Help with building this transformer in ltspice

  • #1
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Poster has been warned about substandard threads.
Hi,
everything oko_O
i just want to tell, can somebody, who have time just to read this file, you understand direct, if you know about fm detection, i just dont know how to make a transformer in ltspice, can somebody told how to make it this circuit with transformer and tuned please
 

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  • #2
berkeman
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So you know how to use standard transformers in LTSPICE, but are asking how to make and model tuned/adjustable transformers? What have you used transformers for in LTSPICE so far?
 
  • #3
434
19
So you know how to use standard transformers in LTSPICE, but are asking how to make and model tuned/adjustable transformers? What have you used transformers for in LTSPICE so far?
I never used, but i see one site, how to build an IF amplifier, so i se how to use couplin K1 L1 L2, but for example if its center tapped, i dont know, make tuned circuit, but i dont know for wich frequency, alse the transformer, they dont show the value,
you know is 4 smorgens, i am searching for the fm detector, why they hide, they tell you something and they dont finisho_O
 
  • #4
434
19
So you know how to use standard transformers in LTSPICE, but are asking how to make and model tuned/adjustable transformers? What have you used transformers for in LTSPICE so far?
I did something else in place of transformer, i did phase shift 90,
so this the file
PIC.png


is just a experiment i change the value of the last capacitor C4 0.01 in 0.01p alst the last resistor from 500K i make 8ohm, in place of transformer i use rc phase, and where is tuned circuit
is this ok? is in orde fm detector
 

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  • #6
434
19
This site shows FM Detectors and how they work. You probably want "Slope Detector" or "Ratio Detector."
https://www.radio-electronics.com/i...eption/fm-demodulation-detection-overview.php

An ordinary AM detector will work if the transformer is tuned a little bit off from the incoming frequency. This idea is a Slope Detector.
Goodmorning, hi, i read, but i dont know how to make a transformer in ltspice, is possible to make that circuits just transformer center taped, and for capacitor i read must be center to 10.7MHZ, i have no ide , ratio turns inductance, impedance:H
 
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  • #8
berkeman
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  • #10
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Hello, please somebody can help me with this, did a do it bad, of is correct, if is bad can soembody help to fix,(i am larning ltspice)
2.png
 

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  • #12
Baluncore
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The screendump you posted will not run on my version of LTspice. I need the .asc file.

If you post a screendump of LTspice output, you should also attach the compact text file.asc.txt to the post. That way, others can read the component values, or run the simulation.
If you need to post an LTspice screendump, reduce the LTspice window size first if possible, then use the LTspice “Tool”, “Copy bitmap to clipboard”. Use Paint to view and save the clipboard as a file.jpg or file.png before attaching it to your post.

You need to clearly identify the schematic of the circuit you are modelling. Are you using either fig 3, or fig 4, from the ARRL, QST, June 1985 article? The circuit you are modelling is significantly different to both those schematics.

You could stimulate an FM discriminator model with an FM current source. You are unnecessarily adding to the complexity of your circuit and simulation by following an earlier limiting amplifier with a cascode stage, just to drive the FM discriminator with an FM voltage source.
 
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  • #13
434
19
The screendump you posted will not run on my version of LTspice. I need the .asc file.

If you post a screendump of LTspice output, you should also attach the compact text file.asc.txt to the post. That way, others can read the component values, or run the simulation.
If you need to post an LTspice screendump, reduce the LTspice window size first if possible, then use the LTspice “Tool”, “Copy bitmap to clipboard”. Use Paint to view and save the clipboard as a file.jpg or file.png before attaching it to your post.

You need to clearly identify the schematic of the circuit you are modelling. Are you using either fig 3, or fig 4, from the ARRL, QST, June 1985 article? The circuit you are modelling is significantly different to both those schematics.

You could stimulate an FM discriminator model with an FM current source. You are unnecessarily adding to the complexity of your circuit and simulation by following an earlier limiting amplifier with a cascode stage, just to drive the FM discriminator with an FM voltage source.
hi, I make one other, i think is good(i hope), but i have problem to the audio output
 

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  • #14
434
19
The screendump you posted will not run on my version of LTspice. I need the .asc file.

If you post a screendump of LTspice output, you should also attach the compact text file.asc.txt to the post. That way, others can read the component values, or run the simulation.
If you need to post an LTspice screendump, reduce the LTspice window size first if possible, then use the LTspice “Tool”, “Copy bitmap to clipboard”. Use Paint to view and save the clipboard as a file.jpg or file.png before attaching it to your post.

