康耀军, 李建国. ZPW-2000移频信号检测实验仪的设计与实现[J]. 实验科学与技术, 2024, 22(1): 131-137. DOI: 10.12179/1672-4550.20220226
引用本文: 康耀军, 李建国. ZPW-2000移频信号检测实验仪的设计与实现[J]. 实验科学与技术, 2024, 22(1): 131-137. DOI: 10.12179/1672-4550.20220226
KANG Yaojun, LI Jianguo. Design and Implementation of ZPW-2000 Frequency Shift Signal Coding and Detection Instrument[J]. Experiment Science and Technology, 2024, 22(1): 131-137. DOI: 10.12179/1672-4550.20220226
Citation: KANG Yaojun, LI Jianguo. Design and Implementation of ZPW-2000 Frequency Shift Signal Coding and Detection Instrument[J]. Experiment Science and Technology, 2024, 22(1): 131-137. DOI: 10.12179/1672-4550.20220226

ZPW-2000移频信号检测实验仪的设计与实现

Design and Implementation of ZPW-2000 Frequency Shift Signal Coding and Detection Instrument

  • 摘要: 依据周期测频法设计了以FPGA为核心器件的ZPW-2000移频信号检测实验仪。该实验仪采用8个计数器实现移频信息的检测,其中,边频检测采用2个计数器分别检测计数信号上下跳沿,通过选择2组计数值中较大值,使计数误差降低至0-1个计数信号周期,在200 MHz计数信号下,边频检测误差可控制在0.07 Hz以内;低频检测采用6个异步计数器,分别实现移频信号中低频成分的获取及低频频率的检测计算,低频频率计数器通过设置前N个状态进行低频计数,第N+1个状态进行计数值锁存分析的方式,有效降低了低频获取引起的误差。分析发现,当N≥10时,最大误差可降至0.029 Hz以下。实验仪实测证明,边频、低频检测误差均能满足铁道标准TB/T 3532—2018中移频信号上下边频误差±0.15 Hz、低频误差±0.03 Hz的要求;检测实验仪能准确解算出基于FPGA的ZPW-2000移频信号发码实验仪移频信息,解决了ZPW-2000系列轨道电路移频信号教学及实验任务必须采用铁路专用设备的限制,结合发码实验仪可为学生更直观地展示轨道电路发码与检测过程,使学生更加深入地了解移频轨道的电路原理。

     

    Abstract: A signal detection experimental equipment using the ZPW-2000 frequency shift signal detection method is designed, which is based on the cycle frequency measurement method. The experimental track circuit frequency shift signal detection apparatus has an field programmable gate array(FPGA) at its core. The side frequency detection method uses two counters to detect the upper and lower jumping edges of the counting signal, and the counting error is reduced to 0-1 counting signal cycle by choosing the larger value of the two sets of counting values. The side frequency detection error can be controlled within 0.07 Hz under the counting signal of 200 MHz. The detection method uses eight counters to realize the detection of shifted frequency information. In order to achieve the acquisition of low-frequency components in the frequency-shifted signal as well as the detection and calculation of low-frequency frequency, the low-frequency detection employs six asynchronous counters, respectively. The experimental instrument measurement demonstrates that the side frequency and low-frequency detection error can meet the requirements of the railway standard TB/T 3532—2018 in the frequency shifted signal up and down the side frequency error of ±0.15 Hz and low-frequency error of ±0.03 Hz. The experimental instrument can accurately calculate the shifted frequency information, which is based on the FPGA ZPW-2000 frequency shifted signal generator. The experimental equipment breaks the limitations of specialized equipment in teaching and experiment, and help students better understand how track circuits are coded and detected.

     

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