Research On Handset Base-band System Founding On DSP Processor

The modern society is an information society, and information transmission needs to carry on massive communication. As the requirement of the person's communication increasing, providing information transmission at anytime, anywhere, to anyone is the target of communication in the future. The mobile communication place an important role on the way to get the target.The modern society is an information society, and information transmission needs to carry on massive communication. As the requirement of the person's communication increasing, providing information transmission at anytime, anywhere, to anyone is the target of communication in the future. The mobile communication place an important role on the way to get the target.Person access system (PAS) is one kind of numerous fashion of mobile communication. PAS handset have many good points, such as low transmit power, dial easy, low expenses, clear sound quality, long speak time, small structure etc. so in the recent ten years, PAS handset industry developed fast. It got succeed in Japan Taiwan and some other Asia place.The design of handset mainly contains base-band part, RF part, structure part and software part. In the design process, the four part acts each other. The base-band and RF are the hardware system of the handset. They combine with software. Then determine the performance of the whole handset. The structure determines the outside of the handset. The whole handset need to get strict test before producing in batch.In this parts design, the base-band is the core of the handset. It is the most important part of the handset. Other part design all have relationship with the base-band. The base-band chip is 88P88XX from Marvell in this paper. It is designed to use in PAS handset specially. It mainly contains ARM7TDMI and ZSP400. ARM7TDMI mainly used to process the digital signal, ZSP400 is used to process the RF signal.ARM7TDMI is one of general 32 bit ARM microprocessors family members. The ARM processor has the outstanding performance, but power consumption is very low. The gate quantity are also few. The design of ARM structure is based on simplified instruction computer principle. The ARM7TDMI processor use linears to get the process speed. The ARM system structure supports 7 kinds of process patterns: The user pattern, the quick severance pattern, the severance pattern, the management pattern, the stop pattern, the undefined pattern and the system pattern. This paper studies the base-band hardware system design of the PAS handset.It is a hardware system which is found on DSP. It extends a 64M flash RAM and a multimedia DSP processor AIT660G. which is used to enhance the multimedia function. AIT660G sustain handset photography, MP3 sound signal recording and playing, SD card extending and LCD interface.S71GL064A is a fold-type memory which is produced from Spansion Corporation. The aggregate capacity is 64M, inside of which contained flash memory and 16M false static state random access memory (pSRAM).AIT660G is a high integration, multi-function, multimedia processor. It is especially suitable to the mobile equipment and handhold equipments'picture audio installment. Such as handset, palm personal computer, PDA and so on. The biggest Superiority of AIT660G is on the inexpensive and high performance, small seals and the low power consumption. WM8731 is a low power comsumption three-dimensional multimedia digital signal decoder, the interior integrated an earphone actuate circuit. WM8731 is specially designed for the use in the portable MP3 audio frequency and the pronunciation player and the recorder. It is also suitable to use in MD, the CD-RW machine and the DAT recorder. The handset sets shoots uses OVWI2413 miniature photograph sensor from Guangzhou Daling limited company. it most supports 300,000 picture elements pictures in the photography. The SD memory card (the Secure Digital Memory Card abbreviation) is based on flash fashion. It is also called T card in domestic. It extremely suitable to use in emerging consumption electronic appliance.which needs restricted datasecurity, the storage capacity, the memory property and the environment request and so on.The paper discussed the outside circuit design of the handset base-band. It contains ring circuit, charge circuit, LCD circuit, PIM card circuit, motor circuit and keypad circuit etc. among them ring circuit also contain call ring circuit, Receiver circuit, MIC circuit and headphone circuit.The charge management chip uses ISL6294 from Intersil Corporation. ISL6294 is specially designed for the high accuracy linear lithium ion battery charger,extremely suitable to the low cost, portable battery chargers. Its has high accuracy pre-charge, the constant current charge, the constant voltage charge, the battery condition test, the charge finished lowly divulges, the charge condition instruction and the excessively hot protection and ultro-voltage protection and so on.Handset get series self-test about the base-band part circuit after the design complete. The test is use to make sure all the function part get to the standard. Test result shows that the handset working well, and get to the requirement of the handset standard. The design has reached to the top level in our country.