| 摘要 |
An arbitrary threshold value (Ei 0 ) is established which defines a boundary as to activating an RF-AGC circuit ( 21 ) if the value of the field intensity (Ei) of a received signal is greater than what value while the value of the field intensity of a signal at a desired frequency being a predetermined value (Ei 0 ) in a weak field area. The established value (Ei 0 ) is used to provide a threshold value establishing/controlling part ( 22 ) that controls the ON/OFF of the operation of the RF-AGC circuit ( 21 ). In this way, a set maker or the like of an IC including an automatic gain control part ( 11 ) can perform a field test or the like such that a preferable value obtained by a result of the field test or the like can be used as an AGC start level (Ei 0 ), whereby an optimum AGC control can be performed based on the preferable AGC start level (Ei 0 ).
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