| 摘要 |
<p>PURPOSE:To obtain a filter characteristic in accordance with prearranged plan without regulation by forming filters of two systems different in their central frequencies at which signals are passed of ceramic respectively. CONSTITUTION:A transmitting and receiving device has a first system which is formed of directly connecting ceramic filters 5, 7, amplifiers 6, 8, a log ampli fier 9 and a waveform shaper 10 connected to a receiving antenna 2 and a second system which is formed of directly connecting ceramic filters 12, 14, amplifiers 13, 15, a log amplifier 16 and waveform shaper 17 connected to the antenna 2. The filters of two systems mainly passes a frequency component corresponding to a central frequency in analog signals obtained by receiving wireless information respectively. A receiver from these components generates digital signals in accordance with the wireless information, and according to the signals the system performs production management. A filter characteristic can be obtained in accordance with a prearranged plan without regulation by forming each filter made of ceramic.</p> |
