| 摘要 |
PURPOSE: An apparatus for controlling an IF(Intermediate Frequency) transmission in a mobile communication base station system is provided to constantly maintain an output level of an IF amplifier, regardless of a level of a signal inputted to the IF amplifier, so as to reduce noises while an IF signal is outputted. CONSTITUTION: A detector(120) detects a size of an amplified signal outputted from an IF amplifier(110) into a size of an analog signal, and converts a level of the signal into a DC level to output the signal with the DC level. An A/D converter(130) converts the analog signal having the DC level into a digital signal. A controller(140) compares the digital signal with preset reference data. If the digital data is over the reference data, the controller(140) outputs a reference data value. If the digital data is lower than the reference data value, the controller(140) outputs the digital data. A D/A converter(150) converts a digital data value into an analog DC signal. A filter(160) removes a ripple included in the analog DC signal, and amplifies the analog DC signal to a constant level, then outputs the analog DC signal. A voltage stabilizer(170) outputs the DC signal as an amplification control signal of the IF amplifier(110), and constantly stabilizes an amplification voltage of the IF amplifier(110).
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