Amplitude modulation system |
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| 申请号 | JP12009879 | 申请日 | 1979-09-20 | 公开(公告)号 | JPS5644206A | 公开(公告)日 | 1981-04-23 |
| 申请人 | Oki Electric Ind Co Ltd; | 发明人 | YOSHIDA TETSUO; | ||||
| 摘要 | PURPOSE:To make high-efficiency and linear modulation possible, by amplifying two-phase modulation signals shifted by + or -DELTAphi and a nonmodulation signal different from the carrier wave in phase by 90 deg. by switching power amplfiers. CONSTITUTION:After the carrier signal is modulated into signals having the phase inverted mutually by phase modulating circuit 52, they are subjected to + or -theta phase modulation by the sound signal. Then, phase modulating circuit 52 outputs +phi and pi-phi phase modulation signals. Phase modulation waves phi and pi-phi modulated in directions opposite to each other are amplified by switching amplifiers 53 and 54, and these outputs are synthesized with a signal different from the carrier wave for nonmodulation in phase by pi/2. This output is taken out from matching circuit 58, thereby realizing a good modulation characteristic for the input signal. | ||||||
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| 说明书全文 | |||||||
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