| 摘要 |
<p>PURPOSE: To suppress lower and upper side bands by utilizing not an IF or RF remaining side band filter but a base band, i.e., reference band, filter system in a remaining side band/pulse amplitude modulation demodulator. CONSTITUTION: Three inputs 702, 704, 706 are inputted to a modulator 700, and when the modulator 700 is used as a quadrature amplitude modulator, a reference band in-phase channel signal is entered through the input 702 and a channel signal is entered through the input 706. Switches 708, 710 respectively send in-phase and quadrature phase channel reference band signals to in-phase and quadrature phase channel reference band filters 712, 714. When the modulator 700 is used for a remaining side band signal, these reference band signals are entered into the input 704, the input 704 is sent to both of an in-phase channel and a quadrature channel and the switches 708, 710 send the reference band signals to the filters 712, 714. Then the tap weight values of the filters 712, 714 are stored in a storage device 720.</p> |
