Cadence recommends following way to do the noise simulation in Complex filters: -According to principle of superposition noise can be calculated as follows:1. Calculate output noise (V**2/Hz) when only portI is active:- at Iout: Ioutn_I(f);- at Qout: Qoutn_I(f).2. Now calculate output noise (V**2/Hz) when only portQ is active:- at Iout: Ioutn_Q(f);- at Qout: Qoutn_Qf).Now you can calculate the total otput noise (V**2/Hz) at both outputs:Ioutn(f) = Ioutn_I(f) + Ioutn_Q(f);Qoutn(f) = Qoutn_I(f) + Qoutn_Q(f);______________________________________________________________________________The complex BPF is made of 2 LPFs. Both of them have gain = 0dB. Also Gain is 0dB for complex out to complex input. Now
I see that input referred noise is double that of output referred noise
even though gain is 0dB . I don't know why this is happening. Please
You don't say what type of noise analysis you are running.... Is this ac noise, spectreRF pnoise, etc. ?
For a summary of existing noise documentation, you may want to take a look at:
Summary of existing documentation on various RF related noise analyses
(I suspect that you may be referring to COS Solution 11162588 . You may want to consider filing a Service Request so that a Support AE can assist you in greater detail.)
Sr. Staff Support AE, Global Customer Support
Cadence Design Systems, Inc.
In reply to Tawna:
Thanks for replying. I am performing AC Noise analysis.
Please let me know what do you think on the stated problem.
I will file an SR on this.