| 摘要 |
PROBLEM TO BE SOLVED: To improve the S/N by providing a threshold level filter that limits an output power level at each frequency within a spread signal frequency band so as to set a transmission power to the maximum level of a regulation thereby increasing the transmission power. SOLUTION: A spread high frequency f3 is amplified up to a saturation level of a static magnetic wave filter 8a. Then an output level of the filter 8a is limited to about -30dB. This limit level on the frequency axis indicates that power at all frequencies is uniformly limited by the saturation level of the filter 8a. Then the frequency band of the spread high frequency f3 is limited within the frequency band stipulated by the regulation at a next stage band-pass filter 9. Then the spread high frequency f3 is amplified in the vicinity of a stipulated power by the Radio Wave Law by a power amplifier 10 and the frequency signal is sent from an antenna 11. |
