Baseband signal generator for digital modulator

The baseband signal generator for a digital modulator, comprising:

• means for supplying a digital baseband signal,
• means for performing a differential encoding processing and a mapping processing for said digital baseband signal to convert the signal into a plurality of symbol mapping data of different phases,
• a plurality of digital filtering means for limiting respective bandwidths of said plurality of symbol mapping data,
• means for designating burst transmission,
• each of said plurality of digital filtering means including:
• means for accumulating said symbol mapping data by the amount corresponding to a plurality of symbol sections,
• a plurality of read only memory means provided corresponding to said plurality of symbol sections for storing symbol data read out corresponding to a predetermined filter waveform,
• output masking means for selectively rendering said symbol data read out from said plurality of read only memory means to "0",
• mask controlling means responsive to a designation of burst transmission by said burst transmission designating means for controlling said output masking means in a predetermined timing, and
• means for adding the symbol data read out from said plurality of read only memory means, and
• a plurality of converting means for converting outputs of said plurality of digital filtering means into analog baseband signals.