You need to clearly identify the schematic of the circuit you are modelling. Are you using either fig 3, or fig 4, from the ARRL, QST, June 1985 article? The circuit you are modelling is significantly different to both those schematics.

You could stimulate an FM discriminator model with an FM current source. You are unnecessarily adding to the complexity of your circuit and simulation by following an earlier limiting amplifier with a cascode stage, just to drive the FM discriminator with an FM voltage source.
Thanks, this the fiile, can you look is good, how to make audio outpu?please
 

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  • #15
Baluncore
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Well that is a great little circuit. I have no idea where you might have got it from.
There are a few possible reasons why it might under-perform. If you want to learn, you will need to scratch your head and study the cryptic clues and the circuits.

1. The Q1 collector bias current will be insufficient to drive the discriminator. The last time I saw that circuit, it was mass produced in the switched AGC speed circuit of Icom's R71A communications receiver. It did not work there either.

2. The current supplied by V3 will be a little higher than you might expect, or the voltage a little less. LTspice really did not imagine that infinite impedance voltage source topology was possible, so it could not give an error message.

3. Where are the transformer winding phase dots? It appears that the transformer has been wound backwards on the three axes of a one gallon(US) Kline bottle.

4. D2 discriminator current flows like a very confused rat in a maze, without an exit. I have heard it said that rats leave a sinking ship, but your discriminator traps the rats. Don't worry, it is still floating, they will not drown. They are quite safe and quarantine is also secure, because they cannot run down the AF ratline since they are blocked by the thin layer of dielectric in C16.

5. Why do you short circuit the AF signal with 10,000uF caps, C4 & C5.

6. The output load R10 will weigh a little heavy on the circuit and so will also short circuit the discriminator output.

7. The model excitation IF frequency is a little high at 100 MHz, I would have expected 10.7 MHz.

8. The supersonic modulation might work with an automatic landing system, but it will not get through the AF stage, or your ears.

If you do not answer the questions you are asked, then you cannot be helped.
This is an infinite monkey circuit, it is a real gem. I will keep it for my scrap book.
 
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  • #17
434
19
Well that is a great little circuit. I have no idea where you might have got it from.
There are a few possible reasons why it might under-perform. If you want to learn, you will need to scratch your head and study the cryptic clues and the circuits.

1. The Q1 collector bias current will be insufficient to drive the discriminator. The last time I saw that circuit, it was mass produced in the switched AGC speed circuit of Icom's R71A communications receiver. It did not work there either.

2. The current supplied by V3 will be a little higher than you might expect, or the voltage a little less. LTspice really did not imagine that infinite impedance voltage source topology was possible, so it could not give an error message.

3. Where are the transformer winding phase dots? It appears that the transformer has been wound backwards on the three axes of a one gallon(US) Kline bottle.

4. D2 discriminator current flows like a very confused rat in a maze, without an exit. I have heard it said that rats leave a sinking ship, but your discriminator traps the rats. Don't worry, it is still floating, they will not drown. They are quite safe and quarantine is also secure, because they cannot run down the AF ratline since they are blocked by the thin layer of dielectric in C16.

5. Why do you short circuit the AF signal with 10,000uF caps, C4 & C5.

6. The output load R10 will weigh a little heavy on the circuit and so will also short circuit the discriminator output.

7. The model excitation IF frequency is a little high at 100 MHz, I would have expected 10.7 MHz.

8. The supersonic modulation might work with an automatic landing system, but it will not get through the AF stage, or your ears.

If you do not answer the questions you are asked, then you cannot be helped.
This is an infinite monkey circuit, it is a real gem. I will keep it for my scrap book.
HI, nut i repair all
2.png
 

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  • #18
434
19
Well that is a great little circuit. I have no idea where you might have got it from.
There are a few possible reasons why it might under-perform. If you want to learn, you will need to scratch your head and study the cryptic clues and the circuits.

1. The Q1 collector bias current will be insufficient to drive the discriminator. The last time I saw that circuit, it was mass produced in the switched AGC speed circuit of Icom's R71A communications receiver. It did not work there either.

2. The current supplied by V3 will be a little higher than you might expect, or the voltage a little less. LTspice really did not imagine that infinite impedance voltage source topology was possible, so it could not give an error message.

