MEMO ROUTING SLIP 

REF ID:A6892 

NEVER USE FOR APPROVALS, DISAPPROVALS, 

CONCURRENCES, OR SIMILAR ACTIONS. 

1 NAME OR TITLE INITIALS 

•-~~~_....M~r_._...W"""'.F~·._.F~r~i~e=dman====-~~~~~-i-~~-• 

CIRCULATE 

ORGANIZATION AND LN~ONOOT DATE 

----· 2 

4 eclassified and approved for release by NSA on 

COORDINA· 

TION 

FILE 

INFORMATION 

NECESSARY 

ACTION 

NOTE AND RETURN 

SEE ME 

-~7-16-2014 ursuantto E.O. 13526 •-s-1G_NA_:ru-RE---1 -.. ..................... ..._....,; ...................................................... ~~~ ..... "'"' 

FROM NAME .ff.~ff.'f'et tengill DATE Tl July 54 

ORGANIZATION AND ~N lSKl TELEPHONE 

DD 1 f ~~"ao 9 4 REPLA<:ES NME FORM 94, 1 FEB ... wHlCK MAY BE USED. l~ GPO 
•PoREF ID:A68929 
Dr. Ing. Rud.olt Hell 

~ethod !or the S.CNt Tranamiasion or Xeuagea. 

In the tranaaiuion ot menage• it la trequentl.,- neceu&17 to maintain Ncreq, 

whether it ~ l.an,gu.age, a picture, or Moree oharacten. Thia aatter i• ot apeeial. 

iaportance in th• cue ot· wireleaa tranaiuion. .Nt:aerwa ..U.00 are knoMn ter 

aeeret traruitd.aaion or llNAgUt 

In telegraphic operations ror inatance the u.. ot cipher achinu tor the 

OC:ipbel"Mllt Of the text is the MR •t!ecti Te ae&nSe In tele)tbon1c operationa 1f1 th 

uplituda 90dulation the carrier !NqUne7 i• llOdUlatfM\ or a aide band reTarAJ. or -.1'9 

band tranapc>aition ia undertaken. Otten tU aesaage i• U.U tmintelllgibl.e b7 npe:r1.llpoaition ot inter!erin& frequencies. ~the TOiee !reqUC!CJ band aq be broken 

up into MTeral tNqU4NlC7 ranges ( IUb-handa} llltlch are tranapoaM and ued to "°"''' •t• 

the carrler trequenq. In thia vq the aide bands appear inte?"Cbal'lgM. In taea1•1Mt 

HCNC1 is achie'ftd b,- .,et.ematic change ot the qnchronia •f ~ pictlln ._. 

at. the senc;Hng and NCeiT!!ig at&tiona which C&UH8 a diatort!on ot the .iaage. In 

ao dol.n! the aage Mplitlldea are preHM'H, on:Q' the poei tioo ot the 1aage •l •anta 

with respect to one anot!wr is changed. It. bu &lao been propoMd to tl'*llDit the 

~ eleunta alterna~ u poeitiff and negative. In regard to unauthoriaed 

deciphensent ot the secret .. uage, t1te method.a ot apnch enciphenMD.t working 

v:ith transposition Of U:le ~07 a\lb-b&nU iJ safest. TbeM ðoda lioweYW all 

UH amplitude W>dtal•tion and do not Mk4t uae or the great tranaiuion adftntagN ot . . 

trequ.en07 aodul&tion. Seci-.t tacaiaile on th other hand uee no~ 

tranapoaitiona, despite their aucceaa 1n apeech encipherMnt. 

According to the under~ lct.a ot tlll.a 1nTention a pi.c• ot intorMticm, 1.e. 

language or a picture, 1• firat. !NqU8llC1' MOdulated and then tbe Mtboda ot 

,_ 

intlueneing rr.qu.nq tutli.Ar traa direct epeech enciphenertt u. emplo7ed~ Fqr 

this pu.rpou the trequ«tCT modulated .carrier ia broke lip vithi!l tb• ran&• or the 

t'nqlSency Utt (~ub) into partial trequencT ranges (nb-banU) anct these 

partial r&ng•• are enciphered. Por inat.Mee, tbs partial. . .raqea can k :1.11Wrchanced. 

according to a kq in continuou9 fashion using wll knowD MAH. Uter eocipberaea.t, j 

i· 

tba wb-banda are q&in united into a tNqUeney band ,are. either traaaitt.4tel diNctq ~; 

l 

EOHFIDEHTIAQ 

,_'.~I ' •' 

