The address code is the number set when the product leaves the factory, which is used to distinguish different equipment, just like the identity number of the machine.The address code is generally 7 digits.Digital information machine and voice information machine use address code.The address code of the digital information machine can be changed manually. Each machine can set up to 7 address codesoperationSee instructions.The voice message machine can be set with 7 address codes at most, and each address code can be 7 digits. It can not be handwritten, but can only be professionalCoderWrite code or change.
In the code division multiple access communication system, the address code refers to the code sequence that can distinguish different users, and actually has the function of spreading spectrum.The choice of address code directly affects the capacity, anti-interference ability, access and handover speed of CDMA system.The address code should have a sharp autocorrelation feature to ensure that the signal has a high signal to noise ratio after the address code despreading, and at the same time, the cross-correlation is minimal (mutually orthogonal) to ensure that the interference between code sequences is minimal.In order to overcome multipath fading and achieve effective and reliable communication, address codes should approach the statistical characteristics of white noise.
The voice message machine can be set with 7 address codes at most, and each address code can be 7 digits. It cannot be written by hand, but can only be written or changed by professional code writer.[1]
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The automatic addressing system adopts CRC with strong error detection and correction capability based on strict mathematical theory in the design of communication codeCyclic redundancy check code。FSK data encryptionModulatorIt will be valid at the sending endInformation codeMeta meridian function is mapped into a groupError correcting codeSent, two-way centralized by automatic addressing at the receiving enddistributorThen reflect and emit an information value, so that if the reflected information value is different from the constant value of the two-way allocator in the automatic addressing set (the so-called constant value is the value generated by thesystems softwareOne user with uniform number corresponds to one address code, and one address code corresponds to one port, and the address writer writes the information code to the user end automatic addressing centralized bidirectional allocator), then it is judged as error code and does not control the viewing status.Because onSymbolIn the design, there is a complex function mapping relationship between each effective code element and error correction code, so any missing code and error code caused by interference and other factors are extremely difficult to meet the same function mapping, so that the uncontrolled and error controlled communication is almost zero, and the error of simple error correction operation (such as odd even test) is overcomeControl rateThe weakness is still high.[1]
MultiplexingMultiplexingTechnical Term, in the absence ofAmbiguityIn this case, "multiplexing" can also be called "multiplexing".Multiplexing usually means transmitting multiple signals ordata streamProcess and technology.Because multiplexing can integrate multiple low-speed channels into one high-speed channel for transmission, it effectively uses high-speed channels.By using multiplexing, communication operators can avoid maintaining multiple lines, thus effectively savingoperating costs 。[1]
Time division multiplexingIt is characterized by that the high-speed channel is divided into multiple channels according to timeTime slotIt is used by multiple low-speed channels in turn. Within a time slot, only one low-speed channel can occupy high-speed channel resources.[1]
The characteristics of frequency division multiplexing are: multiplexingMultiplexerThe signals of each low-speed channel are modulated and distributed to each frequency band of the high-speed channel, and then superimposed to form the signals transmitted on the high-speed channel,ShuntGenerally passedBandpass filterSeparate each frequency band and forward it to the corresponding low-speed channel.stayOptical communicationThe technology of multiplexing according to different wavelengths of light waves is calledWDM（WDM）。[1]
Space division multiplexingIs characterized by: using multi antenna technologyBeamformingTechnology aims the signal at a specific transmitting source or receiving station to receive or transmit.Through space division multiplexing, multiple transmitting sources or receiving stations can use the same frequency at the same time.In actualcommunication engineeringSpace division multiplexing is usually used in combination with other multiplexing technologies.[1]
Code division multiplexingIs characterized by:spread spectrum communicationTechnology, each low-speed channel can use the same frequency to communicate at the same place at the same time, and different low-speed channels use different address codes to multiplex the entire frequency band.[1]
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storageThere are many instructions or data stored inStorage unit。Each storage unit has an address number, that is, an address code.Address NoIncrease from small to large in order to access or store the storage unitBinaryThe information is called the content of the address. You can search and access the content in the storage unit according to the address.[1]
Address codes usually specify participationoperationThe address of the operand of the.According to the fact thatOperandsThe address number X, which can be called an X operand instruction or an X address instruction.Current two address and one addressInstruction formatUse most.[1]
An address instruction is often called a singleOperandsInstruction.(AC) OP (A) → AC[1]
Two address instructions are often called doubleOperandsInstruction, which has two address code fields A1 and A2, respectively indicating that the two numbers involved in the operation are in memory orArithmetic unitGeneral registerThe address A1 is also used as the address for storing the operation results.(A1) OP (A2) → A1[1]
