Abstract: In a DAC device, a distortion correction function g1(x) of a harmonic obtained from a result of a frequency analysis on an analog output signal of a DAC circuit is obtained. A correction value is determined based on the correction function g1(x) in accordance with an input digital signal, and is previously stored in a memory. A nonlinear correction circuit reads a corresponding correction value from the memory in accordance with the value of a digital signal output from a digital filter, and transmits the correction value to a subtractor. The subtractor subtracts the correction value from the digital signal output from the digital filter.

Abstract: In a DAC device, a distortion correction function g1(x) of a harmonic obtained from a result of a frequency analysis on an analog output signal of a DAC circuit is obtained. A correction value is determined based on the correction function g1(x) in accordance with an input digital signal, and is previously stored in a memory. A nonlinear correction circuit reads a corresponding correction value from the memory in accordance with the value of a digital signal output from a digital filter, and transmits the correction value to a subtractor. The subtractor subtracts the correction value from the digital signal output from the digital filter.

Abstract: A white dot out detecting device according to the present invention comprises a recording/reproduction control signal generator for generating a recording/reproduction control signal showing a recording state or a reproducing state of an optical disk, a variable gain amplifier for amplifying and outputting an information signal read from the optical disk and adjusting a gain in the amplification based on the recording/reproduction control signal, an envelope detector for detecting an output envelope of the variable gain amplifier, an integrator for integrating an output of the envelope detector, a slice level setting unit for setting a slice level as a reference for detecting a white dot out based on an output of the integrator, a comparator for detecting the white dot out based on comparison of the output of the envelope detector and the slice level to each other, and a level shifter for temporarily shifting the slice level to a high-level side when a change of the recording/reproduction control signal is de

Abstract: During a predetermined period of time after the operation of an optical disc drive has changed from recording to playback or from playback to recording, a first monomulti circuit outputs a pulse signal according to the operation change of the optical disc drive. On receipt of the pulse signal, a capacitor included in an integration circuit is short-circuited at a predetermined reference voltage to fix the output value of the integration circuit at the reference voltage. After the period has passed, on receipt of a pulse signal outputted from a second monomulti circuit, a resistor included in the integration circuit is short-circuited, and an envelope signal is integrated with a time constant being reduced, whereby detection of a false defect signal is avoided, and defect detection can be speedily restarted.

Abstract: A white dot out detecting device according to the present invention comprises a recording/reproduction control signal generator for generating a recording/reproduction control signal showing a recording state or a reproducing state of an optical disk, a variable gain amplifier for amplifying and outputting an information signal read from the optical disk and adjusting a gain in the amplification based on the recording/reproduction control signal, an envelope detector for detecting an output envelope of the variable gain amplifier, an integrator for integrating an output of the envelope detector, a slice level setting unit for setting a slice level as a reference for detecting a white dot out based on an output of the integrator, a comparator for detecting the white dot out based on comparison of the output of the envelope detector and the slice level to each other, and a level shifter for temporarily shifting the slice level to a high-level side when a change of the recording/reproduction control signal is de

Abstract: During a predetermined period of time after the operation of an optical disc drive has changed from recording to playback or from playback to recording, a first monomulti circuit outputs a pulse signal according to the operation change of the optical disc drive. On receipt of the pulse signal, a capacitor included in an integration circuit is short-circuited at a predetermined reference voltage to fix the output value of the integration circuit at the reference voltage. After the period has passed, on receipt of a pulse signal outputted from a second monomulti circuit, a resistor included in the integration circuit is short-circuited, and an envelope signal is integrated with a time constant being reduced, whereby detection of a false defect signal is avoided, and defect detection can be speedily restarted.

Abstract: The disclosure relates to a digital to analog converter capable of suppressing "glitches" or transient spikes in the analog output signal. The digital to analog converter includes a plurality of current switches corresponding to the number of digital input bit signals and a resistive ladder of the conventional R-2R configuration. The R-2R ladder network has a plurality of input ports each connected to the output of a corresponding current switch. Logic inputs to the current switches determine which of the current switches are to be turned on to supply reference currents to corresponding input ports of the ladder network which in turn decrements the received reference currents by a factor of 2 as they pass through each stage to provide an analog output signal at the output terminal of the converter.