. .-.... ~ 

- -._;_ 
to tlle receiYer or are t.n.naforud into an uplitlide modnl&ted band to render 

uaatMrind deeipheraent aore ditticult and then tranaittecl •. Tranainion mq be 

ewr lliru or ~ virel.e••· At the-. neebi.ng encl the -. operations follow in ft!Yerm• order, 

~ th• Muage ia ag&iii deciphered• 

The ue of f'!'eqaMC7. modul&t.ed aub-b&nu bu, in &ddit.ion to the famili&r 

dYantages of trequmcy"llOdulation, in partiClll.&r l•e aens1t1'91.V to interference, 

tke A4h'aatage tat the a.plitudu ot th• aub-banda are~ great and constant at . . . ' 

-tll• tiM ot eneipMl"Hllt 80 that the interchange ia more _r-M117 accoapli~ed· rus 

. •tho4 i• eapeei&lq t&'tOrable tor secret. tace1mle tranaiasion. In contrast to •thocla 

~hitherto tor ..cret tacaillile, the amplitude itaelt, which- repreaent• the cont.nt 

ot the p ict.ure, 1• treated with a HCUN- encipberment proceaa 1n the round about ....,. ~ 

, . . . . . 

~1' aodnlat1on, vhe~ the ..,Utude of the !Nquenc7 ~ted aub-banda iwaina . '• . ·. 

conat&nt 1a qit• or vaeying picture aaplituclea. sinee it is aho poaaible to •ketch --

tll• pict.ve dot lv' dot in the receim, th.- till•• ot tile n.betitution ot the aub-banda 

~be plMM Detwm the ncording o~ the picture elaent• and thua be blal'lkeri out._ 

(a.augeblendet). 

. ' 

In the 11J.ut.rat1on is·shown a block wiring di&gru or the-encipherment procedllra 

in principle. Proa a· source l the aessaga trequeney band (language or picture) C011U · 

na th• apliti•r 2 to~ modulator 3, in which its trequenq aodulate• the carrier 

- - : . ' - fNCf1ClC7 n.pplied bJ' ~Ulator 4. Filter Sis pel'Jdlleable ~-tor· the range ~t th• 

'' trequnq l1A (1requenshub) ot _the c~er waves and cv.ta aq th8 original meauge ·- '· 

trequnq" band. 

The trequcc7 band llhicb 1• peraitted to Paa• 1• broken up into tour aub-barda, let : , . . ' . 

•• aq, b7 tov tilters 6, 7, S, &nd 9, which are interchanged in fM1 liar fashion iri 

' ' ' \ 

\ 

07 stage 10. After eactpberunt, the sub-banda are again combined to tona a f~·' · . \' ', - ' •, 

' ' 

Nncl and came rla selector switch 11 directq into .-nder at.age 12. Switch 11 can . ·, .... 

be eo tllJ:olm that the rr.quene,. band composed ot th8 trt.naposed aub-b&nds i• ' ' 

·l"- tranatormed in arrangement lJ into amplitude modulation and onJ¥ then reaches the,_ aending -· 

.\ 

~ge u. ··.-- ~ here the modulated carrier ia comtucted to the line l4 or to an 

ant9111'l& and ao to the receiTI.ng station~ 
l. Met.hod tor NCret. t.ranaiaaion of uaaages, in particular 

tor the MONt tJ'IMlli•aion of pictvu'., characterised by ti. -rut. -

t.hat tH frequ4'U7 band ot a carrier •w, whic~ i• freq_unc7 

--lated with the ••aaa•. i• broke up int.o -MYel'81 au~bandll 

and thea• llUb-b&ttda are ·enciphered. 

2. Mat.hod according to Claim l, characterised by th• tact 

~t. the part1&l. i'NqllenC;r ran&•• &l'tl acrambled &ccord.i.ng t.o & b7• 

3. Hat.bod .cool"ding t.o Claw l and 2, cbancterised b7 t.he 

tact that ti. enciphered partial ~c7 ranges are COllblmcl 

into & ~ band ad tranaaitt.ed. 

4• -.t.bo4 aeco~ to Claiu l - '• char&ct.erised b.r t.he 

l&c-t · that the t'Nquenc7 band. zad• up or encipheNd partial freque'ICJ' 

Dada i• t.ranatormed. belore trusmiea1on into an aplitude 

modifie4 carrier. 

eo11i=10ErtjTIAQ 

' 
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REF ID: A68 92.9, .•. ~ 

I\. 

t,." · . EOt1FIDE:ttjTi.~Q