3. Where are the transformer winding phase dots? It appears that the transformer has been wound backwards on the three axes of a one gallon(US) Kline bottle.

4. D2 discriminator current flows like a very confused rat in a maze, without an exit. I have heard it said that rats leave a sinking ship, but your discriminator traps the rats. Don't worry, it is still floating, they will not drown. They are quite safe and quarantine is also secure, because they cannot run down the AF ratline since they are blocked by the thin layer of dielectric in C16.

5. Why do you short circuit the AF signal with 10,000uF caps, C4 & C5.

6. The output load R10 will weigh a little heavy on the circuit and so will also short circuit the discriminator output.

7. The model excitation IF frequency is a little high at 100 MHz, I would have expected 10.7 MHz.

8. The supersonic modulation might work with an automatic landing system, but it will not get through the AF stage, or your ears.

If you do not answer the questions you are asked, then you cannot be helped.
This is an infinite monkey circuit, it is a real gem. I will keep it for my scrap book.
Hello, cant see sinewave please can you hep me, i dont know man
 
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  • #19
Baluncore
Science Advisor
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You wanted a SPICE transformer. Before you got it working you added an irrelevant and unnecessary cascode circuit to drive it, instead of a differential limiter amp. Before you got that driver working with the transformer and FM discriminator you added what looks like an audio amplifier. When adding complexity does not make it work, you add more complexity. Your simulation was doomed to failure because you increased complexity when you should have reduced complexity.

You were given a functional transformer model, but you appear to have no idea what you were given because you have broken it again and again. Your latest screen dump shows it is still not a transformer. But there is no .asc file to confirm that.

You have been given functional transformer models, but you appear to have no idea what you were given because you have broken it again every time. In your post #17 it appears not to be a transformer, because you show no coupling coefficients. Again there is no .asc so you cannot be helped.

SPICE was designed to model small isolated modules, not complete systems such as communication receivers. The speed and accuracy of a simulation is greatly reduced by mixing different circuits in one model. If you do not know your circuit you cannot model it with SPICE.

You are clearly using the infinite monkeys technique, with cut and paste, to draw your idea of what a schematic should look like, as a work of art. There is no possibility of you understanding electronics by using that technique.

You are probably blind to the fact that your fundamental approach guarantees your simulation will fail. It is unproductive and very costly for anyone who tries to help you. I have wasted too much time here.
 
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  • #20
434
19
You wanted a SPICE transformer. Before you got it working you added an irrelevant and unnecessary cascode circuit to drive it, instead of a differential limiter amp. Before you got that driver working with the transformer and FM discriminator you added what looks like an audio amplifier. When adding complexity does not make it work, you add more complexity. Your simulation was doomed to failure because you increased complexity when you should have reduced complexity.

You were given a functional transformer model, but you appear to have no idea what you were given because you have broken it again and again. Your latest screen dump shows it is still not a transformer. But there is no .asc file to confirm that.

You have been given functional transformer models, but you appear to have no idea what you were given because you have broken it again every time. In your post #17 it appears not to be a transformer, because you show no coupling coefficients. Again there is no .asc so you cannot be helped.

SPICE was designed to model small isolated modules, not complete systems such as communication receivers. The speed and accuracy of a simulation is greatly reduced by mixing different circuits in one model. If you do not know your circuit you cannot model it with SPICE.

You are clearly using the infinite monkeys technique, with cut and paste, to draw your idea of what a schematic should look like, as a work of art. There is no possibility of you understanding electronics by using that technique.

You are probably blind to the fact that your fundamental approach guarantees your simulation will fail. It is unproductive and very costly for anyone who tries to help you. I have wasted too much time here.
Thanks Balounce, i know you help a lot, but this time sir Audioguru he help to fix it, thanks from Audiguru, And Thank from you, you explain things very good, thanks, now i am trying to learn ltspice 4 simulation, i find that book in internet, of do you know something tp learn with spice simulatio, have a nice day:partytime:
 
  • #21
berkeman
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Thread is closed for Moderation for a bit...
 
  • #22
berkeman
Mentor
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Thanks Balounce, i know you help a lot, but this time sir Audioguru he help to fix it, thanks from Audiguru, And Thank from you, you explain things very good, thanks, now i am trying to learn ltspice 4 simulation, i find that book in internet, of do you know something tp learn with
Thread will remain closed. @michael1978 -- please check your private messages. Thank you to @Baluncore for trying so hard to help out the OP in this thread. :smile:
 
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