Method and device for adjusting digital pre-distortion
A technology of digital pre-distortion and data sampling, which is applied to parts of amplification devices, synchronization/start-stop systems, amplifiers, etc., and can solve problems such as not reaching optimal performance
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[0075] f(x[n], x[n-d], y[n], y[n-d]) = 1 => this would correspond to a histogram.
[0076] f(x[n], x[n-d], y[n], y[n-d])=conj(x[n])*x[n]=>every cell energy.
[0077] f(x[n],x[n-d],y[n],y[n-d])=conj(x[n]-y[n])*(x[n]-y[n])=>every Group error energy.
[0078] If the collection of samples consists of multiple time intervals, then H will be calculated independently for each interval t t matrix and then the amplitude matrix for all bins will be obtained as: H=Σ t h t
[0079] A simple variation is to use y[n] and y[n-d] instead of x[n] and x[n-d] for (1) and (2), ie, replace the transmitted samples with the received samples to determine the Which cell of the matrix the sample belongs to.
[0080] The preceding paragraphs show an example procedure to obtain the amplitude change matrix for both the reference capture and the capture under inspection assuming the number of quantization intervals M, the set of thresholds A, and the real function f of the two complex samples. This ...
example 500
[0093] As shown in the figure, example 500 includes graph 502 ( Figure 5A ) and graph 504 ( Figure 5B ). Graph 502 includes an x-axis 506 , a y-axis 508 and a set of contour lines 510 . The graph 504 includes an x-axis 512 , a y-axis 514 and a set of contour lines 516 .
[0094] The x-axis 506 and x-axis 512 represent the equivalent for Figure 5A and 5B The described amplitude changes the absolute value of the early samples of the quantization interval i of the matrix H(i,j). y-axis 508 ( Figure 5A ) and y-axis 514 ( Figure 5B ) means equivalent to Figure 5A and 5B The absolute values of late samples for quantization interval j of the described amplitude change matrix H(i,j). Contour set 510 ( Figure 5A ) is how the amplitude matrix of a good capture buffer has a maximum in the diagonal of the graph (where the maximum is around x=0.3, y=0.3) and shows a sharp decrease outside of the diagonal values. Contour set 516 ( Figure 5B ) shows values below 10 (5...
example 600
[0099] Example 600 uses a different amplitude change matrix than that used in example 500 . Graph 602 ( Figure 6A ) and graph 604 ( Figure 6B ) represents the same amplitude change matrix associated with the two identical wideband code division multiple access (WCDMA) signals (each having a 5 MHz BW and split to occupy a total BW of 20 MHz) with a 20 dB power difference used in example 500.
[0100] Examples of properties of good amplitude modification matrices known to give good DPD performance results and amplitude modification matrices known to give poor performance results have been shown. These results can be further illustrated using graphs. It should be noted that to generate Figure 5A and 5B The WCDMA signals of the examples of 6A and 6B are used for explanation purposes only. Aspects of the invention are applicable to any system that has real-time changes in the frequency distribution of the signal. For example, OFDM signals like those used in Long Term Evolu...
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