| 摘要 |
PURPOSE:To prevent the output waveform of an RF signal from being saturated with the dispersion of the output current of an optical pickup even if a driving voltage is low by changing the operation reference voltage level of an adder by an RF signal peak detecting output outputted from the adder. CONSTITUTION:In the RF signal amplifier circuit, a peak detecting circuit 16 detects the peak level of an RF signal Vout extracted from the adder 13, a comparator 17 compares a peak detecting signal level Vp with a reference voltage Vo and generates a control signal corresponding to the difference voltage to control an output current to be outputted from a variable current source 15. Consequently, the current value I can be changed in accordance with the change of the peak level of the RF signal Vout independently of the adjustment of a variable resistor VR.
|
