This paper proposed a modulation recognition algorithm for M-QAM signals by the constellation diagram which does not require the prior information. Firstly, this scheme estimates the modulation parameters. Secondly, it reconstructs the received signals' constellation and uses kmeans cluster algorithm to compute the number of the signal constellation points which are as a recognition feature used for classification. The experimental simulation results proves that this method is effective for M-QAM signals, and the correct recognition ratio reaches 100% under the condition that the SNR is higher than 15dB. So it has relatively preferable practical value.
Due to the friction between rolls and sheet surface, shear texture inevitably occurs in the surface layer of the hot‐rolled sheets in electrical steel. The shear texture contains Goss texture {110}<001>, brass texture {110}<112>, and copper texture {112}<111>. The existence of shear texture and its corresponding microstructure affect the texture distribution in the subsequent normalized sheets, cold‐rolled sheets, and final sheets. Electron backscattered diffraction and reaction stress model are used herein to study the formation conditions of {112}<111> orientation in the hot‐rolled sheets. The results show that initial rotated cube orientation tends to rotate around transverse direction to the copper orientation during hot rolling due to the shear action. Different shear orientations can be formed in different regions of an initial coarse columnar grain during hot rolling, because of the change in surrounding environment reaction and the difference of the shear strain at different thickness positions. The thinner the hot‐rolled sheet is, the smaller the dynamic recrystallization region with shear orientation, and there is almost no copper texture in the thinnest hot‐rolled sheet. The simulation results show that the copper texture is easy to form under the action of σ23 and σ22 reaction stresses.
The columnar grains are composed of near‐{100} subgrain variants, Σ3 variants, and untransformed coarse columnar grains. As the Si content increases from 0.35% to 1%, the untransformed columnar grains are remarkably reduced, but the {100} subgrain variants still exist significantly. The phase transformation strain induced by {100} subgrain variants is large, while that induced by small equiaxed grains, which conform to Σ3 relationship with columnar grains, is lower. During the twice‐phase transformations, even if the variants appear randomly, the probability of occurrence of the {100} variants is 33.3%. Moreover, the {100} subgrain variants mainly appear as single variants because the phase transformation strain of the single variant, which is independent of orientation, is higher than that of the variant pair. Although the strain energy of the {100} subgrains has no advantage, the low‐angle grain boundary interface energy is lower than other high‐angle grain boundaries except for Σ3, which contributes to the appearance of the {100} subgrain variants. The appearance of the Σ3 relationships is to reduce the overall energy, rather than the simple strain accommodation behavior between variants. Beyond that, the actual phase transformation does not follow the strict K−S relationship.
Equivalent phase comparison frequency (EPCF) is an important parameter between two frequency signals, and it shows their phase correlation. It is much higher than anyone of the two frequencies, and its period is equal to the group phase shift corresponding two most adjacent phase coincidences between the signals. For example, to two frequency signals with several MHz frequency, their EPCF can be several GHz or higher. This concept is based on time or phase analysis and processing approaches, not those of frequency. With it to process time and frequency signals much higher phase processing resolution can be obtained. It is special effective for
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