| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the occurrence of the limiting errors of a communication area caused by the unbalance of gains of two receivers by preparing a level corrector which corrects the output level of a 2nd receiver, a temperature detector which detects the internal temperatures of devices and a ROM which receives the temperature information from the temperature detector and outputs a control signal to the level corrector. SOLUTION: A 1st receiving antenna 11 has directivity and a 2nd receiving antenna 12 has a pattern that is different from the pattern of the antenna 11. Meanwhile, a 1st receiver 13 receives the output of the antenna 11 to amplify and filter it and converts the frequency, etc., and a 2nd receiver 14 receives the output of the antenna 12 and amplifies and filters it and converts the frequency, etc. Then a temperature detector 24 detects the internal temperature of a road side communication device 4 and outputs temperature information 25. A ROM 26 receives the information 25 and outputs a control signal to a level corrector 23. The corrector 23 corrects the unbalance of gains due to the different temperatures of both receivers 13 and 14. Thus, limiting a communication area limited with high precision is made available.</p> |
