Knowledge Sharing

Hollis Electronics publishes white papers on topics relevant to telecommunications test equipment and environments. With more than 45 years of industry experience the HEC team has tackled and solved tough challenges for their customers.  

Why Modems with Adaptive Equalizers Aren't Enough

Proper equalization of a signal is very important to the quality of the signal and to the impact on revenue both directly and indirectly.  Delivering a truly equalized signal gives the receiver the best quality data, which leads to greater system performance and customer satisfaction.  In addition, proper equalization gives the opportunity to communications providers to boost their revenue by increasing the amount of data that can be transmitted at one time through the channel.  Read more...

Fade Weights & Update Rates
Incorrect Assumptions Result in Distortions that Don't Exist

Frequently people assume if the maximum fade rate of a weight is F, then sampling this waveform at 2F or more is sufficient to meet the Nyquist Criteria. Weights generated at sample rates lower than the full sample rate must be filtered properly, if they are not, the images of the weight signal will also be applied to the INPUT signal (which is typically sampled at a substantially higher rate then the weight signal). This is not proper simulation. These weights will cause distortions that do not exist in the real world, which the simulator is trying to simulate.  Read more...