| 摘要 |
PROBLEM TO BE SOLVED: To output an RSSI signal high in precision with a simple configuration without providing an expensive and complicated additional circuit corresponding to an automatic gain control(AGC) means of the digital control system. SOLUTION: A signal from an A/D converter 14 is given to an integration section 15, a voltage or a power component resulting from taking an absolute value of or squaring the amplitude component is integrated for a prescribed time. The integrated value is compared with a prescribed reference value at an RSSI output section 16, and in the case that the integrated value is a prescribed reference value or over, the RSSI output section 16 outputs an RSSI signal. A demodulation section 13 upon the receipt of the RSSI signal establishes code synchronization with an output signal from the A/D converter 14 and demodulates the signal to recover data. On the other hand, in the case of transmission, after confirming the RSSI signal not outputted from the RSSI output section 16 before the start of transmission, processing such as spread spectrum modulation, frequency conversion and filtering processing is applied to data and the processed data are transmitted. |
