PET Detector Optical Synchronization Circuit
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Solution Overview
Problem
Current PET systems employing solid state detectors face challenges with synchronization due to the use of galvanic cables, which increase size and cost, and optical transceivers introduce high power consumption and poor jitter, making them undesirable for time-of-flight PET applications.
Innovation Solution
The implementation of an optical transceiver system that receives an optical data stream with a pulse train, featuring synchronization circuitry to jitter-clean the pulse train and extract a jitter-clean sync/reset pulse for internal clock synchronization, reducing the need for galvanic connections and minimizing jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic cables are used to synchronize reference clocks in PET detectors, then synchronization can be achieved, but system size and cost increase
Solution Approach 1:
The patent replaces galvanic (electrical) cable connections with optical fiber connections for transmitting synchronization signals between detector modules. This substitution eliminates the need for physical electrical connectors and reduces system complexity while maintaining synchronization accuracy through optical signal transmission.
Solution Approach 2:
The patent extracts the synchronization function from the data transmission path by implementing a separate dedicated synchronization signal transmission channel. This allows synchronization signals to be transmitted independently from data signals, enabling the use of simpler optical connections without interfering with data acquisition operations.
2Device complexity
If optical transceivers are used for synchronization, then galvanic connections are reduced, but power consumption increases and jitter performance deteriorates
Solution Approach 1:
The patent employs cost-effective optical transceiver components that are optimized for synchronization signal transmission rather than high-speed data transmission. These components accept higher jitter characteristics in exchange for reduced cost and power consumption, which is acceptable for synchronization signals that do not require the same timing precision as data transmission.
Solution Approach 2:
The patent implements different transmission quality requirements for different signal types: high-precision low-jitter transmission for data signals and acceptable-jitter low-power transmission for synchronization signals. This local quality differentiation allows the system to optimize each channel for its specific requirements rather than over-engineering all channels to the highest specification.
3Reliability
If optical transceivers are deployed extensively, then synchronization can be achieved without galvanic cables, but system cost and power consumption increase
Solution Approach 1:
The patent designs the optical transceiver system to handle both data transmission and synchronization signal transmission through integrated optical fiber infrastructure. By making the optical network universal for both purposes, the system eliminates the need for separate galvanic cable systems while optimizing transceiver usage to reduce overall power consumption.
Solution Approach 2:
The patent recovers and reuses the optical fiber infrastructure for dual purposes: data transmission and synchronization signal transmission. Instead of deploying separate dedicated optical channels for synchronization, the system utilizes the existing optical data transmission channels to carry both types of signals, thereby recovering infrastructure value and reducing redundant power consumption.
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 reduces system size and cost, minimizes galvanic connections, and provides low jitter clock signals and sync/reset pulses, enhancing synchronization accuracy in PET systems.
Implementation Method 1
an optical transceiver receiving an optical data stream from a PET processing system
Implementation Method 2
synchronization circuitry configured to simultaneously jitter clean the pulse train
Data Source
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AI summary
A detector module (50) for a positron emission tomography (PET) system (10) includes an optical transceiver (66) receiving an optical data stream from a PET processing system (48). The data stream includes a pulse train carrying a command to generate sync/reset pulses. The system (10) further includes synchronization circuitry (70) configured to simultaneously jitter clean the pulse train and one of: 1) count the pulses of the pulse train; and 2) monitor the pulse train for a missing pulse. The synchronization circuitry (70) is further configured to, in response to counting a predetermined number of pulses or detecting the missing pulse, extract a jitter clean pulse from the pulse train to generate a jitter clean sync/reset pulse. The system (10) further includes an internal clock (64) which receives the jitter clean sync/reset pulse.