Here are the definitions of the terms related to data transmission and communication systems:
1. Bandwidth:
- Definition: Bandwidth refers to the range of frequencies that a communication channel can transmit. It is measured in hertz (Hz) and indicates the difference between the highest and lowest frequencies that can pass through the channel. Higher bandwidth allows more data to be transmitted over a period of time.
- Example: If a channel can transmit frequencies between 20 Hz and 2000 Hz, the bandwidth is 1980 Hz.
2. Bit Rate:
- Definition: Bit rate is the number of bits transmitted per second (bps) over a communication channel. It measures the amount of data transmitted in a given time frame.
- Example: A bit rate of 1000 bps means 1000 bits are sent every second.
3. Bit Interval:
- Definition: Bit interval is the time taken to transmit one single bit of data. It is the reciprocal of the bit rate. If the bit rate is high, the bit interval is short, meaning more bits are transmitted in less time.
- Example: If the bit rate is 1000 bps, the bit interval is 1/1000 seconds, or 1 millisecond.
4. Baud Rate:
- Definition: Baud rate refers to the number of signal units (symbols or changes) transmitted per second. Each signal change can represent one or more bits depending on the modulation technique used. Baud rate and bit rate are the same only when one signal change represents exactly one bit.
- Example: If a signal transmits 2 bits per symbol, and the baud rate is 1000 symbols per second, the bit rate is 2000 bps.
5. Transmission Impairment:
Transmission impairments occur when the signal is degraded as it travels through the communication medium. The most common types of impairments are:
- Attenuation:
- Definition: Attenuation is the gradual loss of signal strength as it travels through a medium (like a copper wire or fiber optic cable). It typically increases with distance, and the signal may need to be amplified to maintain clarity.
- Example: When a signal travels a long distance through a cable, its strength diminishes and might require a repeater or amplifier to restore it.
- Distortion:
- Definition: Distortion refers to the change in the shape of the signal, often due to different frequencies traveling at different speeds in the medium. This can cause the signal to be received incorrectly or out of sync.
- Example: A signal transmitted over a telephone line may suffer distortion due to the characteristics of the wire, causing the received signal to look different from the original.
- Noise:
- Definition: Noise is any unwanted signal that interferes with the original transmitted signal. It can come from various sources, such as electrical interference, crosstalk, or background environmental signals.
- Example: In a communication system, noise can cause errors in data transmission, requiring techniques like error correction to ensure data integrity.
These concepts are fundamental to understanding how data is transmitted over networks and how various factors can affect communication quality.
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