polar impulse
| track circuit
| polar impulse | |
| tech. | 极性脉冲 |
| track circuit | |
| commun. railw. од. | 轨道电路 |
| el. | 示踪电路; 轨道回路; 跟踪电路 |
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| 极性脉冲 | |||
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polar impulse : 4 phrases in 2 subjects |
| Communications | 2 |
| Technology | 2 |