Hi,

I am designing a receiver and need to find out total output noise in the bandwidth of interest. The structure of the receiver is as given below,
- Gm-Stage
- Passive mixer for downconversion (LO - 1.1GHz, BW - 1GHz)
- Active integrator structure to provide built in sinc anti-aliasing filter
  - the integrating caps are discharge after a certain time window. no feedback resistor.
  - two integrators working in different phases and interleaved output

I am having certain problems while doing Pxf and Pnoise simulations,

(1) Without the mixer, I do get the expected sinc response in Pxf analyis with the appropriate DC gain. When I put the mixer, there is a lot of attenuation in the gain.

(2) There is a peak in the PNoise analysis, output noise plot at 1GHz

Please help me in regards to this issue.
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