Related Experiment Video
Updated: Mar 8, 2026

Transmission of Multiple Signals through an Optical Fiber Using Wavefront Shaping
Published on: March 20, 2017
Improving performance of mobile fronthaul architecture employing high order delta-sigma modulator with PAM-4 format
Abstract:
An improved high-order delta-sigma modulator with multi-level quantizer is proposed to enable carrier aggregation of 4G-LTE signals in mobile fronthaul. Different from conventional delta-sigma modulation-based digital mobile fronthaul, a 2-bit quantizer is employed to reduce the quantization noise, which enabling the transmission via PAM-4 based IM-DD channel. Moreover, we employ the 4th-order high-pass filter (HPF) to replace the 1st-order HPF in the conventional delta-sigma modulator, resulting in a much better noise shaping performance. In the experiment, a PAM-4 based mobile fronthaul transmission of 32 aggregated 4G-LTE signals with a CPRI equivalent data rate of 39.32-Gb/s is demonstrated in a single-λ 10-Gb/s IM-DD channel. Significant improvement of 68% is achieved in the average EVM performance compared to the previous delta-sigma modulation-based digital mobile fronthaul.
Related Concept Videos
Upsampling
Design Example
Frequency-Domain Interpretation of PD Control
The proportional control gain, combined with the...
PD Controller: Design
Designing a continuous-data controller requires selecting and linking components like adders and integrators, which are fundamental in Proportional,...
Reconstruction of Signal using Interpolation
Power Factor Correction

