Need your help about noise analysis in spectre!

[colinwang]

Could anyone be please to tell me how to simulate noise in spectre?
My step is:
1 choose noise analysis
2 set sweep varialbe as frequency
3 sweep range start 1 stop 800k
4 Out put noise: positive output node I choose the output of the circuit, negative output node I choose the gnd
5 Input Noise I choose the voltage source in the beginning of the circuit(vin)
But the result is quite different from the one I've got from the hspice. The hspice code is: .noise v(out) vin 1000
What's the reason?
Thank you for your help!
Regards
Colin

 

[selvaraja]

step 4 : ouput noise two option voltage/probe .... if u choose probe u need use port at output select on port

 

[wonbef]

i am fuzzy about it. i hope somebody can give a clear analysis step of noise analysis (input referenced noise, total output noise, ...) in spectre simulator. thanks in advance!


kind regards,

 

[colinwang]

Thank you! I choose the output noise voltage, and the positive output node is out while the negative output node gnd!
I've also found some other questions. If I choose the sweep range as start 0, stop 1000k, the result is quite different from start 1, stop 1000k. What's the reason?Here is the image of the noise analysis.
Regards!
Colin
**broken link removed**