Jitter Measuring Apparatus Using Complementary Data Signal

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Solution Overview

Problem

Conventional methods are ineffective in accurately measuring timing jitter in data signals with irregular patterns due to high jitter in triggering signals and high costs associated with precision circuits, and lack real-time measurement capabilities.

Innovation Solution

A jitter measuring apparatus and method that utilize pulse generating sections to detect edges and boundaries in data signals, a complementary data signal to align edges at equal intervals, and a jitter calculating section with integrator and sample-and-hold circuits to calculate timing jitter based on pulse signals, enabling accurate and cost-effective measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods (sampling oscilloscope, digital oscilloscope) are used to measure jitter in data signals, then measurement capability is provided, but measurement precision deteriorates due to large timing jitter in triggering signals

Engineering Contradiction:

Improvetiming jitter measurement precisionVSAvoidtriggering signal timing stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a complementary data signal as an intermediary to bridge the gap between the data signal and the triggering signal. This complementary signal has edges at regular intervals that synchronize with the data signal boundaries, allowing the generation of triggering signals with stable timing without directly using the irregular data signal edges, thus resolving the contradiction between measurement capability and triggering signal stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the measurement process into multiple independent components: a complementary data signal generating section that creates a synchronized reference signal, a pulse generating section that creates measurement pulses based on this reference, and a jitter calculating section that processes the pulse timing differences. This segmentation allows each component to optimize its function independently, improving overall measurement precision while maintaining triggering signal stability

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If high-precision circuits are used to generate triggering signals with less timing jitter, then measurement precision improves, but manufacturing cost increases

Engineering Contradiction:

Improvetriggering signal timing precisionVSAvoidmeasuring cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent creates a copy of the data signal in the form of a complementary data signal that has regular timing intervals. This copy serves as a reference for generating triggering signals, eliminating the need for expensive high-precision circuits. The complementary signal is generated through simple logic operations (NOT gate and edge detection) rather than requiring precision hardware, thus improving measurement precision while reducing manufacturing cost

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent uses simple, low-cost logic circuits and signal processing techniques to generate the complementary data signal and triggering signals, replacing the need for expensive high-precision timing circuits. The solution employs standard digital logic components and algorithms that can be implemented cost-effectively, making high-precision jitter measurement accessible without requiring significant investment in specialized hardware

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If multiple triggering signals with various timings are generated to handle irregular data signal edges, then measurement coverage is improved, but device complexity increases

Engineering Contradiction:

Improvemeasurement coverage for irregular signalsVSAvoidtriggering signal generation complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal triggering signal generation mechanism that handles all types of data signal edges (rising and falling) through a single complementary data signal approach. The complementary signal automatically adapts to any data pattern by generating edges at regular intervals that synchronize with data boundaries, eliminating the need for multiple specialized triggering signals and reducing overall system complexity while maintaining broad measurement coverage

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7496137B2Apparatus for measuring jitter and method of measuring jitter

Publication Date: 2009.02.24 ADVANTEST CORP

AI summary

There is provided a jitter measuring apparatus for measuring jitter in a signal-under-measurement, including a pulse generating section having first pulse generating means for detecting edges of the data-signal-under-measurement to output a first pulse signal having a pulse width set in advance corresponding to the edge and second pulse generating means for detecting boundaries of data sections where data values do not change in the data-signal-under-measurement to output a second pulse signal having a pulse width set in advance over the edge timings of the boundaries of the detected data sections and a jitter calculating section for calculating timing jitter in the data-signal-under-measurement based on the first and second pulse signals.