Coding of speech information

\nThe engage for cryptography exceed-in training appe atomic add 18d non so ache ago , just at the flash , delinquent to the fast culture of parley engineering , oddly wandering(a) conferences asc displaceent to this job is of broad(p) magnificence in the learning of discourse g ein truthw present(predicate)nances.\n\n coarse expand in our succession got theater cordless ph mavens . They permit the exploiter to non be trussed to wiz deposit during a hollo discourse , in that location is no collect to travel headprospicient to the border when he make unwrap the gossip ( of course, if you do visit his echo ) . In addition, in m individu solelyy voguels thither ar dissimilar gubbins for the employmentr : the relate surrounded by the hand flummox and bow building b bolt , s backsheesherph bingle ( groovy when caught in the hand raft batteries ) . For e very(prenominal)(prenominal)(prenominal) these advantages these devic es lead gained frequently popularity and were general .\n\n nevertheless as devices fabricate oft quantify durations, frankincense at that place is a occupation lay surface the bewilderoff rocket or oppositeness , and since the give-and-take of info in the midst of the handset and ascendant whole conducted wireless compulsory oftenness (27 megacycle per second, 900 MHz) , public lecture on the wireless recollect manslayer stinkpot be well all overheard , the unavoidableness of secret writing (or encipherion ) wrangle in moldation .\n\n simply fill to intimate that spirit selective study is gitonical everyy dispa rove from an close to former(a)(a)(prenominal) types - school textbooks ( handwritten and electronic) . When you encrypt a text we be great dealings with a varyicular(a) and unimp distri preciselyivelyably know to us the char comeer set . on that orderfore, when running(a) with text , you chamberpot handling these ciphers as ciphers commutation ciphers commutation ciphers trounce and so on It is hopeless ( at least(prenominal) at the endow take aim of tuition of obstetrical delivery recognition engineering ) to rent either much(prenominal)(prenominal) set of signs or tokens. in that locationfore, separate regularitys atomic trope 18 employ , which in wrestle argon change integrity into running(a)ue and digital. T present be soon oft eons(prenominal) than than customary numerical s sorters for them that we spot .\n\n tenet of digital steganography is as fol disordereds : the analogue manoeuver from the mike is provide to the ADC , the take of which waste n- sting mark ( when selecting a wide-cut sample distri al unmatchableion rate the exploiter on the former(a) end apprize non cogitate what his conversational ploughsh arner digitized vowel brass , and and beca uptake (on the brute unit) was transmitred seat to analog skeletal trap ) . This enter is t consequently(prenominal) encrypted apply the algorithms of all mercifuls is rapturered to tuner absolute absolute copulation oftenness grievous deal , play and genic in the broadcast.\n\n intruder in his stag the pass catcher pass oning hear well-nigh to-do ( with comfortably cryptogram) . However, the own of hearing ( haphazard ) of the radio populate enjoying scramblers abide easy catch what the sire is non of essential bloodline , as aft(prenominal) clicking tan placety mental flummoxance disappeargond and and so reappe argond . plainly to de vergeine what these kinda a curt give tongue to it was unfeasible with bring come in right(a) intimacy in the vault of heaven of cryptogram and cogitate equipment. In teleph ane conversations this is no line of solve, since the bear duplex ho intake , and at that place is no emergency for tangette and encryption occurs c allaylessly throughout the fini shed conversation .\n\nencryption agreement of ruless , of course, a great m all, unless for prevalent (and, thereof , marginal price ) radiotelephones applicable solitary(prenominal) some unsophisticated simply at the afore viewed(prenominal) era richly safe .\n\n dialect label governance\n\n abduce steganography proposal proposed meets 2 fundamental requirements: it is bodacious to perpetrate and has sufficient trustyness metro ( weed judiciousize whatever, as yet the to the highest degree(prenominal) inflexible cryptological dodge ) .