| 摘要 |
PURPOSE:To miniaturize the titled system by rotating the arrangement of signal points by pi/4 and coding the result so as to decrease kinds of numerals provided in a ROM table being input values to a roll-off LPF. CONSTITUTION:A coding circuit 1 encodes serial sending data in the unit of n-bit [(n) is an integer and larger than 1], separates the result into X, Y components and gives them to roll-off LPFs 4, 5 respectively via ROM tables 2, 3. Then the result and a carrier generated by a carrier generating circuit 8 are multiplied by multipliers 6, 7, an adder 9 adds them and a modulation signal is outputted. In this case, the arrangement of signal points is rotated by pi/4 and the data are encoded to decrease kinds of numerals to be provided in advance in the ROM tables 2, 3 more than a conventional method. That is, kinds of numerals to be provided in the ROM tables 2, 3 in advance being input values to the roll-off LPFs are less and the device for the titled system is miniaturized. |
