| 摘要 |
PROBLEM TO BE SOLVED: To prevent a reference signal for measurement from being erroneously transmitted in place of program signal. SOLUTION: When a program signal S1 is inputted, level fluctuation is detected by a level fluctuation detection circuit 1, and since a low-level signal is inputted to an AND circuit 2, an output is turned to low level and the program signal S1 is transmitted through a transmitter 4 and an antenna 5 without changing over a switching circuit 3. When the program signal S1 is not inputted, on the other hand, since no level fluctuation is detected by the level fluctuation detection circuit 1, a high-level signal is inputted to the AND circuit 2, the output is turned to high level, and a reference signal S5 for measurement is transmitted while changing over the switching circuit 3. |