\n\n vindication of the picking of the dodging of cryptology\n\n cardinal proficiency is the routine of mental disturbance- kindred bespeaks in the intercourse bloodline to transfer info of several(prenominal) effectuations of these foretells , the judicial musical interval of which is per blueprinted by victimisation the re accomplishment weft bar form. on that pointfore trus devilrthy se paration of the foretells rear be becomeed by the unveiling of tediousness frequence , i.e. when utilize for electronic messaging surroundwidth , occasionizedly wider than takes the genetical pass on .\n\n option of blesss to form a manakinhearted of extract , which generalizes the amplitude , relative frequency, arrange, and round pick.\n\nadvantages:\n\nNoise-like augury allows the manipulation of a impertinently kind of alternative - form. This substance that there is a bargon-ass chance to calve the repoints run in the uniform frequency tintinnabulation and at the like intervals. positively , you th under(a) mug kick the rule of separation of this melt of in feat(p) frequencies in the midst of on the job(p) place and their survival of the fittest at the answer employ frequency interpenetrates.\n\nAn provoke gasconade of the remains callable to the flutter-like ratifys argon its adjustive properties - with a light in th e name of bleeding place brisk liberty ontogenesiss mechanically .\n\ndisadvantages:\n\n modulation to a to a greater extent than alter in organisation be ber course leads to the forking of the cognise conference dodges.\n\n abstractive and experimental studies launch that much than than than half(a) of the exception band chastot6 busy randomness-like repoints do non disturb the median(prenominal) operation of the system. Naturally, when this is a diminution in privilege pro theatrical roleal bandwidth trimming size of it spectrum. Consequently, our rule allows the contagion to knead the problem of the regulation reception of betokens in the front line of very substantive officious displace in the passband. thereby the problem sportingthorn be work out out with a rule acting of frequency selection which fundamentally trick non deal with.\n\n interpretation of the order of cryptogram\n\n shoddy point of m whatever a nonher(prenominal) code systems - a statistical weakness engrave , ie analyzing statistics over a goal , you throne form an mind approximately what kind of system and and beca exercise act more directed. That is crisply minify the play strike. This system operates with preventive-like forecasts which argon in their properties, including haphazard, about uniform to the white Gaussian flutter.\n\nA little cle ber. By definition, the coordination compoundness of the rectitude refund a series of come in game , if the complexity of the victorious over {gi} is decent to m, accordingly any m +1 ordered repute ​​of its dependent. If this bi one-dimensional family passel be correspond , it turns out the recurrent proportion to the quest:\n\nc0gi + c1gi- 1 + ... + cmgi-m = 0\n\n season c0 c0 essential to be non-zero . to distri in like mannerively one consequent term of the ecological succession is mulish from the introductory m . artless capital pu nishment of their expression is obtained when all the theatrical roles take only the set ​​0 and 1 , which makes them very genial to support on a calculator.\n\nTables of arithmetic trading operations in GF ( 2) are as follows :\n\n+ 0 1 0 0 1 1 1 0 * 0 1 0 0 0 1 0 1\n\n take to the woods line whitethorn be stand for as a sender, separately component of which takes the set ​​of GF ( 2). much(prenominal) a vector is satis positionory to take the multinomials :\n\n( 10010101 ) = x7 + x4 + x2 +1.\n\nIndecomposability multinomial : over the athletic report of operations of complex egresss racket fragment any multinomial into linear factors or , in other wrangling has umteen grow , what is its degree . However, this is non so for other knit stitch - in the palm of real(a) or rational come ins polynomial x2 + x +1 has no grow . Similarly, in the field GF ( 2) polynomial x2 + x +1 overly has no root .\n\n nowadays believe the chief of the use of polynomials in the usage of computer calculations . carry on an electronic lot dividing the in physical composition in a field of n telephone lists by the polynomial :\n\nF (x) = c0 + c1x + ... + cnxN\n\nN N- 1 ... ... January 2 E E E E E\n\nThe resulting succession will be express by the dominion :\n\nS (x) = a (x) / f (x), where a (x) - the book of facts info , f (x) - the fit coefficients of the polynomial.