Light signal detecting circuit
AssigneeSamsung Electronics Co., Ltd.
InventorChul-woo Lee
Life of this patent
Estimating the term…
Abstract
A light signal detecting circuit which receives via a light detector light radiated from a laser diode oscillated as a multimode by a high frequency driving signal and reflected from an optical disk, amplifies a current signal proportional to the amount of the received light to a light detecting signal and outputs the signal, further includes a phase sensitive detector for selectively outputting from the current signal only a signal component having the same frequency and phase as the high frequency driving signal for driving said laser diode. Accordingly, a signal component with different frequency and phase from the output of laser diode is intercepted, and only a signal component with the same frequency and phase as the output of laser diode is detected.
Claims6
A light signal detecting circuit for use in an optical disk player having a laser diode oscillated in a multi-mode by a high-frequency driving signal, the laser diode radiating light which is reflected from the surface of an optical disk, said detecting circuit comprising:
- a pair of light detector means, each for respectively converting light reflected from the optical disk into a detecting signal proportional to the amount of light received;
- a pair of phase-sensitive detector means each for filtering a respective one of said detecting signals of said light detector means according to the high-frequency driving signal and each outputting a filtered signal having the same frequency and phase as the high-frequency driving signal;
- and
- a differential amplifier means for outputting a differential signal representing the difference between said filtered signals of said phase-sensitive detector means.
A light signal detecting circuit for use in an optical disk player having a laser diode oscillated in a multi-mode frequency by a high-frequency driving signal, the laser diode radiating light which is reflected from the surface of an optical disk, said detecting circuit comprising:
- a pair of light detector means, each for respectively converting light reflected from the optical disk into a detecting signal proportional to the amount of light received;
- a differential amplifier means, coupled to receive said detecting signals of said pair of light detector means, for outputting a differential signal representing the difference between said detecting signals;
- and
- a phase-sensitive detector means for filtering said differential signal according to said high-frequency driving signal and outputting a filtered signal having the same frequency and phase as said high-frequency driving signal.
Dependencies are inferred from the claim text.