Active Probe Pod Signal Integrity for Logic Analyzers
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Solution Overview
Problem
Traditional logic analyzers using passive probe pods face signal attenuation and reflection issues due to long-distance signal transmission, leading to data loss and poor signal quality when capturing weak signals from DUT circuit boards.
Innovation Solution
An active probe pod with a front-end circuit board that converts weak signal inputs into LVDS differential signals, minimizing signal transmission distance and interference, and directly outputting these signals to an LVDS differential wire for transmission to the FPGA decoder, thereby reducing signal reflection and attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If weak signal input is transmitted over a long-distance single-end wire, then the signal can reach the operational amplifier and comparator, but the signal quality deteriorates due to attenuation and reflection
Solution Approach 1:
The patent introduces an active probe pod as an intermediary device between the DUT circuit board and the logic analyzer. This active probe pod includes a buffer amplifier that receives the weak signal from the DUT board and converts it to an LVDS differential signal, thereby mediating the signal transmission and avoiding direct long-distance transmission of the weak single-end signal which would cause attenuation and reflection
Solution Approach 2:
The patent changes the signal transmission parameters by converting the single-end weak signal into an LVDS differential signal. This parameter change includes transforming the signal type (from single-end to differential), changing the impedance characteristics, and improving the signal's immunity to interference during transmission, thereby resolving the attenuation and reflection issues
2Device complexity
If passive probe pod with single-end wire is used, then device complexity is reduced, but signal reflection and attenuation occur leading to data loss
Solution Approach 1:
The active probe pod acts as an intermediary that actively processes the signal before transmission. It includes a buffer amplifier that converts the single-end signal to LVDS differential signal, thereby preventing data loss from reflection and attenuation without significantly increasing overall system complexity
Solution Approach 2:
The patent replaces the passive mechanical/electrical transmission system (single-end wire) with an active signal processing system (LVDS differential transmission). This substitution uses active electronic components to actively manage signal integrity rather than relying solely on passive transmission media
3Adaptability or versatility
If weak signal is transmitted over long-distance path, then all channels can be detected, but signal attenuation negatively affects amplification and decoding
Solution Approach 1:
The active probe pod performs preliminary signal conditioning and conversion before the signal enters the long-distance transmission path. The buffer amplifier converts the weak single-end signal to a robust LVDS differential signal in advance, ensuring that the signal maintains its integrity throughout transmission and during subsequent amplification and decoding processes
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 approach enhances signal quality by minimizing signal reflection and attenuation, ensuring reliable data decoding with improved fidelity and reduced data loss, even at higher frequencies, and is applicable for both high-frequency and low-frequency signal measurements.
Implementation Method 1
the front-end circuit board may be implemented in terms of an LVDS IC or a comparator... amplifying the weak signal input into the corresponding LVDS differential signal
Implementation Method 2
The LVDS differential wire component may be electrically connected with the FPGA decoder... transmitting the LVDS differential LVDS signal to the FPGA decoder
Data Source
AI summary
An active probe pod used in a logic analyzer is disclosed. The active probe pod may be connected to the logic analyzer having a FPGA decoder and to a DUT circuit board. The active probe pod may include a LVDS differential ire component connected to the FPGA decoder and a front-end circuit board for capturing a weak signal input from the DUT circuit board. The front-end circuit board is adapted not to transmit the captured weak signal input over a long-distance signal transmission path, which helps minimize interferences with the weak signal input, while outputting a LVDS differential signal to the FPGA decoder for decoding. As the front-end circuit board is used for capturing the weak signal input, which falls within the category of one short-distance signal transmission, the signal reflection may not take place, without affecting the signal quality and/or attenuating the signal strength.