| 摘要 |
Unwanted transmitter modulation which would otherwise have an undesirable impact at a radio receiving the transmitted signal is detected and cancelled. The radio transmitter includes a phase-locked loop that receives an input signal and a feedback signal. An amplifier stage amplifies an output from the phase-locked loop, and an antenna transmits the amplified signal. A detector detects the transmitted signal and generates the feedback signal. Inclusion of the amplifier stage in the phase-locked loop compensates for undesirable transmitter modulation introduced at the amplifier stage. One example application of the present invention is to vehicular-based radio systems, where the radio transmitter is susceptible to the noise generated by the vehicle electrical system which ultimately results in an audible whine at the radio receiver. The whine heard at the receiver is greatly reduced/eliminated. |
