| 摘要 |
PURPOSE: An apparatus for canceling an LOF(Local Oscillator Frequency) in a transmission and reception up/down converter is provided to prevent the output of an LOF with a high level by adjusting and converting the phase of the LOF and canceling the LOF. CONSTITUTION: An LO(Local Oscillator)(20) generates an assigned LOF, and outputs the generated LOF. A splitter(30) splits the signal outputted from the LO(20) into signals with the same level, and outputs the split signals through two paths respectively. A mixer(40) mixes the LOF outputted from one output end of the splitter(30) with an inputted IF(Intermediate Frequency), and outputs a signal modulated by an assigned frequency. A 90 degree phase shifter(50) shifts the phase of the LOF outputted from the other output end of the splitter(30) at 90 degrees, and outputs the shifted LOF. A phase adjusting circuit(60) shifts the phase of the signal outputted from the 90 degree phase shifter(50) at 90 degrees, accurately adjusts the phase shift of 180 degrees, and outputs the adjusted signal. A combiner(70) combines the signal outputted from the mixer(40) with the signal outputted from the phase adjusting circuit(60) to cancel the LOF, and outputs only a modulated frequency signal. |
