| 摘要 |
PROBLEM TO BE SOLVED: To generate a constellation pattern in real time without any load on software by outputting a constellation pattern that a FIFO means stores in the constellation pattern sending-out timing corresponding to the modulating and demodulating speed obtained by dividing the frequency of the sampling clock for receive data. SOLUTION: A constellation pattern sending-out timing generator 13 generates the constellation pattern sending-out timing by dividing the frequency of the sampling clock for the receive data and outputs the timing. By this output, X- and Y-pattern FIFOs 14 and 15 outputs data which show in-phase components X and orthogonal components Y of respective symbols in the constellation pattern and are properly stored by writing from a CPU. The digital data are converted by X-and Y-pattern D/A converters 16 and 17 into analog data to output X and Y patterns. Consequently, modem performance can be evaluated in real time with the constellation pattern without any load on the software. |
