| 摘要 |
PURPOSE:To output a modulation signal without changing the condition of waveform shaping and to apply monolithic circuit integration to an orthogonal modulator by using a MOSFET analog filter whose frequency characteristic is variable. CONSTITUTION:An input signal is inputted to a digital signal processing circuit 2 via a switch 11, two series of digital signals whose output phases are intersected orthogonally with each other are D/A-converted 3 respectively, the result is inputted to each multiplier 7 via a MOSFET analog filter 12, the signal is multiplied with each carrier whose phases are intersected orthogonally with each other, multiplication outputs are added 8 and outputted. In this case, the frequency characteristic of each LPF 12 is made variable by using the clock signal of the signal inputted to the processing circuit 2 and the harmonic component of the output signal of the converter 3 is removed. |
