Patent ID: 11956018
Assignee: FUJITSU LIMITED
Field: Telecommunications (Electrical engineering)
Classification: CPC H | IPC H

Claim 7:
8. An optical transmitter comprising:
a signal processor that outputs a sample value;
a quantizer;
a digital-to-analog converter that performs analog conversion on a quantization value; and
an optical modulator that is driven based on an output of the digital-to-analog converter,
the quantizer includes:
a clipper circuit configured to remove a value exceeding a quantization range of the sample value which is sampled from a transmission data at a predetermined rate which is higher than a frequency of the transmission data and obtain clipped sample values; and
a noise shaper circuit coupled to an output of the clipper circuit and configured to determine a plurality of candidates for a quantization level based on each of the clipped sample values, obtain a value by adding a minimum noise in which a noise in a specific frequency region is minimum among noises generated in each candidate to the sample value and output an obtained value as a quantization value.