Crosstalk Induced Jitter Analysis Using Precomputed Lookup Tables
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Solution Overview
Problem
Analyzing and diagnosing crosstalk-induced jitter, particularly power supply-induced jitter (PSIJ), in electronic devices is challenging due to its non-linear and time-variant nature, making it difficult to accurately model and simulate, and existing methods are either time-consuming or require expensive equipment.
Innovation Solution
A method involving a measurement instrument that captures samples of aggressor and victim signals, applies them to a predetermined model to produce a system of equations, and ascertains unknown parameters to estimate and remove jitter, using ISI and crosstalk filter functions to separate and correct the victim signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If circuit simulation is used to analyze PSIJ, then analysis can be performed without expensive equipment, but the analysis is time-consuming and accuracy is limited due to model complexities
Solution Approach 1:
The patent pre-calculates and stores crosstalk coupling coefficients and transfer impedance values during an initialization phase, creating lookup tables that can be quickly queried during actual jitter analysis. This preliminary computation of coupling matrices and impedance parameters eliminates the need for time-consuming simulations during production testing, allowing rapid PSIJ estimation using simple formulas with pre-computed parameters.
2Measurement precision
If accurate circuit modeling is performed to improve PSIJ analysis accuracy, then measurement precision improves, but device complexity and analysis time increase
Solution Approach 1:
The patent divides the complex PSIJ analysis into separate independent components: crosstalk coupling coefficients between signal lines are calculated separately from power supply transfer impedance, and each is stored in dedicated lookup tables. The total jitter is then computed by combining these pre-calculated components using simple formulas. This segmentation allows accurate modeling of each mechanism without requiring a monolithic complex simulation model.
Solution Approach 2:
The patent transforms the complex dynamic simulation problem into a static lookup table query problem by pre-computing coupling coefficients and impedance values across the full operating range. During actual analysis, the system simply retrieves pre-stored parameters based on operating conditions and combines them using closed-form equations, eliminating the need for complex real-time simulations while maintaining accuracy.
3Measurement precision
If detailed circuit modeling is performed to capture non-linearities and parasitic impedances, then measurement precision improves, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent enables the measurement system to automatically extract all necessary parameters (crosstalk coupling coefficients, transfer impedance values, signal line characteristics) directly from the device under test through automated probing and measurement. The system self-calibrates by measuring actual device behavior and populating lookup tables with empirically-derived parameters, eliminating the need for manual model construction or external specification inputs. This automated self-characterization simplifies the measurement process while capturing real device non-linearities and parasitics.
Data Source
AI summary
A measurement instrument and associated method: receive at a first input an aggressor signal (e.g., a supply voltage) from a device under test (DUT); capture samples of the aggressor signal; receive at a second input a victim signal from the DUT, wherein the received victim signal includes jitter induced thereon from the aggressor signal; capture samples of the received victim signal; apply the captured samples of the aggressor signal and the captured samples of the received victim signal to a predetermined model, which represents the jitter induced onto the received victim signal from the aggressor signal, to produce a system of equations; ascertain a plurality of unknown parameters in the predetermined model from the system of equations; and apply the predetermined model with the ascertained parameters to the captured samples of the aggressor signal to estimate the jitter induced onto the received victim signal from the aggressor signal.