发明名称 |
Phase locked loop tuning system with station scanning provisions |
摘要 |
A tuning system for a television receiver includes a first phase locked loop configuration for controlling the frequency of the receiver's local oscillator signal in accordance with the number of the channel presently being tuned and a second phase locked loop configuration for controlling the frequency of the local oscillator signal to reduce any frequency deviation between the receiver's IF picture carrier and 45.75 MHz corresponding to a frequency offset between the associated RF carrier and the standard RF carrier frequency for the channel being presently tuned due to the frequency translation provided by a television distribution system. The tuning system includes control units for automatically changing the channel number and selectively enabling the operation of the first and second phase locked loop configuration in accordance with a tuning algorithm so that active channels may be automatically located and tuned while preventing the receiver from being erroneously tuned to undesirable signals.
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申请公布号 |
US4077008(A) |
申请公布日期 |
1978.02.28 |
申请号 |
US19760733673 |
申请日期 |
1976.10.18 |
申请人 |
RCA CORPORATION |
发明人 |
RAST, ROBERT MORGAN;TULTS, JURI |
分类号 |
H03J5/02;H03J7/28;(IPC1-7):H04B1/16 |
主分类号 |
H03J5/02 |
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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