Figure 6-2 location of radio frequency delivery chips in radio frequency circuit frames
What's the effect of the radio frequency chip
The english transceiver of the radio frequency delivery chip is a combination of two english words, transmitter and receiver, so it is known by word that the radio frequency delivery chip is capable of delivering and receiving functions that are at the core of the radio frequency delivery and distribution system and that perform the functions of variability, frequency synthesis, signal amplification, filtering, open concerns, etc。
What are the key parameters of the radio frequency chip
Supported working bands (band): each wireless communication system has its own operating frequency range, which is what you often call a frequency range, such as 2g mobile communications with 4 frequency bands, wi-fi with 2 frequency bands near 2. 4 ghz and 5 ghz. The most important thing about radio-frequency chips is what work bands support。
Tx (transmitter) parameters: essentially, the same parameters as those that concern the transmitter's circuits when they are presented in chapter 4 of this book, such as output power, gain, spectrum template, modulation mass, non-linear product indicators, power consumption, etc。
Rx (receiver) parameters: essentially the same parameters as those that concern the receiver circuits, such as sensitivity, dynamic range, non-linear products, etc., as described in chapter 5 of this book。
Power: several circuits are required, each volt。
Usage: per circuit power supply, total power consumption。
Control logic level: control the logical voltage。
Clock type: how many hz are clocks, non-active crystals or active crystals。
Interface type: and what is the interface for the processor or modem。
How to select radio frequency chips
Usually radio frequency delivery chips and processors, or modem, power management chips, etc., are used as a set of programs (often referred to as "sets" ), while a platform (indicator processor) suite is fixed, and the selection of the platform also identifies radio frequency delivery chips. Sometimes, in order to achieve differentiation, radio-frequency delivery chips are replaced with other models, which, from a technical point of view, require a thorough and careful assessment of all the parameters listed above。
Working bands
The work-band or frequency range is the first element of concern and requires an assessment of whether the frequency band supported by the radio-frequency chip meets the requirements of the project according to the specifications of the project to be designed。
Tx arguments
The output power of the radio frequency chips on each frequency segment, e. G. The maximum output power. The maximum output power of the system is determined by the maximum output power of the radio frequency chip, the magnification gain of the power amplifier (pa) and the loss of other circuits. Therefore, the maximum output power of radio-frequency chips influences the selection of the later pa gains. It also affects the selection of pa's maximum input power, which must be lower than the maximum output power of the radio-frequency delivery chip, otherwise it may lead to pa being saturated because of its excessive input power and possibly burning the pa in serious cases。
Spectrum template. The spectrum performance of the output signal of the radio-frequency delivery chip, except for the normal output spectrum template, has different considerations for different wireless communication standards, such as the aclr for wcdma and lte, the acpr for the cdma system, the gsm system and the switch spectrum. The smaller the spectrum decay, the better。
