Overlapping action confirming circuit for high frequency of laser

Abstract

Abstract PURPOSE:To decrease a reading error by having a variable means of the high frequency overlapping output of an oscillating circuit for overlapping a high frequency and a detecting means of the change quantity of a laser driving current at the time of a different highs frequency overlapping output and confirming the oscillating action of the oscillating circuit for the high frequency with the size of the change quantity. CONSTITUTION:While a CPU 9 releases an oscillating stopping command signal OST and a high frequency oscillating circuit 8 is set to an oscillating action condition, as well as the oscillating stopping condition of the high frequency oscillating circuit 8, the data for setting the light emitting power are sent to a decoder 28, a light emitting power value is set to PCHK, while the value is held to the value PCHK' the current value of a laser driving current IF is fetched through an A/D converter 24 into the CPU 9. An arithmetic processing is executed concerning whether or not the data of both current values I1 and I2 and constants A1<1, A2<1 and A1<A2 are in the scope of a relational expression A1<=I2<=A2I2. When the expression is satisfied, it is judged that the high frequency oscillating circuit 8 is normally operated, and when the relational expression is not satisfied, it is lighted up or warned that the abnormality is present at the oscillating action of the high frequency oscillating circuit 8. Thus, the reproduction having a small quantity of the reading error can be executed.

Inventors

• 👤 Toyoaki Takeuchi
• 👤 竹内　豊明

Bibliographic Details