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This brief presents a design method of analog predistorter (APD) for Doherty power amplifiers (DPAs) based on minimum gain and phase deviation to improve the output adjacent channel leakage power (ACLR). To prove this method, the normalized deviation is formulated based on the non-linear analysis of DPAs’ gain and phase, which is a new joint design indicator between DPAs and APDs. Then an APD design and linearisation performance prediction platform is constructed using this indicator as the core. An APD consisting of two T-networks in series is designed as an example of an existing DPA. It has low circuit complexity and low power consumption, which can effectively improve the AM-AM and AM-PM of the DPA after optimization. Under the excitation of a 40 MHz, 64-QAM modulated signal, the results show that the ACLR of the DPA output is improved by nearly 10 dB with the proposed APD, from -34.4/-34.3 dBc to -43.9/-45.6 dBc. In case of constant output ACLR, the application of the APD also increases the output power and efficiency. Moreover, the proposed APD still has good linearization performance under the excitation of 80 MHz, 64-QAM modulated signal.

In practical scenarios, digital predistortion (DPD) systems are typically deployed on hardware platforms. However, the current time delay alignment algorithm, a critical component of DPD processing, requires substantial hardware resource allocation. Consequently, this brief introduces a novel delay estimation algorithm aimed at simplifying the time alignment segment, including both integer and fractional elements. The integer alignment method is established on an adaptive filter framework, while the fractional component leverages a recursive least square (RLS) algorithm, based on a Farrow structure, to circumvent extensive matrix calculations. The complexity analysis, coupled with experimental results show that the proposed methods not only preserve high accuracy but also substantially diminish computational resource demands by 88.7% and 87.8%, respectively, when compared with two prevailing delay estimation techniques. This enhancement notably augments the performance of hardware-based DPD systems.

Purpose:Thalassemia is one of the most common monogenic diseases in southwestern China, especially among the Dai ethnic group. Here, we explore the feasibility of a next-generation sequencing (NGS) screening method specifically for the Dai people.Methods:Blood samples were obtained from Dai people for premarital screening. Double-blind, parallel hemoglobinopathy screening was conducted using both traditional hematological methods (red cell indexes and hemoglobin electrophoresis, then DNA sequencing) and an NGS approach.Results:Among 951 tested individuals, we found a thalassemia carrier rate of 49.5% (471/951) using the NGS screen, in contrast to 22.0% (209/951) found using traditional methods. Almost 74.8% (217/290) of α-thalassemia carriers and 30.5% (25/82) of composite α- and β-thalassemia carriers were missed by traditional screens. The proportion of such α- and β-thalassemia carriers among the Dai people is 8.6% (82/951). For β-thalassemia carriers, the high ratio (66/99) of CD26 mutations may suggest a correlation between CD26 and the environmental adaption of the Dai people.Conclusions:Methodological comparisons demonstrate the superiority of NGS for both sensitivity and specificity, provide a comprehensive assessment of thalassemia screening strategies, and indicate that NGS is a competitive screening method, especially among populations with a high prevalence of disease.Genet Med advance online publication 26 January 2017