[SOLVED] different frequency of operation of Chua's circuit

[bhuwanmadan72]

I recently simulated chua's double scroll attractor in PSPICE with L=18mH C1=100nF and C2=10nF
which gave the output as


but FFT showed that the output has a frequency range of 2KHz to 3KHz


I want to use the chaos generated in secure communication so I could modulate my message signal over the chaos generated by tha chua's circuit but the frequency is in the range of audio signal.
so my question is that is there any other values of L,C1 and C2 which could give a different frequency?

 

[Audioguru]

We do not know what you are talking about because you forgot to post the schematic.

 

[bhuwanmadan72]

I didn't forgot, I intentionally didn't uploaded the schematic bcoz I mentioned the name "CHUA'S DOUBLE SCROLL CHAOTIC CIRCUIT"

 

[Audioguru]

If you don't post the schematic then I will not waste my time looking for it.

 

[bhuwanmadan72]

here's the schematic

 

[Audioguru]

You can use ultrasonic frequencies if you select opamps that work at a frequency that high and reduce the values in the LC tuned circuit.

 

[bhuwanmadan72]

that's what I am asking the circuit is very sensitive to the values of resistor between those capacitors
like in my case there is a range or R from 1.66k to 1.86k till it shows chaotic behavior otherwise not, and the taken conditions are giving me a frequency as mentioned above bot I need a higher ,at least double to what I am getting now, to modulate the audio signal.

 

[godfreyl]

To get double the frequency, halve the values of the inductor and capacitors.
To get 10 times the frequency, use 1/10 the value for the inductor and capacitors.
etc

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I want to use the chaos generated in secure communication so I could modulate my message signal over the chaos generated by tha chua's circuit

How do you propose to demodulate the message at the receiver?

 

[bhuwanmadan72]

ohk ill try this if it works..
at the receiver the same circuit with same values synchronous to the transmitter will be deducted from the received message,and the left over is the message signal with channel noise....

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help me plsss...

 

[godfreyl]

at the receiver the same circuit with same values

They will not give the same output.

In your simulator, try set up two identical circuits, but change the value of one component in one circuit by 1%. See how long they stay synchronised.

 

[bhuwanmadan72]

I have simulated a circuit in PSICE with same values of components and it showed the same synchronized output.

here's the schematic


as you can see the message signal is -0.5V to 0.5V with a time period of 1ms and the marker is the output of the circuit and the output is as shown

 

[godfreyl]

I have simulated a circuit in PSICE with same values of components and it showed the same synchronized output.

Maybe you missed this:

In your simulator, try set up two identical circuits, but change the value of one component in one circuit by 1%. See how long they stay synchronised.

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It is not possible to obtain perfectly matched components. There will always be some small difference between the component values in the two circuits.