Optical MUX for Test Instruments Reducing Signal Loss
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Solution Overview
Problem
Current test and measurement systems face challenges in efficiently measuring multiple signal lanes due to limited input channels, error-prone manual cable reconfiguration, and significant signal degradation caused by RF cables, especially at high frequencies, which complicates de-embedding and affects measurement accuracy.
Innovation Solution
The implementation of remote heads with electrical-to-optical modulators and optical interconnection circuitry allows for the conversion of electrical signals to optical signals, enabling remote placement of test equipment and reducing the need for de-embedding, while maintaining signal integrity and accuracy through optical multiplexing and compensation circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If RF cables are used to connect test equipment to DUT, then signal transmission is enabled, but signal degradation and insertion loss increase significantly at high frequencies
Solution Approach 1:
The patent replaces the mechanical/electrical RF cable connection system with an optical communication system. Electrical signals from the DUT are converted to optical signals for transmission over optical fibers, eliminating the high-frequency signal degradation and insertion loss associated with RF cables. This substitution maintains measurement accuracy while enabling longer cable lengths without de-embedding requirements.
2Adaptability or versatility
If manual cable reconfiguration is performed to test multiple signal lanes, then all lanes can be measured, but time and labor requirements increase significantly
Solution Approach 1:
The patent replaces manual mechanical cable reconfiguration with an automated optical multiplexer system. The multiplexer automatically switches between multiple optical input channels corresponding to different signal lanes, enabling seamless transition between lanes without manual intervention. This automation dramatically reduces testing time while maintaining the ability to measure all signal lanes.
Solution Approach 2:
The patent implements a universal test setup where a single test equipment configuration can measure multiple signal lanes through the optical multiplexer. The system provides multi-functionality by allowing one instrument to access multiple DUT lanes simultaneously or sequentially, eliminating the need for separate test configurations for each lane and significantly improving testing efficiency.
3Extent of automation
If RF switch matrix is used for automated lane switching, then cable reconfiguration is automated, but de-embedding becomes difficult and errors increase at high frequencies
Solution Approach 1:
The patent replaces the RF switch matrix with an optical switch or optical multiplexer in the optical domain. This substitution eliminates the de-embedding problems associated with RF switches at high frequencies, as optical switches do not introduce the same frequency-dependent signal degradation. The automation is preserved through electronic control of the optical switching mechanism while measurement precision is maintained.
4Reliability
If DUT is placed close to test equipment inputs, then signal integrity is maintained, but physical space requirements and setup complexity increase
Solution Approach 1:
The patent replaces direct electrical connections with optical fiber connections between the DUT and test equipment. Optical fibers can transmit signals over much longer distances without degradation compared to electrical cables, allowing the DUT to be positioned remotely from the test equipment. This reduces setup complexity and space requirements while maintaining signal integrity through the optical transmission medium.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables efficient testing of multiple signal lanes with reduced signal loss and noise, allowing for greater distances between test equipment and devices under test without compromising signal quality, thereby simplifying setup and improving measurement accuracy.
Implementation Method 1
each of the one or more remote heads including an electrical-to-optical modulator (EOM) configured to convert the received electrical test signal into an optical test signal
Implementation Method 2
the optical interconnection circuitry configured, in response to control signals, to select one of the optical test signals and to convert the selected optical test signal into an electrical test signal to be supplied to a test port of a test and measurement instrument
Data Source
AI summary
A test and measurement system includes one or more remote heads, each of the one or more remote heads configured to be coupled to a respective device under test (DUT) to receive an electrical test signal from the DUT and each of the one or more remote heads including an electrical-to-optical (EOM) configured to convert the received electrical test signal into an optical test signal. Optical interconnection circuitry receives the optical test signal from the EOM of the one or more remote heads and, in response to control signals, selects one of the optical test signals to be provided to a test and measurement system. The optical interconnection circuitry further converts the selected optical test signal into an electrical test signal to be supplied to a test port of the test and measurement instrument. Methods are also described.