I am simulating a direct conversion receiver and I am interested in simulating the noise at baseband. The problem is that I get different results when using hbnoise with sweep-type relative harmonic=0 and absolute to sweep through the baseband bandwidth. Shouldn't it be identical as eventually the swept bandwidth is the same for both cases. Thanks in advance.
I meant to reply to this the other day. It sounds strange and I don't recall seeing this before. I'd be surprised if it's a bug in the simulator.
There's not really enough information to go on. Can you please provide:
Hi Andrew, Thanks for your response!, I am using IC6.17.713_SPECTRE16.10.284. The node I am plotting is the one from hbnoiseOut1. Thanks in advance! simulator lang=spectre global 0 parameters harm=9 flo=2G prf=-50include "netlist" simulatorOptions options reltol=5e-3 vabstol=1e-6 iabstol=1e-12 temp=27 \ tnom=27 scalem=1.0 scale=1.0 gmin=1e-12 rforce=1 maxnotes=5 maxwarns=5 \ digits=5 cols=80 pivrel=1e-3 sensfile="../psf/sens.output" \ dochecklimit=yes checklimitdest=both dcOpCheckLimit checklimit checkallasserts=yes severity=none dcOp dc write="spectre.dc" homotopy=dptran maxiters=150 maxsteps=10000 \ annotate=status dcOpInfo info what=oppoint where=rawfile hb hb tstab=80n saveinit=yes autosteady=yes oversample= + fundfreqs=[(flo/2)] maxharms=[harm] errpreset=moderate + tstabmethod=gear2only annotate=status+hbstb hbstb start=10 stop=300M dec=20+annotate=status hbac hbac sweeptype=relative relharmvec= start=10 stop=300M + dec=30 maxsideband=3 annotate=status hbnoiseOut1 ( vop von ) + hbnoise sweeptype=relative relharmvec= start=1k stop=200M + dec=5 values=[10 100] iprobe=PORT1 refsideband= + noisetype=timeaverage noiseout=[am pm usb lsb] + separatenoise=yes annotate=status krylov_max_iter=400 hbnoiseOut2 ( vop2 von2 ) + hbnoise sweeptype=relative + relharmvec= start=1k stop=200M dec=1 values=[10 100 100k] + iprobe=PORT1 refsideband= noisetype=timeaverage noiseout=[am + pm usb lsb] separatenoise=yes annotate=status + krylov_max_iter=400 primitives info what=primitives where=rawfile subckts info what=subckts where=rawfile asserts info what=assert where=rawfile
I delayed my reply until I did further investigations. First, The above error disappeared and I couldn't reproduce it. It disappeared after creating new maestro veiw!
Regarding your reply, I did noise sim "ALL" not "USB", as I was simulating phase noise simultaneously for other nodes (LO signal of a receiver) together with the Rx output at baseband (relative harmonic=0) or absolute (while sweeping the target baseband frequency range).I expected that regardless of ALL or USB, for the baseband signal, should get the same result. The issue is that when plotting USB noise after doing USB-noise sim or ALL-noise sim, I get different results. This I cannot understand. Also when plotting the noise summary, different components are having different contribution for ALL and USB noise sims. So which one can I trust?
Thanks for your support!