functionality of the radio itself

I got my hands on an old radio player which has both cassette player and FM/AM functionality. I got constant noises while playing on FM and it turns out to be some weird component on the cassette ...
Harish Aathiyan's user avatar
1 vote
2 answers
355 views

LoRa - Frequency Shift Chirp Modulation - chips in a symbol

I am trying to create a form of FSCM (frequency shift chirp modulation) based on LoRa principle just to learn from it and to obtain a deeper understanding. What I do not get: why is (or must be?) the ...
Mart's user avatar
  • 376
-1 votes
2 answers
266 views

FM receiver circuit [closed]

I am doing a college project where I have to build an FM receiver. I didn't have a lot of knowledge about the subject before starting my research. Now, I understand the function of the principal ...
Foutri's user avatar
  • 1
1 vote
3 answers
435 views

Frequency upconversion from 1 to 100 MHz for FM transmitter

I'm trying to build an FM transmitter like pifm but using the ESP32. I can generate an FM signal at the DAC output of the ESP32 with a carrier frequency of 1 MHz and a deviation of 25 kHz, but in ...
Hamdon's user avatar
  • 11
0 votes
0 answers
86 views

Need help with signal modulation

To capture a mammalian cell, I need to have a constant 4MHz AC signal (coming from a function generator) while sweeping the frequency from the vector network analyzer (VNA) 9kHz to 9GHz to read the ...
Ferrofluid's user avatar
0 votes
1 answer
1k views

Band selection circuit for SI4825 A10

Following the official schematic and guideline (AN738: Si4825/36-A Antenna, Schematic, Layout, and Design Guidelines), I am building a Si825 A10-based radio receiver. I am getting weak audio output ...
digiwizkid's user avatar
2 votes
1 answer
485 views

Why doesn't this FM receiver work in LTspice?

After years, I'm back again to the electronic world. To start off, I just tried to simulate this circuit in LTspice: Source Here is what I've done in LTspice: But it doesn't work. Here is a ...
Roh's user avatar
  • 4,650
0 votes
1 answer
441 views

FM Circuit Simulation

I tried to simulate a circuit that I found in google. I adjusted some of the values in the tank circuit but the output waveform resembles that of amplitude modulated wave. What could possibly be wrong ...
Jugulis's user avatar
  • 11
0 votes
2 answers
305 views

FM demodulation circuit

I'm doing an FM demodulator circuit. I am copying the circuit from LTspice in the first image) to Multsim (the second image.) Is what I did in Multisim correct? How can I get a graph from Multisim ...
janna urb's user avatar
-4 votes
3 answers
399 views

What is the method to mute sound during seek on RDA5807 FM?

How to does noise canceling work on thisRDA5807M FM radio module? What can I do to mute noise on the radio? I want to mute immediately when there is blank white noise on the FM radio.
Coder1448's user avatar
0 votes
1 answer
1k views

Can telescopic FM/DAB antenna be replaced by Coax?

I tried to search for this prior to asking but with no luck... I have an FM/DAB+ antenna like this: from which a standard 75-Ohm Coax is coming down and I would like to connect it to the radio (...
player0's user avatar
  • 103
0 votes
1 answer
259 views

How would a modulated and demodulated signal differ in FM and PM? Simulink Simulation

I am trying to observe the differences of phase and frequency modulation. On the figure below, the left scope shows a frequency modulation and demodulation whereas the right scope shows a phase ...
Kalamakra's user avatar
  • 173
0 votes
4 answers
191 views

FM transmitter won’t work. I need help with more gain, and current at the output

I am trying to make an FM transmitter circuit using cascaded transistors. My two input signals are from a microphone and from an 80 MHz crystal. I’ve calculated a gain of 22 from the first stage and ...
Sean772's user avatar
  • 19
0 votes
2 answers
322 views

FM transmitter not giving the intended output of 88MHz to 108MHz

I am trying to build an FM transmitter that outputs 88MHz to 108MHz range using Multisim, but the circuit I constructed gives a lower voltage and lower frequency at the output according to the ...
Dillon's user avatar
  • 9
0 votes
2 answers
310 views

Transmit beeps from Arduino through FM transmitter circuit

I am trying to create a simple Arduino parking sensor that sends the warning beeps to the car radio using FM transmitter circuit. I searched different FM circuits and found many of them that use a ...
Mohamed Anwer's user avatar
1 vote
1 answer
125 views

Frequency Modulation - Why don't we modulate the carrier by multiplying message signal m(t) directly with f_car?

I am master student of computer science and I have got a problem/question from the domain of communication engineering. So: I'm listening to a lecture that's about Layer 1 stuff, and recently we ...
Atzeschmoss's user avatar

1
2 3 4 5
7