| 摘要 |
PURPOSE:To shorten the time required for identification by considerably decreasing the number of bits in an identification number required for identification, to save the energy of a transmitter and to effectively utilize radio wave resources. CONSTITUTION:This equipment is provided with a transmitter and receiver 2. The transmitter transmits a PN code set composed of PN codes for a prescribed length. The receiver 2 outputs radio waves, which are received through an antenna 21, through an RF/IF 22 to a correlator 23. The envelope of a correlation spike (d) from the correlator 23 is detected by a DET 24, a detecting output (g) is obtained and binarized by a VCOMP 26, and a correlation pulse (h) is obtained. A reference signal generating circuit 25 generates a signal for which a PN code output (j) from a PNG 25-1 and a high frequency signal output (k) of an RFG 25-2 are multiplied by a DBM 25-3. Corresponding to a control signal from an identifying means 27, the PNG 25-1 switches the kind of the PN code. Only when it is judged by the identifying means 27 that all the received PN codes can be correlated, the reception of transmitted data is started and in the other case, a reception waiting state is continued. |
