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Digital Codes
12 questions By Tony R. Kuphaldt
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Question 10 of 12
Convert the following decimal numbers into BCD form:
- 73910
- 2510
- 9224110
Convert the following BCD numbers into decimal form:
- 1000 1001
- 0100 0111 0110
- 0011 1000 0101 0001
Reveal answer- 73910 = 0111 0011 1001
- 2510 = 0010 0101
- 9224110 = 1001 0010 0010 0100 0001
- 1000 1001 = 8910
- 0100 0111 0110 = 47610
- 0011 1000 0101 0001 = 385110
Notes:Nothing but straightforward conversions here!
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Question 11 of 12
Explain how the Morse Code resembles ASCII in structure and purpose.
Reveal answerMorse Code is digital, being composed of only two types of characters, just like ASCII. Also, its purpose is to convey alphanumeric information, just like ASCII.
Notes:An interesting point to bring up to students about Morse Code is that it is self-compressing. Note how different Morse characters possess different “bit” lengths, whereas ASCII characters are all 7 bits each (or 8 bits for Extended ASCII). This makes Morse a more efficient code than ASCII, from the perspective of bit economy!
Ask your students what ramifications this “self-compressing” aspect of Morse Code would have if we were to choose it over ASCII for sending alphanumeric characters over digital communications lines, or store alphanumeric characters in some form of digital memory media.
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Question 12 of 12
Standard ASCII codes are seven bits in length, but communications equipment usually sends data in eight-bit (byte) groups. The extra bit is often used as a parity bit. What is the purpose of a “parity bit,” and how is it used?
Reveal answer“Parity bits” are used as a primitive form of error detection. Communications equipment making use of parity for error detection may either be configured for “even parity” or for “odd parity”. I’ll let you research and explain how parity bits are used in the transmission of ASCII data.
Notes:The concept of parity is not very complex. It should be well within the reach of students to research on their own and report their findings to the class as a whole.
