Question

How many bits per second must a keyboard transmit to keep up with a typist typing forty words per minute? (Assume each character is encoded in ASCII and each word consists of six characters.)

Short answer

The keyboard must transmit 28 bits per second.

Step-by-step solution

Calculate the Total Number of Characters Per Minute

First, determine how many characters the typist types in a minute. Starting with forty words per minute and assuming each word has six characters, calculate the total: \[40 \text{ words/minute} \times 6 \text{ characters/word} = 240 \text{ characters/minute}\]

Determine the Bits Required for Encoding

Since each character is encoded using the ASCII standard, which uses 7 bits per character, calculate the total bits needed per minute:\[240 \text{ characters/minute} \times 7 \text{ bits/character} = 1680 \text{ bits/minute}\]

Convert Character Transmission to Bits Per Second

To determine the number of bits transmitted per second, convert the previous result from bits per minute to bits per second:\[\frac{1680 \text{ bits/minute}}{60 \text{ seconds/minute}} = 28 \text{ bits/second}\]

Conclusion

Finally, the keyboard must transmit 28 bits per second to keep up with a typist typing forty words per minute.

Key concepts

Bits per Second

A bit is the most basic unit of data in computing and digital communications. It's a binary digit, meaning it can either be a 0 or a 1. When we talk about "bits per second" (bps), we're discussing the speed or rate at which bits are transmitted from one device to another.
In the context of a keyboard, the bits per second measure how fast data needs to be sent to match a user's typing speed. If a typist is typing quickly, more bits need to be sent each second. Calculating this involves understanding how many characters are being typed, how each character is encoded, and then converting those requirements into bits per second.
To find out how many bits a typist would need per second, one must determine the total number of bits sent in one minute and then divide by 60, because there are 60 seconds in a minute. This way, we can figure out the transmission speed in bits per second.

Keyboard Data Transmission

When you press a key on a keyboard, a signal is sent to the computer. This is what we call keyboard data transmission. This signal contains information about which key was pressed and this data is encoded into bits.
The keyboard takes the pressed key and converts it into a binary form, typically using a standard like ASCII (American Standard Code for Information Interchange). The keyboard then sends these bits to the computer, where they get translated back into characters by the operating system and appear on your screen.

• The process ensures that whatever key you press gets accurately displayed as the corresponding character.
• In digital systems, quick and reliable transmission of data is crucial for smooth interactions with computers.

The rate at which data is sent from the keyboard to the computer is pivotal in ensuring there are no delays, especially for fast typists.

Text Encoding

Text encoding is the process of converting characters into a specific binary format that computers can understand. ASCII is one of the most widely used encoding schemes.
ASCII uses 7 bits to represent each character. This includes letters (both uppercase and lowercase), digits, punctuation marks, and control characters. With this 7-bit scheme, ASCII can represent 128 different symbols.
The encoding process involves:

• Taking each typed character and finding its corresponding ASCII binary value.
• Transmitting this binary value so it can be processed and displayed by receiving devices.

Text encoding is essential for ensuring that different devices can exchange data correctly and consistently. It provides a standardized way to represent text so that computers worldwide "speak the same language" when it comes to processing and displaying text.

Typing Speed Calculation

Typing speed is usually measured in words per minute (WPM). This metric helps determine how fast a typist can enter information using a keyboard.
To calculate typing speed, you usually count the number of words typed in one minute. However, for precise data transfer calculations, each word is often assumed to have a standard number of characters - usually five or six, including spaces.
For example, if a typist types 40 words per minute and each word has about six characters, they are typing 240 characters per minute. This means, when considering ASCII encoding where each character requires 7 bits, the keyboard must handle 1680 bits per minute.

• Converting this rate into bits per second involves dividing the total bits per minute by 60.
• This conversion gives a useful measure in bits per second, essential for ensuring the keyboard keeps up with the user's typing speed without delay.

Understanding and calculating typing speed is crucial for optimizing data transmission, especially in scenarios involving rapid data entry.