Independent noise sources in Orcad.

Hi everyone!
I am trying to simulatenoise contribution from a part for which there
is no vendor SPICE model.
Is there an independent noise source I could place on schematic in
orcad?
I am interested in both voltage and current noise sources.
Tried finding it in the libraries, but could not.

Thanks!
Best regards,
Pavel

 

[Jim Thompson]

On 9 Jun 2006 08:35:19 -0700, interpasha@hotmail.com wrote:

Hi everyone!
I am trying to simulatenoise contribution from a part for which there
is no vendor SPICE model.

What kind of part, BJT, MOSFET ?? Or a system?

Is there an independent noise source I could place on schematic in
orcad?
I am interested in both voltage and current noise sources.
Tried finding it in the libraries, but could not.

Resistor, diode ??

Thanks!
Best regards,
Pavel

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Charlie Edmondson]

interpasha@hotmail.com wrote:

Hi everyone!
I am trying to simulatenoise contribution from a part for which there
is no vendor SPICE model.
Is there an independent noise source I could place on schematic in
orcad?
I am interested in both voltage and current noise sources.
Tried finding it in the libraries, but could not.

Thanks!
Best regards,
Pavel

Ok, what type of noise source? White, pink, grey? What bandwidth? Is

this for an AC or transient simulation? How long are you simulating?

When you can answer all these questions, then you are ready to design
your own. No one noise source will do answer all of these, so they never
tried to design one. There is an app note on using a PRN generator to
write to a file to be used as a noise source in conjunction with a Vpwl
source. Or, just get your own list of random numbers...

Charlie

 

Thanks for the replies.

I wanted to get a source of white noise, but inserting the resistor
will affect other important parameters of the circuit, such as I/V.
What I really want is a component which does nothing other than produce
I or V noise in frequency domain.

I am doing an AC sweep, from 10kHz to 1MHz, flicker noise contribution
can be ignored.

Random number generator will not work, because as I understand it, it
will not be analyzed by PSPICE noise solver. It will simply show up on
the output as random variation.
+ its for time-domain, which I don't need.

 

[Jim Thompson]

On 9 Jun 2006 09:51:15 -0700, interpasha@hotmail.com wrote:

Thanks for the replies.

I wanted to get a source of white noise, but inserting the resistor
will affect other important parameters of the circuit, such as I/V.
What I really want is a component which does nothing other than produce
I or V noise in frequency domain.

I am doing an AC sweep, from 10kHz to 1MHz, flicker noise contribution
can be ignored.

Random number generator will not work, because as I understand it, it
will not be analyzed by PSPICE noise solver. It will simply show up on
the output as random variation.
+ its for time-domain, which I don't need.

Maybe use a resistor thru a behavioral E or G block?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.