| 摘要 |
<p>A radio communication system and apparatus are provided to increase productivity of a keyless entry system by removing such a process of installing a resistor on a circuit board. A first radio communication device includes a CPU, a memory, a transmitter for transmitting a first radio signal, and a receiver for receiving a second radio signal. A second radio communication device includes a CPU, a memory, a transmitter for transmitting the second radio signal, a receiver for receiving the first radio signal, and a signal intensity measurement unit for measuring the intensity of the first radio signal. The first radio communication device transmits the first radio signal. The second radio communication device receives the first radio signal. The second radio communication device measures the intensity of the first radio signal. The second radio communication device transmits the second radio signal containing the signal intensity. The first radio communication device receives the second radio signal. The first radio communication device stores a threshold value in order to compare the threshold value with the signal intensity. The first radio communication device compares the signal intensity included in the received second radio signal with the threshold value in order to determine the distance between the first radio communication device and the second radio communication device.</p> |
