发明名称 |
Refined tuning of RF receiver with frequency-locked loop |
摘要 |
In an RF receiver having a phase-locked loop demodulator and FLL tuning in its RF converter, the frequency of the VCO output signal in the phase-locked loop (PLL) demodulator is controlled indirectly by the FLL in the RF converter in response to a measurement of the VCO output signal in the phase-locked loop demodulator and comparison of such measured signal to a predetermined intermediated frequency. A microcomputer performs a refined FLL tuning algorithm to tune a selected RF carrier input signal and audio subcarrier input signals. The algorithm provides a means of assuring that the PLL demodulator is responding to an input signal derived from a carrier signal of a selected input frequency without having to use hardware to detect the presence of a carrier signal.
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申请公布号 |
US4823399(A) |
申请公布日期 |
1989.04.18 |
申请号 |
US19870080412 |
申请日期 |
1987.07.30 |
申请人 |
GENERAL INSTRUMENT CORPORATION |
发明人 |
GEORGE, ASHOK K. |
分类号 |
H03D3/24;(IPC1-7):H03D7/16;H03J7/04;H04N5/50 |
主分类号 |
H03D3/24 |
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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