NxS Stability Analysis: Beyond Probe-Based RFStability
NxS Stability Analysis: Beyond Probe-Based RFStability
MAXDI INC
Cognitave Inc (Subsidiary)
2025
Summary
NxS (Nonlinear eXtended Stability) assesses stability as an intrinsic property of the executed design-
flow graph. Unlike probe-driven methods (e.g., ADS WS-Probe), NxS evaluates the Jacobian of
the graph execution operator and derives deterministic stability metrics.
1 WS-Probe Paradigm
Probe-based approaches inject auxiliary signals and infer stability from observed behavior. This
procedure can be sensitive to probe placement and simulator semantics.
2 NxS Operator
Let the executed system be represented by an operator E(x; θ). NxS computes:
S_{NxS} =
∂E/∂x| x=x*.
Stability is indicated when the dominant real eigenvalue of SNxS remains negative.
3 RF Interpretation
In RF systems, NxS stability regions reduce to familiar impedance-based criteria and may be
visualized on a Smith chart. The key difference is causal traceability and deterministic execution.
4 Extension to Inference
Because NxS operates on the system graph, the same machinery extends to inference layers and
MXD disk embeddings, enabling unified stability analysis across physical and abstract domains.
IP © 2025 MAXDI INC. All rights reserved.
1 NxS Stability Analysis: Beyond Probe-Based RFStability >>
