Morse Code
As stated above, Morse code is the first alpha-numeric code used in long- and short-distance electrical communication systems. This was in wide use in wired and wireless telegraph systems. Till recently. Since telegraphy has been replaced with modern computer communication systems, Morse code, at present, has disappeared from many practical communication systems.
Features of Morse Code
• Morse code makes use of two signaling conditions known as the dot (●)and the dash (─), respectively. A dot is the shortest duration between two consecutive knocking sounds. In the modern context, a dot may be thought as binary 0 (or, 1). A dash is equivalent to three dots and may be thought of as binary 1 (or, 0) in the modern context. Combinations of dots and dashes are used to represent alphabets, numbers, and punctuation marks.
• To represent letters, numbers, and punctuation marks, combinations of dots and dashes are used.
• Dots and dashes are assigned to represent an alphabet or number depending on the probability of its usage in a given language. For example, e is the maximum used letter in English words, with a probability of occurrence of 15%. Hence, it is assigned the shortest symbol, viz., a dot.
• In Morse code, letters are assigned with symbols of length ranging from one to four. Numbers are not as frequently used as letters and hence they are assigned with symbols of length equal to five symbols. Punctuation marks have the lowest frequency of use, hence are assigned with 6 symbols each.
• The interval between individual symbols representing a given letter is fixed to be of one dot duration.
• The interval between letters belonging to a word is equal to three dots.
• The interval between the words of a given sentence is fixed at seven dots.
• Since the length of the code corresponding to each alphabet or numeral depends on the probability of its occurrence, Morse code is considered as a highly efficient code.
Typical Examples of Morse-code Symbol Assignments
Table 1.14 shows some examples of symbol assignments in the Morse code system. As shown in the table and stated earlier, the number of bits (i.e., length of the codes) assigned to encode letters vary from 1 to 4 bits, depending on the probability of their occurrence. Similarly, numbers, which occur less frequently than letters in languages, are assigned with a length of 5 bits each. In the same way, punctuation marks, which are the least-frequently occurring entities, are assigned with 6 bits each. It may be noted that use of Morse code has become very rare; yet its principles still remain very fresh in the sense that it was the first systematic study on coding languages based on probability theory.
As stated above, Morse code is the first alpha-numeric code used in long- and short-distance electrical communication systems. This was in wide use in wired and wireless telegraph systems. Till recently. Since telegraphy has been replaced with modern computer communication systems, Morse code, at present, has disappeared from many practical communication systems.
Features of Morse Code
• Morse code makes use of two signaling conditions known as the dot (●)and the dash (─), respectively. A dot is the shortest duration between two consecutive knocking sounds. In the modern context, a dot may be thought as binary 0 (or, 1). A dash is equivalent to three dots and may be thought of as binary 1 (or, 0) in the modern context. Combinations of dots and dashes are used to represent alphabets, numbers, and punctuation marks.
• To represent letters, numbers, and punctuation marks, combinations of dots and dashes are used.
• Dots and dashes are assigned to represent an alphabet or number depending on the probability of its usage in a given language. For example, e is the maximum used letter in English words, with a probability of occurrence of 15%. Hence, it is assigned the shortest symbol, viz., a dot.
• In Morse code, letters are assigned with symbols of length ranging from one to four. Numbers are not as frequently used as letters and hence they are assigned with symbols of length equal to five symbols. Punctuation marks have the lowest frequency of use, hence are assigned with 6 symbols each.
• The interval between individual symbols representing a given letter is fixed to be of one dot duration.
• The interval between letters belonging to a word is equal to three dots.
• The interval between the words of a given sentence is fixed at seven dots.
• Since the length of the code corresponding to each alphabet or numeral depends on the probability of its occurrence, Morse code is considered as a highly efficient code.
Typical Examples of Morse-code Symbol Assignments
Table 1.14 shows some examples of symbol assignments in the Morse code system. As shown in the table and stated earlier, the number of bits (i.e., length of the codes) assigned to encode letters vary from 1 to 4 bits, depending on the probability of their occurrence. Similarly, numbers, which occur less frequently than letters in languages, are assigned with a length of 5 bits each. In the same way, punctuation marks, which are the least-frequently occurring entities, are assigned with 6 bits each. It may be noted that use of Morse code has become very rare; yet its principles still remain very fresh in the sense that it was the first systematic study on coding languages based on probability theory.
Table 1.14 Morse codes assigned to letters, numbers, and punctuations
Letter/ number/ punctuation | Morse code in ● and ── | Morse code in 0s (●) and 1s (─) | Length of code in number of bits |
E A S Z 1 9 Full stop (.) Hyphen (-) | ● ● ── ●●● ── ●● ● ── ── ── ── ── ── ── ── ● ● ── ● ── ● ── ── ● ● ● ● ── | 0 01 000 1100 10000 00001 010101 100001 | 1 2 3 4 5 5 6 6 |