Patent ID: 6292119
Filing Date: 2001-09-18
Classification: G02F

Abstract:
An optical analog-to-digital converter for converting an optical analog signal to a digital signal, said converter comprising:a plurality of channels receiving the optical analog signal and providing a bit of the digital signal, said plurality of channels including a first channel providing a most significant bit, a last channel providing a least significant bit, and a plurality of intermediate channels between the first channel and the last channel providing bits of lessening significance from the first channel to the last channel in succession, wherein all of the successive channels after the first channel include;at least one subtraction device receiving the optical input signal and a control signal from a preceding channel, said at least one subtraction device generating an optical subtraction signal that is determined by subtracting a predetermined subtraction value from the optical input signal if a bit generated by a certain one of the preceding channels is high or is determined by passing the optical input signal if the bit generated by the certain one of the preceding channels is low; anda thresholding device being responsive to the optical subtraction signal from the at least one subtraction device and comparing the subtraction signal to a predetermined threshold value, said thresholding device generating a high output signal if the subtraction signal is greater than the threshold value and generating a low output signal if the subtraction signal is less than the threshold value, wherein the output signal from the thresholding device is the output bit for that channel.