发明申请
US20110009161A1 USING LO SHIFTING TO PREVENT A LOCAL TRANSCEIVER FROM INTERFERING WITH AN FM RADIO 有权
使用自动转换功能防止本地收发器与FM无线电干扰

USING LO SHIFTING TO PREVENT A LOCAL TRANSCEIVER FROM INTERFERING WITH AN FM RADIO
摘要:
A cellular telephone includes cellular telephone circuitry and an FM receiver. An FM signal being received is downconverted by a mixer. The downconverted signal is processed to generate an FM signal that is supplied to a digital IF filter. If a blocker emitted by the cellular telephone circuitry would interfere with receiving of the FM signal due to interaction of an LO harmonic with the blocker if a conventional LO frequency were used, then a different LO frequency is used. Subsequent processing of the downconverted FM signal (for example, by a digital complex conjugate selector and an IF rotator) results in the signal supplied to the digital IF filter having the same center frequency as the digital IF filter despite the use of the different LO frequency. In some embodiments, the LO is shifted by different amounts depending on cellular telephone mode and on the FM signal.
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