| 摘要 |
PURPOSE: To improve data transmission efficiency by providing a comparator means comparing a reference with an output of any correlation device among plural correlation devices conducting correlation demodulation to information channels so as to eliminate the need for a delimiter for a start frame in a data stream. CONSTITUTION: An A/D converter 201 converts a base band multiplex signal into digital data and a digital correlation device 202 applies correlation demodulation to each information channel. Then a comparator means 205 is connected to an output of a correlation device 202 and compares its correlation output with a reference value. Whether or not modulation data are in existence in a concerned information channel, that is, whether or not an information signal is received is discriminated by providing the comparator means 205 comparing the correlation output with a threshold level in this way. The comparator means 205 does not discriminate reception data symbol but, discriminates reception signal power. |
