Skills required for RF circuit board engineers

Entering the 5G era, radio frequency circuit board has become the focus of hot discussion in the industry.

Traditionally, a mobile phone that can support phone calls, text messages, network services and APP applications generally consists of five parts: RF part, baseband part, power management, peripherals and software.

Radio frequency part: usually the part that sends and receives information;

Baseband part: Usually the part of information processing;

Power management: Generally it is the part of saving electricity, because mobile phone is energy limited equipment, so power management is very important;

Peripherals: generally including LCD, keyboard, case, etc.;

Software: Generally includes system, driver, middleware, application.

In the mobile phone terminal, the most important core is the RF circuit board and baseband circuit board. Rf circuit board responsible for RF transceiver, frequency synthesis, power amplification; Baseband circuit boards are responsible for signal processing and protocol processing. So what is the relationship between RF circuit boards and baseband circuit boards?

The earliest application of Radio frequency is radio -- radio broadcasting (FM/AM), which is still the most classic application of radio frequency technology and even radio field.

Baseband is the signal with the center point of the band at 0Hz, so baseband is the most basic signal. Some people also call baseband "unmodulated signal", which used to be true, such as AM is modulated signal (no modulation, after receiving can be read by the voice component).

But for the modern communication field, baseband signal usually refers to the signal with the center point of the spectrum at 0Hz after digital modulation. And there is no clear idea that baseband must be analog or digital, it all depends on the implementation mechanism.

Anyway, baseband circuit boards can be thought of as including modems, but not just modems, but also channel codec, source codec, and some signaling processing. Rf circuit boards, on the other hand, can be regarded as the simplest baseband modulated signal up-conversion and down-conversion.

The so-called modulation, is the need to transmit the signal, through certain rules to the carrier above and then through the wireless Transceiver (RF Transceiver) sent out the project, demodulation is the opposite process.

This section describes the specific tasks of radio frequency engineers

1. Circuit system analysis

In some projects of communication equipment companies, RF engineers are responsible for system analysis of the circuit of the entire RF system, guidance of system design indicators, allocation unit module indicators, specification of EMC design principles, and put forward the function and performance requirements of accessories. .

2. Circuit principle design

Including block diagram design and circuit design, which are essential skills for RF engineers. This is also an extension of system design. How to achieve the goal of system design is the purpose of circuit principle design, and it is also the "antecedent" of device selection evaluation, because the process of circuit design is also a process of device selection.

3. Device selection and evaluation

To achieve the index requirements of the circuit, it is essential to choose the right device, this process is actually carried out at the same time with the circuit principle design. How to choose the corresponding device, and which of the same type of device is more suitable for our product design? Cost, performance, process requirements, packaging, supplier quality, delivery time, etc., are more important factors to consider.

4. Software simulation

Whether it's ADS, MWO, CST, HFSS, you're going to use one or two emulators. Simulation software can't make your design 100% accurate, but it will never make your design deviate from the basic direction, at least they are accurate in qualitative simulation.

So be sure to learn to use one or two or more types of simulation software. Its basic function is to allow you to qualitatively analyze your design. There will always be errors, but it can increase your confidence.

5.PCB Layout

Principle is like the theoretical basis, ten thousand applications can only based on a theory, several products may only have a schematic, but its wiring is not the same. Take mobile phone as an example. Many companies design the same mobile phone scheme with the same schematic diagram, but different companies produce different PCB boards, one is different in appearance, the other is different in performance.

Performance difference, in fact, is the difference of PCB Layout. Meet the requirements of the PCB, its layout and wiring take into account performance, appearance, technology, EMC and other aspects. Therefore, PCB Layout is also a very important skill.

6. Debug and analyze

This debugging is not the same as production debugging. Production debugging is mandatory. The focus of debugging of research and development products is to find and solve problems. Debugging is a process of summarizing and accumulating experience. It is not to accumulate debugging experience through debugging, but to accumulate design experience through debugging. Many problems may not be found in the design, so after debugging, we know how to avoid these problems in the future design, how to improve these problems.

Debugging is also the most effective way to practice theory, we can understand the theoretical knowledge qualitatively through debugging process.

7. Test

Testing is for debugging, and debugging is for design (and design is for marketing). Rf engineers must be proficient in using various RF testing instruments, whether spectrum analyzer, network analyzer, signal source, oscilloscope, power meter, noise factor tester, comprehensive tester, etc.

8. Groundwork

Can do more basic work, can own welding on their own welding, it is impossible to debug when someone stay on the side to help change the capacitance and inductance.