Technologies: Back to basics

This section holds some simplicity, clarity, and a solid foundation concepts about communication system design.

Keysight signal studio provides details information about IEEE802.11 packets. Downloading and running on PC are free without instruments attached. Pic1: IEEE802.11 Packet structure illustration

Pic2: Bluetooth Packet structure and UWB FCC requirements

The FFT algorithm reduces the computational complexity of the DFT from O(N^2) to O(NlogN), making it faster and more practical to use for large data sets. *Pic3: FFT is a special type of DFT *

The 4 types of amplifier are showed below by using OP-Amp model. They are V/V, I/I, I/V, V/I. The most of Analog IC design circuits today are coming from these 4 types of amp.
Pic4: 4 types of amplifier

Two types of LTE_A system are existing, TDD and FDD. Keysight signal studio provides details information about these RF packets differences. Downloading and running on PC are free without instruments attached.
Pic5: Spectrum of LTE-A: TDD vs. FDD

RX desense could happen by many reasons. Understanding the Rx architect is the first step to solve RF path caused Rx desense.
Pic6: Typical Zero-IF receiver RF architect

By understanding the limitations of the EVM measurement tool, designers can optimize the design of the PA/LNA and create better DPD/CFR algorithms. This can lead to achieving a better trade-off between EVM and DC power conservation. Pic7: EVM floor illustration

Choosing the best DPD algorithm can be challenging as there is no one-size-fits-all solution. It is important to consider individual use cases and other factors of the PA, such as power efficiency over the full RF output power range and over process, voltage, and temperature (PVT).
Pic8: Which DpD is better?

EVM Separation: Deterministic EVM degradation can be improved by digital enhancement
Pic9: EVM separation

The RF Front-End (RFFE) module packages non-CMOS silicon components such as PA/LNA, filters, switches, and N-duplexers together to achieve better performance with a smaller footprint on the PCB.
Pic10: RFFE module example

Low power design is a multi-faceted process, and different teams typically focus on specific areas within the design. As architects, it is important to have a top-down view of the design process and understand which team is responsible for each aspect of the low power design.
Pic11: Low power design architect view

Using a low power rail can effectively reduce ICQ and ICC, resulting in power savings. However, voltage rail ripples can be a major limiting factor when reducing rail voltages. In modern PDN designs, Switched-Mode Power Supplies (SMPS) and Power Management Integrated Circuits (PMIC) are the two typical types of DC-DC converters used. Excessive voltage ripples are mainly due to SMPS’s transistor inability to handle Di/Dt in cases of large dynamic current consumption, rather than Dv/Dt.
Pic12: Control the voltage ripples of SMPS

The test data obtained during silicon manufacturing follows a Gaussian Mixture distribution. However, in everyday engineering activities, people often assume these datasets follow a Gaussian distribution and make calculations accordingly. Understanding the difference between these two distribution types can be beneficial for system architects.
Pic13: Gaussian Mixture distribution is the production test dataset statistic model

I use ChatGPT at home.
Pic14: ChatGPT vs. Bard