- #1
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Discussion Overview
The discussion revolves around troubleshooting an FM ratio detector circuit that is not producing an audio signal. Participants explore various aspects of circuit design, component values, and simulation versus physical implementation.
Discussion Character
- Technical explanation
- Debate/contested
- Experimental/applied
Main Points Raised
- One participant expresses difficulty in getting an audio signal from their FM detector circuit and seeks assistance.
- Some participants suggest using dedicated integrated circuits (ICs) for FM detection, citing specific models.
- Another participant compares the user's circuit to a standard design, indicating potential issues without specifying what those issues are.
- Several participants point out that there may be no connection from the AUDIO OUT line to the audio side of the detector.
- A participant mentions that the output from the detector should be audio output, questioning the circuit's design based on their reference material.
- One participant suggests that the simulation might require an AC analysis rather than a transient analysis to yield audio output.
- Another participant discusses the importance of ensuring that the transformer primary and secondary are tuned to resonate at the same frequency.
- A later reply indicates that a change in the value of the IF transformer resolved the issue for one participant.
- Another participant introduces a similar problem with their circuit and asks for clarification on which proposed solutions are appropriate.
Areas of Agreement / Disagreement
Participants express various viewpoints on the circuit's design and troubleshooting steps. While some solutions are proposed, there is no consensus on a single correct approach, and multiple competing views remain regarding the proper configuration and component values.
Contextual Notes
Participants note potential issues with component values and connections, but specific assumptions and dependencies on circuit design are not fully resolved.
Who May Find This Useful
Individuals interested in FM detection circuit design, troubleshooting electronic circuits, and those working with simulations versus physical implementations may find this discussion relevant.
- #2
Svein
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An FM detector is a complicated thing. I would use a dedicated IC - for example http://www.onsemi.com/pub/Collateral/ENA2052-D.PDF. You can also get the complete receiver in an IC: http://www.onsemi.com/pub/Collateral/EN8271-D.PDF.
- #3
NascentOxygen
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- #4
michael1978
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Hi, Svein, thank you i know, but i wil like this one to make it work,Svein said:
- #5
michael1978
- 434
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hello NascenOxygen, in my book it looks like this, so what do you think where is the problem?NascentOxygen said:
- #6
NascentOxygen
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There is no path linking your AUDIO OUT line to the audio side of the detector.michael1978 said:
- #7
michael1978
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from this circuit i did it in ltspice i thought he going to work but notNascentOxygen said:
is not audioouput the output from detector? of where is? in my book the output is taken from the audiooutput, after send to ic lm386 TO MAKE IT STRONGER THE audio signal...
- #8
- #9
michael1978
- 434
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sorry the voltage of SFFM must be 1V
- #10
Tom.G
Science Advisor
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Your circuit looks good to me.
Is it the simulation that does not work or the circuit that you built?
The simulation you posted is a Transient analysis. But you need an AC analysis to get audio output.
If the circuit you built is not working, do the usual troubleshooting. Check all wiring and make sure the parts are the right values.
Cheers,
Tom
Is it the simulation that does not work or the circuit that you built?
The simulation you posted is a Transient analysis. But you need an AC analysis to get audio output.
If the circuit you built is not working, do the usual troubleshooting. Check all wiring and make sure the parts are the right values.
Cheers,
Tom
- #11
michael1978
- 434
- 19
Hello Tom, i think that, the value of L2 L3 are not correct, but i going to try to looks everything is ok wiringTom.G said:
Have a nice day….
- #12
michael1978
- 434
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Hi Tom, i check all wiring, eveything is okey, i change the values of transformer, they change, but is not working.Tom.G said:
- #13
NascentOxygen
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The transformer primary and secondary are resonant circuits, and I think they are supposed to both be tuned to resonate at the same frequency. So as you sweep the input frequency, monitor the transformer primary and secondary signals and make sure their signal peaks do co-incide. Trim the capacitances until the peaks do coincide, and at the design frequency.michael1978 said:
Are you saying the simulation works okay, but your wired circuit does not? Or does neither work as expected?
- #14
michael1978
- 434
- 19
Thanks everyone i fixed……...
- #15
Tom.G
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How? What did you change to make it work?michael1978 said:Thanks everyone i fixed……...
- #16
- #17
Zlatko1969
- 14
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Hello
I have similar problem but with circuit I build not with simulation
which by the way show nothing,
I use BLUE i.f. transformer which should be FM detector and now from the answers above
which solution is proper.
1.This one where two 1nF caps connection goes to audio output before 7.5k resistor
2.This one where two 1nF caps connection goes to GND
thanks !
I have similar problem but with circuit I build not with simulation
which by the way show nothing,
I use BLUE i.f. transformer which should be FM detector and now from the answers above
which solution is proper.
1.This one where two 1nF caps connection goes to audio output before 7.5k resistor
2.This one where two 1nF caps connection goes to GND
thanks !