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.
340 questions
-3 votes
0 answers
54 views
Easiest and most efficient way to alter the pulse width on a muscle stimulator [closed]
I want to thank the forum in advance for all the help provided. I am desperate to get this problem figured out. A little background as to why I am trying to do this…..I have an electronic muscle ...
- 1
0 votes
2 answers
150 views
FM modulation circuit, if it were built without utilizing a varactor diode?
The aim is to construct an FM modulator circuit with a 10kHz carrier signal and a 1kHz audio signal. I experimented with different component values to enhance the circuit's performance. V2 represents ...
- 41
1 vote
3 answers
165 views
Choice of LO for Gilbert cell mixer and ADC sampling
I am making my own superheterodyne radio for receiving FM broadcast radio, and I want to be able to use an ADC for sampling and processing. The ADC's available on the market are quite pricy at the ...
- 27
-1 votes
2 answers
131 views
FM IF wideband amplifier: how does it work? [closed]
I'm trying to build something (a simplified replica of the Pioneer PR-7820, the first LaserDisc player), but I've run across a problem. The player includes an IC known as the TA7302P, which is ...
- 385
1 vote
0 answers
78 views
Optimum FM bandwidth [closed]
Broadcast FM is called wideband . Voice communications FM is called narrowband .Bandwidth is related to deviation and modulating frequency by bessel functions or approximations like Carson's rule....
- 16.3k
1 vote
3 answers
176 views
Does this schematic work as an FM transmitter?
\$V_{out}\$ is connected to an antenna. This is a schematic which is used to create an FM signal. Does the transistor U2 work both as an oscillator and a mixer?
- 1,127
1 vote
1 answer
107 views
Do I need transistor Q1 if I only use audio jack?
Here is the schematics of the FM radio transmitter kit. I bought. this support both microphone and audio jack. What will happen if I remove Q1 if i only use audio jack?
- 1,127
1 vote
6 answers
234 views
What does an FM module do, and why doesn't an AM radio need some sort of equivalent?
I built an AM crystal radio, and what I loved about the project was that it wasn't rote assembly; as I put it together I learned what every part did. And given it was such a simple thing, I learned ...
2 votes
1 answer
249 views
Why does my FM transmitter work in a SPICE simulation but not in the real world?
Here is my FM transmitter schematic: Here I provide a google link for this PDF (Schematic PDF). I simulated this with LTSpice, and it is working around FM radio frequency. When I build the circuit in ...
- 1,127
4 votes
1 answer
128 views
FM Bessel Function Question:
I have a device (1980s era broadcast VTR) that takes a video signal from DC to 4.2 MHz and positive FM modulates a frequency bandpass of 14.18 MHz to 20.0 MHz. Now just before the final video record ...
- 61
1 vote
2 answers
139 views
Colpitts oscillator + Common Collector buffer for antenna touch stability
I am trying to create an ultra low energy FM transmitter that can transmit sound over a distance of about 50cm. I used a Colpitts oscillator and it seemed to work fine, however touching the antenna ...
2 votes
2 answers
189 views
FM upconverter using JFET and LC oscillator
I'm simulating an JFET multiplier circuit in Proteus based on a 2N3819 and an LC tank oscillator, my goal is to upconvert the FM signal centered in 100 kHz to a higher frequency (200 kHz) My attempt ...
-1 votes
1 answer
55 views
How well can FM telemetry transmit remote amplifier baseline noise?
Can FM telemetry transmit a remote differential amplifier baseline noise faithfully? If not, how would the FM distort the baseline noise of the remote amplifier that is frequency modulated and ...
- 1,093
0 votes
2 answers
102 views
Dual Channel RF Synthesizer with Frequency Sync Capability
I have an application involving modulation/demodulation with a 20-40 MHz frequency that I need to apply in two places with controlled phase offset. I usually do this with something like the Rigol ...
- 9
0 votes
2 answers
141 views
Why does this phase shifting network attenuate the input signal?
Below shows the phase shifting network I designed for a FM detector. The goal is to create a 90° phase shift between the input and OUT1 at the centre frequency 10.7MHz. This circuit drives the bottom ...
