| 摘要 |
A signal receiver apparatus of a railway signal system is provided to receive a signal within an optimum sensitivity band by changing reception sensitivity. An input transformer(30) interfaces a frequency in order to minimize loss of a signal by matching impedance between a track rail and a receiver apparatus. A high pass filter(32) is formed at a secondary side of the input transformer in order to pass only a high frequency and to block a low frequency. A low pass filter(34) is formed at the secondary side of the input transformer in order to pass the low frequency and to block the high frequency. An amplifier(36,42) amplifies the signal outputted from the high pass filter and the low pass filter. A filter(38,44) is connected to an output terminal of the amplifier in order to filter the noise signal from the output signal of the amplifier. A demodulation unit(40,46) performs a pulse code modulation process by modulating the frequency signal. An AND gate(48) performs a logical operation according to a pulse signal. A delay unit(50) is connected to an output part of the AND gate in order to perform a signal delay process. A relay driver(52) is connected to an output terminal of the delay unit in order to control the power according to the pulse signal. A display control unit(54) controls on/off states of LED(Light-Emitting Diode)s of a display panel. |
