| 摘要 |
PURPOSE:To reduce an error rate by inverting the polarity of a spread code for a symbol period or a period of an integer number of multiple of the symbol period to suppress a DC offset in an D/A converter of a receiver. CONSTITUTION:A spread code generating means 5 is made up of a spread code generator 6, a polarity inverter 7, and a selector 8 connecting to a spread modulator 4, an output line of the spread code generator 6 is branched into two, one output line is connected to one switching terminal of the selector 8 and the other output line is connected to the other switching terminal of the selector 8 via the polarity inverter 7. Thus, the selector 8 is switched for a symbol period by a symbol clock, and the spread code generated by the spread code generator 6 is inverted for each symbol and fed to the spread modulator 4. Thus, even when the data signal of the same polarity is consecutive over several symbol periods, no DC offset is produced in the spread spectrum modulation output. |
