|
Архитектура Аудит Военная наука Иностранные языки Медицина Металлургия Метрология Образование Политология Производство Психология Стандартизация Технологии |
|
|
Архитектура Аудит Военная наука Иностранные языки Медицина Металлургия Метрология Образование Политология Производство Психология Стандартизация Технологии |
Abbreviations Used in Traffic Handling
AA all after AB all before you ADR address BN all between CFM confirm CK check DLD delivered GBA give better address MSG prefix to radiogram NIL nothing; I have nothing for PBL preamble REF refer to SINE opr's personal initials TXT text VC prefix to service message WA word after WB word before WD word
Examples Of The Phillips Code
Words were cut to their "backbone", leaving only the letters that carry the brunt of their pronunciation. See the list below for how this was done. Abbreviated words were modified by, e.g., adding "d" for the past tense of verbs and "g" for -ing; "s" was added to nouns for their plural; some words added "b" forable. A couple of simple examples of text are given here.
Example of 188 letters reduced to 116 (?) 61.7%:
"The decision could mean the end of the unprecedented two year custody battle, the first in the United States in which a surrogate mother was taken to trial for backing out of an agreement to turn over a child she bore under contract."
AB about ABV above ADZ advise AF after AG again AJ adjust ANR another AR answer AX ask AY any AYG anything AYM any more B be BC because with BD board BF before BH both BK break BN been BTN between BTR better C see CCN conclusion CD could CK check CKT circuit CL call CLO close CLR clear CMB combine CNG change CT connect CU current CY copy D in the DD did DT do not DUX duplex EMGY emergency EQ equip EQPT equipment F of the FD find FJ found FM from FR for FT for the FYI for your information G from the GD good
GG going GM gentleman GTG getting GV give H has HD had HM him HR here, hear HS his HV have HW how ICW in connection IM immediately INVG investigate IX it is KW know LV leave M more MK make MSG missing MSJ message MSR measure N not NA name NF notify NI night NR near NTG nothing NUM number NV never NW now NX next OD order OFS office OP operate OTR other OV over PGH paragraph PLS please Q on the QK quick S send SAF soon as feasible SAP soon as possible SD should SED said SES says SM some SM somehere SMG something SN soon SNC since SPL special STN station SVL several T the TGH telegraph TGR together TI time TK take TM them TNK think TRU through TS this TT that TTT that the TW tomorrow TY they U you UN until UR your VY very W with WD would WG wrong WH which WI will WIN within WIT witness WK week WN when WO who WR were WS was WT what WY why YA yesterday
A Few Useful Z- Signals
ZCG local receiving conditions good ZOK we are receiving OK ZVF your signals are varying in frequency ZHC how are your receiving conditions?
You will notice that these signals are much easier to remember than the Q-signals. The two letters following Z- are suggestive. (QST 1943 No p. 63)
In 1910 some wireless abbreviations were: Chapter 28 Letter Frequency Counts -International Morse-
The letter frequency counts (left-most column) are taken from one of the common books on cryptanalysis, based on number of occurrences per thousand of normal English text material. Each character is analyzed ("structure") into units, 1 for minimum signal duration (one dit), 111 (three units duration) for a dah, and each equal unit of silence denoted by 0 (zero). The required three units of silence separating each character is added (000) to each one below.
Freq. Letter Structure Units Total
1000 Ave. Structure length 11.23 Ave. 9.07 9076
From the above, if we take five times the above average letter length and add the space required for word spacing (seven total or 0000000) we arrive at the normal English word length as 5 x 9.076 + 4 = 49.38. This is just a bit less than 1% shorter than 50 units per standard word. (By contrast, a random five-letter group averages 60.15 units. This is 20.3% longer than normal
Comparing these calculations will show some of the reasons why receiving speeds vary with the kind of material being sent.
As a matter of interest, we list here the letters from the shortest to the longest by the number of units (less letter space) -- notice that all lengths are odd numbers: 1 - E; 3 - I, T; 5 - A, N, S; 7 - D, H, M, R, U; 9 - B, F, G, K, L, V, W; 11 - C, O, P, X, Z; 13 - J, Q, Y.
Foreign Adaptations Of The International Morse Code:
For the Original American Morse code:
Chapter 29 The Koch Researches
The obviously extensive researches of Ludwig Koch, psychologist at Die technische Hochschule, Braunschweig, Germany, reported in Jan-Feb. 1936 (see Sources), seem to be virtually unknown outside of Germany. His goal was to discover the most efficient way to teach the Morse code to prospective radiotelegraph operators to meet the International requirements for commercial radio operators. These requirements were:
· send 100 words in five minutes, · copy a 100 word telegram in five minutes, and · copy 125 words of ordinary text in five minutes, one word being reckoned as five letters
Koch's researches involved: determining what competent operators are doing, examining teaching methods in current use, then devising better methods, and testing them in actual classes. His conclusions and recommendations seem to be the earliest real research into how best to teach the Morse code. They agree on the whole with the best methods of today, and may offer some further ideas of value to us. They are summarized here.
