Photo detecting circuit and noise elimination method
AssigneeNEC Corporation
InventorsSeigo Takahashi, Akio Tajima, Takeshi Takeuchi, Akihiro Tanaka, Wakako Maeda
Life of this patent
Estimating the term…
Abstract
In a photo detecting circuit using an avalanche photodiode (APD), a pulse noise mask signal indicating the timing of occurrence of a pulse noise is generated by XORing a reverse-bias-pulse application timing signal and its delayed signal. Pulse noises are eliminated by ANDing an output signal of the APD and the pulse noise mask signal. Alternatively, a pulse noise is estimated by taking the average for the output current signal a given number of times. Pulse noises are eliminated by subtracting the estimated pulse noise from the APD output signal.
Claims20
A photo detecting circuit using a photo detecting device, comprising:
- a timing generator for generating a timing signal;
- a power supply for applying a pulse voltage to the photo detecting device according to the timing signal;
- a mask generator for generating a pulse noise mask signal indicating timing of occurrence of pulse noises based on the timing signal;
- and
- a pulse noise eliminator for eliminating the pulse noises from an output signal of the photo detecting device by using the pulse noise mask signal, to produce a photo reception signal.
A photo detecting circuit using a photo detecting device, comprising:
- a timing generator for generating a timing signal;
- a power supply for applying a bias pulse voltage to the photo detecting device according to the timing signal;
- an estimator for estimating a noise component by averaging a predetermined number of output signals of the photo detecting device;
- and
- a subtraction section for subtracting the estimated noise component from an output signal of the photo detecting device to produce a photo reception signal.
A method for eliminating noises from an output signal of a photo detecting device, comprising:
- generating a timing signal;
- applying a bias pulse voltage to the photo detecting device according to the timing signal;
- generating a pulse noise mask signal indicating timing of occurrence of pulse noises based on the timing signal;
- and
- eliminating the pulse noises from an output signal of the photo detecting device by using the pulse noise mask signal.
A method for eliminating noises from an output signal of a photo detecting device, comprising:
- generating a timing signal;
- applying a bias pulse voltage to the photo detecting device according to the timing signal;
- estimating a noise component by averaging a predetermined number of output signals of the photo detecting device;
- and
- subtracting the estimated noise component from an output signal of the photo detecting device to produce a photo reception signal.
A program instructing a computer to eliminate noises from an output signal of a photo detecting device, comprising:
- generating a timing signal;
- applying a bias pulse voltage to the photo detecting device according to the timing signal;
- generating a pulse noise mask signal indicating timing of occurrence of pulse noises based on the timing signal;
- and
- eliminating the pulse noises from an output signal of the photo detecting device by using the pulse noise mask signal.
A program instructing a computer to eliminate noises from an output signal of a photo detecting device, comprising:
- generating a timing signal;
- applying a bias pulse voltage to the photo detecting device according to the timing signal;
- estimating a noise component by averaging a predetermined number of output signals of the photo detecting device;
- and
- subtracting the estimated noise component from a latest output signal of the photo detecting device to produce a photo reception signal.
Dependencies are inferred from the claim text.