| 摘要 |
A RADIO-FREQUENCY APPARATUS HAVING A RADIO-FREQUENCY MODULATOR (1) AND A TELEVISION TUNER (2) IS DESIGNED SO AS TO REDUCE THE MANUFACTURING COST BY REDUCING THE NUMBER OF CRYSTAL RESONATORS AND SO AS TO PREVENT BEAT INTERFERENCE. A RADIO-FREQUENCY MODULATOR AND A TELEVISION TUNER ARE PROVIDED IN A SHIELD CASE (34) WHILE BEING SEPARATED FROM EACH OTHER BY A SHIELD PLATE (35). ONE CRYSTAL RESONATOR (13) IS USED IN COMMON FOR A FIRST REFERENCE OSCILLATOR (14) OF THE RADIO-FREQUENCY MODULATOR AND A SECOND REFERENCE OSCILLATOR (24) OF THE TELEVISION TUNER TO SET A RESONANT FREQUENCY OF EACH OF THE FIRST AND SECOND REFERENCE OSCILLATORS. ON A PRINTED CIRCUIT BOARD ON WHICH THE RADIOFREQUENCY MODULATOR (1) AND THE TELEVISION TUNER (2) ARE PROVIDED, A LOWPASS FILTER (25) IS DISPOSED ON THE TELEVISION TUNER SIDE AND IN THE VICINITY OF THE SHIELD PLATE (35) WHILE THE CRYSTAL RESONATOR (13) IS DISPOSED ON THE RADIO- FREQUENCY MODULATOR SIDE AND IN THE VICINITY OF THE FIRST REFERENCE OSCILLATOR (14).THE CRYSTAL RESONATOR (13) IS CONNECTED TO THE FIRST REFERENCE OSCILLATOR (14) AND IS ALSO CONNECTED TO THE SECOND REFERENCE OSCILLATOR (24) VIA THE LOWPASS FILTER (25).(FIG 1)
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