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

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-7
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2answers
60 views

Can we send text data over FM radio? [on hold]

Can we able to broadcast text data over the FM radio.If yes, how can I implement this.
0
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1answer
44 views

USB to 3v converter to power a battery powered FM transmitter?

I have a SCOSCHE FM Transmitter which practically eats up 2xAAA batteries, I was thinking of using my TV's USB power for the transmitter. My search lead me to this 3 in 1 DC-DC USB 5V to 3.3V ...
3
votes
1answer
138 views

What is this type of radio fm antenna connector called?

I'm looking for an antenna replacement for my dad's busted radio (iHome IH8) and I'm having some trouble finding the name of this type of plug. The only things I find when searching online are coaxial ...
1
vote
1answer
74 views

Objections to use an RCA connector for antenna in broadcast FM receiver

Due to budget & space restrictions, I am thinking about replacing a PCB BNC connector used to attach an external FM antenna. It seems to me an RCA connector could be an option, given its good ...
2
votes
1answer
58 views

Triangulation with Single Tone FM TX and Three RX using Phase Detection [closed]

I'm looking for some IC and frequency suggestions to accomplish the following task. Modulate a tone onto a carrier and continuously broadcast this signal toward an array of three receiving ...
5
votes
3answers
275 views

Video Home System (VHS) bandwidth

Standard play VHS video cassette recorders offered only about 3 MHz luminance bandwidth by recording the signal on an FM carrier. What is that carrier frequency? Is it possible to confirm the carrier ...
1
vote
1answer
42 views

what is the function of pre-emphasizer and dee-emphasizer in Stereophonic FM Receiver?

what is the purpose of theses two block ? I know that pre-emphasizer will boost the high frequencies before transmission and dee-emphasizer will reducing them by a corresponding amount in the ...
0
votes
1answer
66 views

Detection of FM transmitter carrier phase

I would like to detect the phase (only) of a standard FM transmitter carrier over the air while it is modulated, while at the same time avoiding receiver threshold effect. Typical commercial FM ...
0
votes
0answers
20 views

How to prove FM is superior to PM for tone modulation for a given signal?

How to verify that for tone modulation FM is superior to PM for the signal x(t) where \$ x(t)= 8cos(\omega_0 t) + cos(5\omega_0 t) \$?
2
votes
1answer
70 views

FM Antenna Question

I am a swim coach trying to play music for my swimmers while they swim. I am currently using this transmitter with this antenna . I have no issues with the transmitter as it is more than powerful ...
0
votes
1answer
61 views

Question on Superherodyne Fm receiver to find the range of local oscillator and the image station …?

Consider a superheterodyne receiver designed to receive the frequency band of 1 to 30 MHz with IF frequency 8 MHz. a) What is the range of frequencies generated by the local oscillator for this ...
0
votes
0answers
35 views

Frequency separation in 2-FSK communication

I've started to post this question about the channel spacing (also called frequency spacing) and how is related to the doppler. But subsequently I've found a further possible problem, the frequecy ...
0
votes
1answer
129 views

Use Potentiometer to change frequency in FM Radio Transmitter

I know that in most circuits you use a tank circuit consisting of an inductor and variable capacitor in parallel to generate different frequencies like this one. However since most cheap trimmer caps ...
0
votes
1answer
58 views

Use Preformed inductor instead of coil for FM Transmitter

I want to build this transmitter: The inductor in the schematic says 0.1uh so I figured I could get some of these and use them instead of making my own like it describes in the picture. I would be ...
0
votes
1answer
141 views

555 timer as FM transmitter vs. Tank Circuit

This site seems to suggest the use of the 555 timer in astable mode to generate frequency modulation from a source. The typical transmitter uses a tank circuit with an inductor and trimmer capacitor ...
0
votes
2answers
296 views

How to remove the static sound in an fm transmitter

Hi I have a school project and I used the schematics from this website for our FM transmitter. Its actually working but its hard to recognize the music being played because of the static, also does ...
0
votes
0answers
74 views