Tests to Determine What Competent Operators Are Doing
Sending Tests
Below about 10 wpm the only operator who closely conformed to standard timing was the one who had visually learned the code. The three others deviated considerably from "standard" timing. At 5 wpm these deviations were appreciable:
· the dits were too short, · the dahs tended to be longer than 3 times dit length, and · the spaces between characters were too long.
However, spacing between the components of a letter was almost perfectly equal to their dit lengths.
At successively higher speeds this situation changed slowly and somewhat irregularly until by about 10-wpm character rate all four operators were forming fairly accurate patterns of sound (nearly to the International Standard), except that the letters themselves were somewhat faster and the spaces between letters were somewhat longer than standard. By about 12-wpm all sending had become quite consistent with the standard. (Only the well-known individual peculiarities of sending by hand were obvious. At 10-wpm and above these deviations were always very small.)
The three operators who had learned by sound obviously showed no real sense of sound patterning (Gestalt) at these very low speeds: no sense of unity, but rather just a series of separate elements strung together. Only by about 10 wpm were the code characters now felt to be entities of sound in themselves, patterns which were clear-cut in each operator's mind, no longer shattered elements, disjointed parts.
Receiving Tests
At about 5-wpm these experienced operators hardly recognized a single character correctly! At 7-wpm only 40% to 60% of the letters were correctly identified. At 10-wpm all operators were getting about 95% correct. By 12 wpm all of them correctly identified every character. Test number Two: - Here the length of the spaces between the letters was doubled. This time the operators recognized almost all letters correctly at all speeds. That is interesting. From these tests it was concluded that experienced operators recognize a code character by its overall acoustic pattern (Gestalt), and that this pattern stands out clearly only when sent at a minimum character speed of about 50 characters per minute. At lower speeds it is heard simply as a disjointed series of signals. -- Koch concluded that these operators could recognize the too-slowly sent letters only when letter spacing was doubled, because this increased interval gave them time to integrate the sound and mentally speed it up to where they could recognize it. (A beginner would not have the skill to do this.) The operator who had learned from a printed code chart apparently formed better-proportioned characters at very low speeds because his visual mental picture was so strong. However, the price paid for this was that it limited his maximum speed of copying: he could barely meet the minimum requirements - a marginal operator. (See below.)
Analysis And Criticism Of Previous Teaching Methods
The faults with this system are: · To begin by learning visual symbols creates a useless detour · Slow sending destroys any unity, or coherent sound-patterning · The disjointed signal doesn't meet our need for a sense of unity · Learner can hardly help counting the dits and dahs · the long spaces between letters distract his attention from listening by: · encouraging him to think and try to put the shattered parts together to make sense of them, a shaped unity, (Gestalt), or · guessing what may come next · at each increase in speed everything sounds different, and he virtually has to start over again. In short, the student is sidetracked and severely penalized all the way along: needlessly translating from bits and pieces of sound to try to put it together into a meaningful whole, then converting that to visual form and then finally to the letter. The "Sound-Pattern" Method first introduces the Morse characters to the student at a character speed fast enough for them to be perceived as an acoustic unity (Gestalt), but with wide spaces between the characters. However, the student has usually already visually mastered a code table or is encouraged to do so as he learns.
Unfortunately, visual mental pictures are usually very much stronger and easier to recall than auditory sound patterns. Thus the student tends to convert the signal pattern he hears into the corresponding visual representation, break it into its component parts, and then finally into the letter. This complex action tends at least partially destroys the wholeness of the acoustic impression.
This series of actions is encouraged by the long pauses between characters, giving adequate time for thinking, speculation and the cumbersome translation processes. With increasing speeds the pause time becomes too short to go through all this, and so the student gets stuck below or around 10 wpm, just as with the analytic method.
So this method tends to suffer about the same faults as the analytical method. Both generally lead directly to that troublesome plateau at around 10 wpm, where the distinct change in perception from bits and pieces to coherent unity of each signal occurs.
Analyzing these methods, two classes of errors can be seen:
· Errors which hinder the building of a sense of acoustic unity · Detour through an optical symbol. · Disintegration of the acoustic form of the character. · Errors which prevent going directly from acoustic impression to the letter: · Thinking about the signal during long pauses. · Guessing what may come next. · Converting or translating from sound to visual and from visual to the letter · Converting or integrating into a total rhythm pattern.
The remedy is obviously to eliminate all visual references and associate the sound directly with the letter, to send fast enough from the very beginning so that coherent sound patterns are immediately sensed, and to eliminate non-normal spacing between letters.
|
Последнее изменение этой страницы: 2019-04-19; Просмотров: 212; Нарушение авторского права страницы