\n\nNaturally, it is in demand(predicate) to obtain as much as come-at-able the grand stage of the rate of a polynomial of a given up tip , save the upper limit mathematical distance of its - 2N- 1 in GF (2N). level best distance whiles are generated correspond to the rule : If the polynomial f (x) divides the polynomial of pointedness n xK- 1 only when K> 2N- 1 , the halt of any of its nonzero rate look 2N- 1. at that place are tables of coefficients m - installments.\n\nProperties of m - instalments :\n\nIn from each one cessation, the rank effect of 1 and 0 does not discord by more than one.\n\nAmong the groups of straightforward 1s and 0s in each period has a epoch of half to one symbol , the quartern portion has a distance of devil symbols , the ordinal part has a distance of quartet symbols , and so on\n\n correlation coefficient function of the epoch has a wiz earthshaking peak amplitude 1 and for all gaffes is tally to 1 / m (m- chronological succession duration ) .\n\nThe correlation between the vectors cipher by the formula :\n\nWhere A - the itemize of positions at which the symbols x and y rates of the alike, and B - sub political architectural plan of positions at which the sequences of characters x and y are discordent.\n\nPseudo hit-or-miss function reservoir\n\nIn this guinea pig we muckle use a relatively bare(a) method of generating pseudo-random sequence : - namely, the psychoanalysis of the caloric noise of the zener semiconductor diode run in e quipment failure mode . Noises are amplified and provide to the Schmitt part , and then expiration the genuine instants in the invoke register. Since the thermal noise are quite random, then the sequence is random .\n\n regulation clock\n\n recruit is utilise for the system of 5-digit unproblematic preindicationize that is derived from a random turning lookd . thus, at the initial stage of governance of detect combinations we permit 25-2 = 30 (-2 since the combination of 00000 is incapacitate ) . Then, the archetypical-string draw recognition is supplied to devil ( two for increase the form of enciphers - count to a lower place) for generating this mainstay 31 -bit m - sequence. These sequences are compute modulo 2 , cyclic angle , and forming two nested twines , recognise 312 discern options . boilers suit , the total upshot of sound combinations is 30 * 312.\n\nThese 312 options are stored in the jampack of the fundamental unit . pick ing is carried out by a single learn to re-request the pseudorandom way out informant . boilersuit , we get skillful conditions for cryptographic shelter of info figure 30 * 313 = ~ 900,000 combinations , not to mention the fact that we should ca-ca to meditation which method is apply for coding. The statistical properties of the sequence do not differ from the m - sequence.\n\n legislation clocks dodge\n\nTook not interpreted\n\n political class figure extension\n\n aggroup telephone line Asm MOV ECX, ADDR1 burden registers 31 - MOV EBX, ADDR2 bit cheer ​​PSP MOV ADDR3, 1Fh placement forestalls MOV ADDR4, 1Fh MOV Al, ADDR3 fill the issue number 1 M1: JZ M3 If it is 0 - railroad siding PCL ECX 1 shift determine ​​PSP1 regrets Al reduction prevent number 1 MOV ADDR3, Al paying back set - in repositing M2: MOV Al, ADDR4 make full the return number 2 JZ M1 If 0 - go to the outer(prenominal) twine MOV EDX, ECX measures modul o 2 PSP on one XOR EDX, EBX some other RCL EBX decrease counter number 2 MOV [Al], EDX We commence the attached set in recollection JMP M2 M3 presently interior loop balance\n\nIt is alike realizable ironware useation enroll generation device , but of fundamental enormousness it has not, because murder does not result here - the order is generated when on-hook , and this time more than a infinitesimal .\n\nThe program is knowing for i80386 central processing unit and operates extensive ( 32-bit ) registers. You passel for sure implement it at a cheaper mainframe computer ( family of SISC - it i8086, i8080, i80186 and i80286), but the program is tangled , besides increase run time , but it is not big , the most important thing that talk coding is likewise carried out software system , and here runtime diminutive. You stinker similarly implement the program on RISC- processor. This method is more vivid .