| 摘要 |
PURPOSE: To provide a baseband signal generator for multi-level superposed amplitude modulation with a simple structure, a band width with a limit effect and good power efficiency in a digital transmission system and to provide a baseband signal of multi-level superimposed amplitude modulation that has provision for revision of number of multi-level through simple revision of devices, when number of the multi-level is changed, especially while avoiding complicated circuits. CONSTITUTION: This generator is made up of a data delay section 2 that delays k-bit data by one symbol period, a signal level conversion section 1 that converts the signal level into 2<k> levels in a multi-level superimposed amplitude modulation signal space, an arithmetic section 3 that operates a control signal of each section for one symbol period, two pulse generating means 4-6, 9-11 that generate a pulse corresponding to cos(πt/T) and cos(2πt/T), two amplifiers 7, 12 that amplify the generated pulse corresponding to the control signal, and two adders 8, 13 that add or subtract the control signal and an output of the amplifiers. |
