Abstract: A detector obtains an output signal from an input signal containing a target signal and outputs the output signal. The detector includes an amplifier configured to receive the input signal and the output signal, compare the input signal to the output signal to output a comparison result; an envelope generator configured to weight a first value and a second value having a sign opposite to that of the first value in accordance with the comparison result, integrate the weighted first value and the weighted second value, and output an integration result as the output signal; and a controller configured to control the envelope generator in accordance with the input signal. The controller controls the envelope generator to mitigate an increase in an absolute value of the integration result when the input signal contains a frequency component other than a frequency component of the target signal.

Abstract: The present disclosure improves tracking characteristics of an envelope detected from an input signal to the input signal. A detector, which obtains an output signal from an input signal containing a target signal, and outputs the output signal, includes: a comparator configured to compare the input signal to the output signal, and output an obtained comparison result; and an envelope generator configured to weight a first value and a second value having a sign opposite to that of the first value in accordance with the comparison result, integrate the weighted first value and the weighted second value, and output an integral value as the output signal. The envelope generator includes a first gain generator configured to output the first value in accordance with an amplitude of the input signal.

Abstract: There is provided an optical disc control device which can perform stable repetitive control without deteriorating the followability of a target value when performing jumping, retry, and long seek.

Abstract: The present invention solves the problems that, in a detection circuit which is mostly configured by analog circuits, the chip size cannot be reduced even using a highly-precise processing, there are many external capacitors and terminals thereof, a plurality of high-speed and large-scale AD converters are required for digitization, the detection precision of a small amplitude signal superimposed on an RF signal is deteriorated, and high-speed sample/hold is required. A significant deletion of analog circuits can be realized by generating a digital detection signal directly from an analog RF signal using a simple analog circuit configuration of a detection control means including a comparator, a threshold DAC for setting a threshold value, and an integrator.