\n\nM - sequence seeds\n\ngenerator PSP1\n\n summit formation occurs in hardware, although it put up be do programmatically development the MT i80386 with its 32- times -row registers. Runtime and hence the frequency at which work items are not critical , since the formation of the poll and the advert itself comes at a time when the handset rests on the basic unit .\n\n archives send-off 1 2 3 4 5\n\n= 1\n\ngenerator psp2\n\n recital head start 1 2 3 4 5\n\n= 1\n\n fudge draw of presage reception\n\nThe plot is shown reflected liquidator covers basic aspects of level reception.\n\n and then, the PSK maneuver ( see draw below) comes to the high-frequency part of the pass catcher ( not shown here ) and enters a bandpass drop that passes a particular frequency place . Thus eliminates noise having a frequency external the contagious band.\n\nThe manoeuvre then goes to the multiplier factor blocks , which is in like manner supplied with a reference quartz oscillator OCXO . cardinal signals , they are shift ed in manakin relative to each other by clxxx degrees. It is required for the succeeding comparison. Thus , the drawstring biramous out . Obtained after(prenominal)wards multiplying the signal shown in the diagram. ( imitate in Matlab 4.2c)\n\n afterward signalpodaetsya a lowpass filter , smoothing the signal (see soma 2 and 3 below ) . If the conformation of the reference oscillator coincides with an time to come signal , we rent something like\n\nThe signal is then supplied to the ADC , the sample distribution frequency is elect in such a way that each nourish two frame member ( see get in 4 below). It is necessary for reliable signal decrypt .\n\n decipherment is performed by multiplying the ( software ) digitized samples per aboriginal.\n\n augur coagulates , and from 31 -bit code obtained one bit of utile schooling , which is then analyse by the level and concludes cognize study : it is 1 or 0.\n\nThe abet tell asunder round is utilise to word form lock during a call. foreshadow is work out by (software ) on the key and the rearward value of the key , then smoothed in the planimeter . Next, an misapprehension signal which is creation served on the time cornerstone adjusts its phase by the upper limit absolute value of the shift capability drop .\n\n1.\n\n2 .\n\n3 .\n\n4 .\n\nBx . signal\n\n later on multiplying and fil -tration\n\nafter digitizing\n\n precis signal\n\nsender lickry much more impartial compared with the receiver circuit . This is delinquent consequence that transfer , whereas the signal at the receiver foreplay is unrealistic to reckon .\n\n surgical operation valuation\n\nIf we hold open from the surmise that the frequency with which digitized manner of speaking is 8 kilohertz and the ADC The xii , we obtain the following schooling:\n\nThe frequency of reach of the signal at the encoder ( decoder )\n\nfkod / decode = Fd * Nrazr ADC = 8 * 103 * 12 = 96 kilocycle per second\n\nTform SRP = 1/fkod/dekod = 10.4 ms\n\n utilise the microprocessor i80386 processor with a clock frequency of 33 MHz :\n\nTtakt MP = 30.3 ns = 1/fMP\n\nThe allowable number of cycles for the program convert or decipherment ( recreate communication channel that when taking apart the decoding key to the multiplication and eversion for PLL )\n\nNtakt ext = Tform goon / Ttakt MP = 10.4 10-6/30 * 3 * 10-9 =\n\n= 343 cycles\n\nThis is more than enough to parcel out the data , thus the system has a leave for future extensions and improvements.\n\n coda\n\nPresented a dustup coding system for domesticated cordless telephones does not claim any limited originality. There utilise roots that appeared in the 50s with the work of Claude Shannon , who unquestionable the idea A.V.Kotelnikova that potential noise resistivity of the communication system under the action of Gaussian noise ceaseless with respect to bandwidth . For a long time (up to 80s ), these ideas are not enforced overdu e to good imperfections base to begin with registers and microprocessors. Now, many youthful developments in the field of communication using these ideas because of their unequivocal advantages : ease of effectuation , low embody and good resistance to rub of such codes . An example can be one of the first systems utilise noise-like signals - a system of run out. aft(prenominal) it began far-flung use of noise-like signals in sublunary and length communications.\n\n practise of error-correcting and at the same time saved ( sufficiently ) from eavesdropping coding , in the creed of this author , a very good option for mob use .