| 摘要 |
PURPOSE:To analyze the transmission characteristics of a transmission system to be measured with high accuracy, by comparing the frequency spectrum distributions of received converted output signals through a standard transmission system and the transmission system, wherein a test signal, whose carrier wave is modulated with a modulating signal having a specified signal waveform, is made to pass. CONSTITUTION:The output side of a broadcasting unit 5a is terminated with a dummy resistor 7a. Under this state, a modulated test signal undergoes A/D conversion. The digital data are analyzed through high speed Fourier transformation, and frequency spectrum distribution F(omega) is obtained. Then, e.g., the output terminal of the currently operating broadcasting unit 5a is connected to a matching circuit and antenna 6a. The modulated test signal, which is transmitted from the antenna, is received by a standard receiving antenna 6b, whose characteristics are known. Under this state, the similar frequency spectrum distribution G(omega) is obtained. The overall transmission characteristic H(omega) of the transmission system from the broadcasting unit 5a to the standard receiving antenna 6b is obtained by an expression I, where the characteristic of the standard receiving antenna 6b is I(omega), based on both distributions F(omega) and G(omega). |
