发明名称 |
Adaptive wideband AFC system |
摘要 |
Circuitry compensating for inherent nonlinearities in the tuning voltage sensitivity of varactor tuners, thereby providing relatively constant AFC pull-in range throughout the band of operating frequencies, is shown. In both the VHF and UHF bands, the AFC system develops an error correction voltage in proportion to the tuning voltage. With respect to reception of VHF channels, a gain switching circuit operates to reduce the proportion of AFC error correction voltage developed on a High Band VHF channel, thereby compensating for increased tuning voltage sensitivity on High Band VHF. With respect to reception of UHF channels, a tuning voltage sensing circuit operates to effect an error correction voltage that is a greater proportion of the tuning voltage when the tuning voltage is above a pre-determined value corresponding to approximately channel 60.
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申请公布号 |
US4122493(A) |
申请公布日期 |
1978.10.24 |
申请号 |
US19770833759 |
申请日期 |
1977.09.16 |
申请人 |
GTE SYLVANIA INCORPORATED |
发明人 |
ARUMUGHAM, RANGASWAMY;KAM, GEORGE HAGER |
分类号 |
H03J7/10;H04N5/50;(IPC1-7):H04N5/50;H04B1/16 |
主分类号 |
H03J7/10 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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