Radio direction finding methods

I am a little bit confused about the different Radio Direction Finding methods and I want to chose the simplest method for what I want to do: find azimuth and elevation angle of arrival of my ...
1
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0answers
77 views

Superheterodyne receiver with voltage controlled oscillator

I'm new in electronics and I want to create a FM receiver that performs a product of the received RF signal and a local signal (the local signal is also frequency modulated with a Voltage Controlled ...
0
votes
0answers
24 views

How to measure the QoS of an anlog wireless link

I am working with FSK transmitter and modulator on the 433 MHz band, I am wondering how can I measure the QoS of the resultant link given that The receiver reports the received analog data only with ...
6
votes
3answers
328 views

Frequency spacing and the doppler effect

Suppose that I'm working on a system which needs to use a transceiver with an FM signal. If that system moves very fast (i.e. it is a satellite or whatever) in which the maximum doppler effect can be ...
1
vote
2answers
464 views

Using a Dipole Antenna on a 50 ohm FM transmitter

First of all, while I'm not new to electronics, I'm new to the radio world. I am helping a friend overseas set up a community radio, and am getting everything set up over here before I ship it. I ...
0
votes
1answer
67 views

FM signal example

Sorry if this question is too basic, but I'm a software engineer student who must study communication systems. I try to represent a FM signal in a graphing calculator, but I don't know why the result ...
0
votes
1answer
58 views

FM receiver used to control a switch

I am new to this and I would like to ask for advice on FM receivers. I want to create a very low powered (mass produced) item that has a super bright LED, battery and then related circuitry(for FM). ...
1
vote
1answer
1k views

How to build an FM transmitter and how does it work?

I have become interested in radio transmission and would like to know how to build an FM radio transmitter. When I search for information I either get a block diagram or a video of someone putting it ...
0
votes
1answer
40 views

Range of FM and Power

Why is the range of an FM signal shorter than AM signal? I thought it was due to the high frequency of FM signal getting absorbed by physical barriers. Is it so? Does power of a signal has any role to ...
-1
votes
2answers
174 views

Questions about FM receivers and transmitters?

I have a test tommorrow on phase lock loops, AM/FM receivers along with several other topics. I need to understand this topic clearly before I take the exam to advance to the next schooling in the ...
1
vote
2answers
112 views

Why feedback is needed in PLL FM Demodulator?

I am trying to build FM Demodulator in FPGA. The architecture I am trying to use is PLL-based FM Demodulator like the one below. I searched for the working principle of this demodulator but there is ...
1
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0answers
141 views

Problem with Constant Off-time PWM/Variable Frequency on dsPIC30F2020

I'm using the Microchip dsPIC30F2020. I've been trying for the longest time to get some sort of PFM signal for my project. I see in Section 12.4.7 there is the ability to have constant off-time PWM ...
3
votes
4answers
680 views

Does this simple RF transmitter circuit actually work?

I've come across this circuit a few times while searching for simple transmitter circuits, and decided to try it. According to this site, it should be transmitting at around 90Mhz. ...
1
vote
2answers
630 views

How to make a RF Choke?

I am a high school student and am making a project on FM receiver for class 11. I am following this circuit diagram: The L2 in this diagram is a 22µH RF Choke. The part listed in the website has ...
0
votes
3answers
134 views

There is a missing component in this circuit and couldn't figure out why?

