CO-OFDM (COherent light-Orthogonal Frequency Division Multiplexing) system channel estimation method based on channel impulse response filtering

The invention provides a CO-OFDM (COherent light-Orthogonal Frequency Division Multiplexing) system channel estimation method based on channel impulse response filtering, which can improve the noise resistance capability for channel estimation with smaller system expenditure. The method comprises the following steps of: carrying out IFFT (Inverse Fast Fourier Transform) transform on a channel transfer function estimated by an LS (Least Square) channel to obtain a channel impulse response; calculating the length of the channel impulse response according to optical fiber channel parameters, such as dispersion, polarization mode dispersion and the like; constructing a Blackman window function according to the length of the channel impulse response; carrying out time domain multiplication on the channel impulse response and the Blackman window function; carrying out FFT transform on the processed channel impulse response to obtain a channel transfer function of which the noise is filtered out ...

一种用于高速制造双向拉伸聚丙烯薄膜专用树脂

A special resin used for quickly preparing the bidirectional stretching polypropylene film contains homopolymerized polypropylene resin, halogen absorbent and the antioxidizing agent which is the composition of tetra [beta-(3,5-dibert-butyl-4-hydroxyphenyl) propionate] pentacrythritol ester, tri (2,4-di-tert-butyl phenyl) phosphite, and 1,3,5-tri (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate. Its advantage is high resistance to thermal oxidization and degradation.

Chines medicine for treating vitiligo and preparation method thereof

The present invention discloses a Chinese medicine for curing vitiligo and its preparation method. Its prescription comprises ledebouriella root, Chineses angelica root, ligusticum root, flowery knotweed root, biota seed, carthamus flower, astragalus root, ovate atractylodes root, salvia root, psoralea seed ,dahurian angelica root, tribulus fruit, dodder seed, prepared rehmannia root ,sping jujube kernel, corydalis tuber, akebia fruit and codonopsis root. Its preparation method includes the following steps: using prepared flowery knotweed root; stir-frying Chinese angelica root and ligusticumroot with wine; stir-frying prepared rehmannia root, psoralea seed, dodder seed, codonopsis and ovate atractylodes root; cooking tribulus fruit; stir-frying salvia root with pig blood; mix-frying astragalus root with honey; light stir-frying spiny jujube kernel and frosting biota seed. Said Chinese medicine has no abnormal side effect ,and its total effective rate is up to 95%, curative rate is...

Chinese medicine for treating vitiligo and preparation method thereof