发明授权
- 专利标题: Modulation device
- 专利标题(中): 调制装置
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申请号: US85189申请日: 1987-08-14
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公开(公告)号: US4794458A公开(公告)日: 1988-12-27
- 发明人: Akihiko Nagatomi
- 申请人: Akihiko Nagatomi
- 申请人地址: JPX Hamazaki
- 专利权人: DX Antenna Company, Ltd.
- 当前专利权人: DX Antenna Company, Ltd.
- 当前专利权人地址: JPX Hamazaki
- 优先权: JPX61-199341 19860825
- 主分类号: H03F1/00
- IPC分类号: H03F1/00 ; H04N5/40 ; H04N5/38
摘要:
A modulation device especially suitable for use in a joint TV reception device for tuning the input video and audio signals to various TV channel frequencies. The device includes a modulator for modulating a carrier wave with the video and audio signals to provide a modulated signal, a mixer for mixing the modulated signal with a local oscillation signal to provide mixed signals, a wide band amplifier for amplifying the mixed signals and a variable low-pass filter for filtering the amplified mixed signals to provide a TV broadcasting signal of desired frequency. The device further includes a control device for controlling the frequency of the local oscillation signal and the cutoff frequency of the variable low-pass filter so as to cancel a higher harmonic component from the output signal to avoid undesirable inteference.
公开/授权文献
- USD414381S Vacuum sealed canister set 公开/授权日:1999-09-28