| 摘要 |
<p>PROBLEM TO BE SOLVED: To use a local oscillation circuit in common. SOLUTION: A frequency synthesizer 105 generates a 1st local oscillation frequency for orthogonal transformation and a 2nd local oscillation frequency in the case of analog reception based on a control signal from a changeover control section 300. An orthogonal demodulation circuit including multipliers 103, 104 of a digital IF section 100 is active in the digital mode and a reception wave from a high frequency section is orthogonally transformed and the result is fed to a base band processing section. In the analog mode, a buffer 109 gets through and the 2nd local oscillation frequency is fed to an analog IF section. Similarly, a modulation section 200 uses a frequency synthesizer 206 to generate a 3rd local oscillation frequency for orthogonal modulation to drive the orthogonal modulation circuit such as multipliers 204, 205. In the case of analog signal transmission, a frequency synthesizer 105 generates a 4th local oscillation frequency and it is frequency-modulated by an analog modulation signal and the result is outputted to a high frequency stage via the multiplier 205.</p> |
