Frequency modulator in common use for both analog and digital signals |
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| 申请号 | JP19281689 | 申请日 | 1989-07-27 | 公开(公告)号 | JPH0276405A | 公开(公告)日 | 1990-03-15 |
| 申请人 | Nokia Mobira Oy; | 发明人 | ERUTSUKI JIYUHANI KUISUMA; | ||||
| 摘要 | PURPOSE: To attain frequency modulation using both analog / digital signals by selecting an analog signal or a digital signal for a modulation signal in the case of modulating a radio transmission frequency signal with a base band signal. CONSTITUTION: When couplers K1, K2 are set to a position (d), digital frequency modulation, that is, signals ID, QD are selected, and when the couplers K1, K2 are set to a position (a), analog frequency modulation, that is, signals IA, QA are selected. The selected I, Q signals are mixed with an intermediate frequency signal at an intermediate frequency stage 3, the result of mixing in the intermediate frequency stages 3 is summed and the result is sent to a high frequency stage 4, in which the result is mixed with a transmission frequency signal. Thus, the frequency modulation for analog/digital is conducted. COPYRIGHT: (C)1990,JPO |
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