| CPC G01R 31/14 (2013.01) | 9 Claims | 

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               1. A field-programmable gate array (FPGA) chip-based system for detecting a cable insulation state, comprising a detection card and a coupler; 
            wherein the detection card comprises an FPGA chip, and a first circuit and a second circuit that are connected to the FPGA chip; 
                wherein the FPGA chip comprises a logic control module and a detection signal generation module that are connected in series to the first circuit, and a synchronization module, a noise reduction module, a signal processing module and a state evaluation module that are connected in series to the second circuit; 
                wherein the synchronization module comprises a coarse synchronization correlation calculation module, a fine synchronization correlation calculation module and a data delay module; 
                wherein the coarse synchronization correlation calculation module is configured to calculate an energy of a reflection signal and an autocorrelation value, and the coarse synchronization correlation calculation module is connected to a first comparator; 
                the fine synchronization correlation calculation module is configured to calculate a cross-correlation value of the reflection signal and a training sequence in a read only memory (ROM) module, and the fine synchronization correlation calculation module is connected to a second comparator; 
                the first comparator and the second comparator are connected to a selector separately, and the selector is connected to a third comparator, 
                the data delay module is configured to perform delay on input signal data and use the delayed data as an input signal of a data interception module, and a delay duration is a data processing duration of the synchronization module; 
                the data interception module is configured to output a signal to the noise reduction module in response to an instruction signal sent by the third comparator; and 
                wherein the first circuit is configured to send a detection signal generated by the detection signal generation module to the coupler, the coupler is configured to: inject the detection signal into a to-be-detected cable connected to the coupler, extract the reflection signal from the to-be-detected cable and send the reflection signal to the state evaluation module through the second circuit to evaluate a state of the to-be-detected cable. 
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