Patent ID: 8488961
Filing Date: 2013-07-16
Classification: G01M,H04B

Abstract:
1. A dispersion detecting apparatus comprising: a received waveform monitor processor including a waveform monitoring circuit for sampling data from the received waveform of a received signal transmitted through a transmission path, and a histogram extracting circuit for extracting histogram data representing an intensity distribution of said received waveform in a voltage direction based on the sampled data from said waveform monitoring circuit; and an amount-of-dispersion detector including a polarization dispersion estimating circuit for determining an extent of lateral symmetry of a received eye pattern waveform of said received waveform which is produced by analyzing the histogram data extracted by said received waveform monitor processor, and estimating an amount of polarization dispersion in said transmission path based on the determined extent of lateral symmetry, wherein said waveform monitoring circuit comprises: an identifier for sampling data higher than an identification threshold value in a voltage direction set from an external circuit, from said received waveform at a timing based on an identification clock input from an external circuit; means for setting the identification threshold value of said identifier; and means for changing the phase of the identification clock input to said identifier; wherein said identifier repeatedly samples a plurality of data from said received waveform while the identification threshold value of said identifier is being varied in the voltage direction and the phase of the identification clock input to said identifier is being varied.