| 摘要 |
PURPOSE: To simplify the constitution of a circuit, to reduce an oscillator and to reduce a spurious component by sharing a local oscillation circuit for orthogonal detection, a second mixer and a mixer for orthogonal detection. CONSTITUTION: A mode at the time of digital output and a mode at the time of analog output are switched by adding a switching signal S to the selection of an oscillator 34. At the time of digital output, the oscillator 34 directly supplies the frequency signal of 961MHz to the mixers 33 and 32 or through a phase shifter 35, and transmits an I-signal to a terminal 38 and a Q-signal to a terminal 39. When I/Q output is obtained as digital output, the outputs of the mixers 32 and 33 for orthogonal detection are branched and outputted to the terminals 38 and 39 through low pass filters 36 and 37. At the time of analog output, the oscillator 34 supplies the frequency signal of 916MHz to the mixer 33 and analog output changing with a frequency 45MHz as a center to a terminal 40 as second intermediate frequency output. Thus, the orthogonal detection local oscillation circuit and the second mixer are shared for the mixer for orthogonal mixer and the constitution of the circuit becomes simple. |
