LTSPICE signal+noise simulation

E

ERER

New Member

• May 22, 2019

• #1

Hi

I would like to simulate such signal (Attached)
Can someone help me how to do it ?

Thanks !

 

ronsimpson

Well-Known Member

Most Helpful Member

• May 22, 2019

• #2

In LTspice, use a "behavioral voltage source" component in series with the signal source you need to make noisy. Set as "V=(rand(time*1e18)-0.5)*1.0".

Two signals in series. The outputs will add together. One signal is "signal" the other is random.

 

E

ERER

New Member

• May 23, 2019

• #3

Hi
Thanks for the support

I've did it
The problem is that the noise is on top the signal

I need a clear signal but with some noise floor

 

ronsimpson

Well-Known Member

Most Helpful Member

• May 23, 2019

• #4

ERER said:

need a clear signal but with some noise floor

Click to expand...

Do not understand.

 

E

ERER

New Member

• May 23, 2019

• #5

Hi

I need along with the signal a random noise across zero
Like this:

 

ronsimpson

Well-Known Member

Most Helpful Member

• May 23, 2019

• #6

That is two signals.

 

E

eTech

Well-Known Member

• May 23, 2019

• #7

Hi

Use Ron’s example but try white() function with random() function instead.

eT

 

E

ERER

New Member

• May 23, 2019

• #8

Ok my friend
But how can i simulate those two signals on one same line ?
Now the noise is over my signal, and i dont want it...

 

ronsimpson

Well-Known Member

Most Helpful Member

• May 23, 2019

• #9

Erer,
Your words are not working for me.
Do you want one or two signals?

 

alec_t

Well-Known Member

Most Helpful Member

• May 23, 2019

• #10

ERER said:

But how can i simulate those two signals on one same line ?

Click to expand...

A signal line cannot be at two different voltages at the same time.

 

ronsimpson

Well-Known Member

Most Helpful Member

• May 23, 2019

• #11

If you really want "one" but have "two" you could make a component that has these two voltage sources inside. (it will look like one)

Is this what you want?

 

E

ERER

New Member

• May 23, 2019

• #12

ronsimpson said:

If you really want "one" but have "two" you could make a component that has these two voltage sources inside. (it will look like one)
View attachment 118434
Is this what you want?
View attachment 118435

Click to expand...

YES ill try

 

alec_t

Well-Known Member

Most Helpful Member

• May 23, 2019

• #13

Something like this? :