| 摘要 |
PURPOSE:To avoid connection difficulty for a radio circuit by attaching a function to successively and automatically adjust the level of a carrier sense within a range regulated by a law on a microcomputer corresponding to the reception input voltage of a noise. CONSTITUTION:A noise component is extracted by a band-pass filter 1 for noise squelch, and is converted to a DC level by a rectifier 2 for noise squelch circuit. At this time, an RF microcomputer 6 compares the DC level inputted to a comparator reference value automatic controller 3 with a reference value discriminated as H or L by a comparator 4. The reference value of the comparator 4 is changed in proportion to the DC level inputted to the comparator reference value automatic controller 3. Therefore, since the DC level inputted to the comparator reference value automatic controller 3 is increased when the noise under environment in practical use corresponds to the frequency of a control channel to be used, the RF microcomputer 6 controls the reference value of the comparator 4 so as to be set higher. |
