| 摘要 |
PURPOSE:To measure the quantity of interference independently of a modulation system by measuring a reception level from reception level or reception information at a reception side and using the mean value of a time of presence of a signal and the mean value of time of absence of a signal and estimating the mean reception level of a desired wave and the mean reception level of an interference wave. CONSTITUTION:An A/D converter circuit 2 converts a reception level into a digital signal and outputs it to a signal presence deciding circuit 3 and an interference quantity calculation circuit 4. When a preamble signal is detected or a reception level is higher than a preset 1st threshold level, the signal presence deciding circuit 3 decides it as the presence of a signal and when a post-amble signal is detected or a reception level is lower than a preset 2nd threshold level, the signal presence deciding circuit 3 decides it as the absence of a signal and outputs a deciding signal to the interference quantity calculation circuit 4. The interference quantity calculation circuit 4 obtains a mean reception level Lon for the period of presence of signal, a means reception level Loff of the period of the absence of signal and a transmission time ratio P from the deciding signal of the presence/absence of signal and the reception level signal, calculates an interference quantity DUR and outputs the result. |
