Modulation method and circuit for time division multiple access

A modulation circuit for time division multiple access comprising:

• a first encoder and a second encoder for differentially encoding transmission data signals in the odd-numbered and even-numbered time-slots, respectively;
• a first and second shift register for converting the signals differentially encoded by said first and second encoders by means of applying a shift operation for the signals differentially encoded by said first and second encoders into parallel signal data;
• a selector for selecting a corresponding one of said parallel signal data in accordance with said odd-numbered or even-numbered time-slot;
• and,
• a ROM for reading each of the data of narrow-banded signal waveforms stored corresponding to address data that is the signal data selected by said selector, said each of the data of signal waveforms corresponding to each of said signals differentially encoded.

A modulation method for time division multiple access comprising:

• differentially encoding transmission data in odd-numbered and even-numbered time-slots respectively in a first encoder and a second encoder, each of said first and second encoders are provided corresponding to each of said odd-numbered and even-numbered slots;
• passing a narrow-banded portion of the signals differentially encoded by said first and second encoders in a first filter and a second filter, each of said first and second filters provided corresponding to each of said first and second encoders;
• and,
• combining each signals output from said first and second filters to generate transmission signals.

A modulation method for time division multiple access comprising:

• differentially encoding transmission data in odd-numbered and even-numbered time-slots respectively in a first encoder and a second encoder, each of said first and second encoders are provided corresponding to each of said odd-numbered and even-numbered slots;
• transforming the signals which are differentially encoded by said first and second encoders in a first and second shift registers, to parallel signal data by means of applying a shift operation for said signals which are differentially encoded, each of said first and second filters provided correspondingly to each of said first and second encoders;
• selecting a corresponding one of said parallel signal data in accordance with said odd-numbered time-slot or even-numbered time-slot;
• and,
• reading each of the data of narrow-banded signal waveforms stored in a ROM corresponding to address data that is the selected signal data, said each of the data of signal waveforms corresponding to each of said signals differentially encoded.