Apple

To improve efficiency, PA must be designed beyond the classic class-AB, together with enhancement using envelope tracing, or envelope elimination and restoration (EER, or polar transmitter).. Those designs come with impairments or nonlinear distortion that need to be clean up using digital signal processing techniques.. You will interact with RF/analog designers, software or firmware engineers, digital designers, product engineers and architects to define and specify parts in the wireless systems.. Hands on experience on lab testing and characterization (such as spectrum analyzer, signal generator, signal analyzer, power meter, etc. Preferred to understand communication theory & signal processing related algorithms design (such as timing recovery, signal estimation and detection, automatic gain control, channel estimation, equalization, coding theory, etc.)

system engineer

<h3>Senior Wireless System Engineer – DSP for Power Amplifier Linearization</h3> At Apple, we work every single day to craft products that enrich people’s lives. Do you love working on challenges that no one has solved yet? Do you like changing the game? We have an opportunity for a forward-thinking and unusually hardworking Wireless System Engineer. As a member of our dynamic group, you will have the rare and extraordinary opportunity to craft upcoming products that will delight and encourage millions of Apple’s customers every single day.For wireless system, power amplifiers (PA) in the transmitter are the main source of power consumption. To improve efficiency, PA must be designed beyond the classic class-AB, together with enhancement using envelope tracing, or envelope elimination and restoration (EER, or polar transmitter). Those designs come with impairments or nonlinear distortion that need to be clean up using digital signal processing techniques. RF/analog architectures, with the help of DSP, their optimizations and calibrations are the critical technique to achieve such high performing systems.In this technical role, you will be at the center of a silicon design group responsible for using digital algorithm or method to improve the PA efficiency, reducing power consumption, but with acceptable linearity for high data rate applications. You will mainly work on architecting various calibration and correction methods for implementation in hardware/firmware and validation of overall performance enhancement through lab measurement. You will interact with RF/analog designers, software or firmware engineers, digital designers, product engineers and architects to define and specify parts in the wireless systems. Key Qualifications <ul><li> Extensive experience in designing relevant signal processing for wireless communications systems. </li><li> Proven track record of optimization algorithm and its applications to RF calibration </li><li> Good understanding of the methods to estimate various RF impairments via direct equipment measurement or self-testing via loopback. </li><li> Experiences in digital predistortion, crest-factor reduction, nonlinear crosstalk/interference cancellation, and real-chip bring-up in lab </li><li> MATLAB or Python or C/C++ for algorithm development, modeling and simulation. </li><li> Hands on experience on lab testing and characterization (such as spectrum analyzer, signal generator, signal analyzer, power meter, etc.). </li><li> Some understanding of RF and analog components/modules composited of wireless communication systems, the possible impairments from those components, their impact to MIMO OFDM signals, and the corresponding calibration and impairment reduction methods/algorithms. </li><li> Preferred to understand communication theory & signal processing related algorithms design (such as timing recovery, signal estimation and detection, automatic gain control, channel estimation, equalization, coding theory, etc.) </li><li> Preferred to have some knowledge in existing wireless communication protocols: 5G-NR/LTE/WCDMA/GSM, 802.11 WiFi, and/or Bluetooth/BLE </li><li> Course works and experience in circuit design – a plus </li></ul> Description In this role, core responsibilities include, but are not limited to, the following:•Design and simulate state-of-the-art wireless transmitter for very high data rate applications.•Investigate innovative PA architectures, calibration algorithms, processing structures for performance enhancement.•Architect HW/FW/SW partitioning of various calibrations for area and time efficiency.•Implement system models of the analog front-end design, impairments and come up with right controls and calibrations in C and MATLAB for optimal system performances.•Work with digital designers to realize these methods with power and area efficient digital implementations.•Work with firmware designers to realize these methods with high efficiency software implementation, and possibility hardware acceleration.•Bring up, test and characterize real silicon with relevant implementation in lab. Education & Experience BS and 10+ years of relevant experience required. MSEE/PhD preferred <ul><li> At Apple, base pay is one part of our total compensation package and is determined within a range. This provides the opportunity to progress as you grow and develop within a role. The base pay range for this role is between $161,700.00 and $284,900.00, and your base pay will depend on your skills, qualifications, experience, and location. Apple employees also have the opportunity to become an Apple shareholder through participation in Apple’s discretionary employee stock programs. Apple employees are eligible for discretionary restricted stock unit awards, and can purchase Apple stock at a discount if voluntarily participating in Apple’s Employee Stock Purchase Plan. You’ll also receive benefits including: Comprehensive medical and dental coverage, retirement benefits, a range of discounted products and free services, and for formal education related to advancing your career at Apple, reimbursement for certain educational expenses — including tuition. Additionally, this role might be eligible for discretionary bonuses or commission payments as well as relocation. Learn more about Apple Benefits. Note: Apple benefit, compensation and employee stock programs are subject to eligibility requirements and other terms of the applicable plan or program. Apple is an equal opportunity employer that is committed to inclusion and diversity. We take affirmative action to ensure equal opportunity for all applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, disability, Veteran status, or other legally protected characteristics. </li>
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