Cadence® system design and verification solutions, integrated under our System Development Suite, provide the simulation, acceleration, emulation, and management capabilities.
System Development Suite Related Products A-Z
Cadence® digital design and signoff solutions provide a fast path to design closure and better predictability, helping you meet your power, performance, and area (PPA) targets.
Full-Flow Digital Solution Related Products A-Z
Cadence® custom, analog, and RF design solutions can help you save time by automating many routine tasks, from block-level and mixed-signal simulation to routing and library characterization.
Overview Related Products A-Z
Driving efficiency and accuracy in advanced packaging, system planning, and multi-fabric interoperability, Cadence® package implementation products deliver the automation and accuracy.
Cadence® PCB design solutions enable shorter, more predictable design cycles with greater integration of component design and system-level simulation for a constraint-driven flow.
An open IP platform for you to customize your app-driven SoC design.
Comprehensive solutions and methodologies.
Helping you meet your broader business goals.
A global customer support infrastructure with around-the-clock help.
24/7 Support - Cadence Online Support
Locate the latest software updates, service request, technical documentation, solutions and more in your personalized environment.
Cadence offers various software services for download. This page describes our offerings, including the Allegro FREE Physical Viewer.
Get the most out of your investment in Cadence technologies through a wide range of training offerings.
This course combines our Allegro PCB Editor Basic Techniques, followed by Allegro PCB Editor Intermediate Techniques.
Virtuoso Analog Design Environment Verifier 16.7
Learn learn to perform requirements-driven analog verification using the Virtuoso ADE Verifier tool.
Exchange ideas, news, technical information, and best practices.
The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information.
It's not all about the technlogy. Here we exchange ideas on the Cadence Academic Network and other subjects of general interest.
Cadence is a leading provider of system design tools, software, IP, and services.
Get email delivery of the Cadence blog featured here
Two of the most important parameters for accuracy are: (1) maxharms(2) oversample maxharms:The accuracy of HB is greatly dependent on the number of harmonics chosen. As a general rule, you should simulate with with maxharms [5 3] and (if memory allows) re-simulate with maxharms [7 3] to see if the answer changes (or not). If the answer does not change, you can be confident about your results.For circuits with dividers, the number of harmonics chosen should equal 5 times the divide ratio. This is regardless of whether you are using the shooting or HB engine.examples:
You are simulating with PSS and (say) the L0 input is 400M. There is a divide by 4 in your circuit, so the PSS beat frequency is 100M.You will need 5x4= 20 harmonics. For QPSS, if you have a divide by 4 with these frequencies: Mixer LO=400M, RF=100M+1M, you'll need [20 3] for your maxharms. Also, you'll need to set the freqdivide parameter in the qpss Choosing Analyses form in ADE to 4.oversample: The harmonic balance algorithm contains the Fourier Transformation. If oversample=1 (which is the default) and the harmonics number is K, then there will be (2K+1) samples in one period of waveform. If the oversample=S, there are (2K+1)*S samples. Increasing the number of oversamples will result in more sample points in the time-domain, and thus the HB spectrum and subsequent noise calculation will be more accurate. Unlike the harmonic number (maxharms), oversample only affects the number of samples in the time-domain, and won't increase the number of unknowns (which is determined by the equation and harmonic number). Thus increasing oversample is an effective way to improve accuracy without using too much memory as increasing harmonic number.An application where one would want to use oversample is on the LO of a mixer, because it is a strongly nonlinear signal in need of more samples in time-domain for an accurate Fourier Transformation.
For more information, similar tips, and design topics, please visit sourcelink.cadence.com.
Hi eliav zipper,
It's difficult to say what your issue might be. I strongly recommend filing a Service Request at sourcelink.cadence.com so I or one of my colleagues can delve into this further and assist you.
Is this relevant to PSS simulation ?
I tried it and was disappointed:
I just tried it on an LNA+mixer chain , and reducing PSS harmonics from 31 to 15, no matter how much over-sample I used, yielded odd rapid IP3 results (i.e. way off any logical value). Gain and Pnoise still looks the same, but that is no comfort.
This is a single tone PSS (the LO frequency).