I'm designing a BA1404 Stereo FM transmitter and I found the following source: Source Link You can find the component list, circuit scheme and the other stuff on this page. But when I look at the ...
1
vote
1answer
236 views

simple question regarding frequency modulation (FM)

I have a question on frequency modulation. For example, the following signal is frequency modulated: y(n)=sin(2*pi*(400+cos(2*pi*4*t))*t). Since the maximum of cos function is from -1 to 1, so I ...
-1
votes
1answer
106 views

Will BA1404 circuit work with TEA5591A

For an electronics project I would like to build stereo FM transmitter and receiver circuits. I was just wondering if these two circuits would work together. The BA1404 circuit can be found here. ...
0
votes
1answer
215 views

FM and phase/frequency deviation

I have a small understanding issue here, so I would be very glad if someone could help me a bit! We are given this FM modulated signal to volts; ...
0
votes
1answer
681 views

FM Radio transmitter and receiver circuits

I'm planning on building a FM transmitter and receiver circuit for an electronics project. I was just wondering if these two circuits would work together. Also would they be suitable for transmitting ...
1
vote
1answer
237 views

Which one of these transistors is equivalent to 2N918 NPN?

This is an FM radio receiver. Q1 is 2N918 NPN transistor but it is not available for me. Which one of the following transistors is more equivalent to Q1 ? BC547 TL431 s8550 s9014 2n5401 ...
1
vote
1answer
676 views

Why AM is preferred over FM in long distance communication?

In almost all long distance communication AM is preferred over FM. Do type of modulation has anything to do with this or it is just depending on transmitting frequency?
1
vote
1answer
238 views

Basic FM circuit

I have been messing around with a basic FM transmitter circuit, and I want to have a better explanation on how it works. I have searched around and found nothing. Can someone please explain how the LC ...
0
votes
1answer
157 views

FM Transmitter Amplifier — Maximum output power with non-customized parts?

I would like to build an FM transmitter on my own and I found a nice circuit that acts as a USB sound card to transmit low power FM signals. http://tipok.org.ua/node/35 My plan is to add another ...
-2
votes
2answers
56 views

Why frequency and coordinatino make sense in FM? [closed]

In FM modulation, the signal changes frequency depending on the amplitude of the original signal. So when you input the coordination frequency how does that makes any sense? For example, you input ...
0
votes
1answer
89 views

Radio Receiver IC

I am a Junior EE student that is interested in putting together a small radio receiver project for fun and to get some general practice with design. I have found these receiver chips from Silicon Labs ...
3
votes
2answers
166 views

Identify discriminator circuit?

The Dynaco FM-3 tuner uses what appears to be a Foster-Seeley discriminator with one diode reversed, or, if you prefer, a ratio detector without the third coil and stabilizing capacitor. The Dynaco ...
2
votes
1answer
522 views

Does amplitude of FM signal even matter?

Thinking about FM modulated signals that store information only in frequency so that their amplitude has no effect on the sound, I began to wonder: Does the amplitude even matter in the end? Well, ...
-2
votes
1answer
499 views

Problem solving super heterodyne receiver question

I have two problems which i am trying to solve but i am stuck on the half way. I have the following first question, which i am trying to solve I have solved the problem as following, ...
2
votes
1answer
539 views

How does this direct digital synthesis accumulator work?

So, I grabbed some code online and morphed it to work with my DE2-115 board, and now I need some help understanding exactly how it works. ...
4
votes
3answers
1k views

Capacitor between emitter and collector

Considering the circuit below.: What is the purpose of capacitor C5? I know it provides positive feedback to sustain the LC oscillations, but how does this work ?
0
votes
1answer
336 views

Streaming UHF/VHF/AM/FM over IP

I am working on a project that can stream TV and Radio signals over IP. I found a device to capture the signals and send them over IP realtek-rtl2832u but I am ...
-1
votes
1answer
567 views

FM transmitter feedback capacitor [closed]

Why is a capacitor connected across the collector-emitter of the transistor? How does this capacitor prevent decay of LC oscillations?
1
vote
1answer
325 views

Simple FM transmitter [duplicate]

How does this circuit perform Frequency modulation. I know the LC generates the carrier frequency. How does the transistor act as a varicap to perform FM. Which part of the circuit acts as a varicap ...
1
vote
0answers
359 views

simple schematic for 10.7MHz crystal-based marker generator

For FM tuner alignment purposes I want to build an outboard 10.7MHz marker generator to use in association with a piece of gear (ST1000A) that doesn't have one built in. They used to be available in ...