Data Transmission and Networks Bit rate Baud rate

Data Transmission and Networks Bit rate / Baud rate

Learning Objectives Explain bit rate/baud rate.

Bit / Baud Rate The speed at which a given amount of data can be transmitted. n The number of bits that can be sent in one second is known as the BIT RATE. The units used to measure the bit rate are BAUD. n 1 baud = 1 bit per second.

Transmitting Pictures / Graphics Pictures take up a lot of memory because each pixel must be defined. High resolution (quality) means more pixels and more colours. There is a limit to the amount of information that can be transmitted in a given time down the phone line. n Choice 1: Have as much detail as possible and accept that it will take a long time to transmit it. n Choice 2: Limit the resolution (quality) of the picture, meaning that there is less information to send so that the message will be sent more quickly.

Transmitting Text files contain a relatively small amount of data (compared to pictures / graphics / video) because each character only takes one byte. n Text files are not time sensitive. They can still be read even if the bit / baud rate is slow and they get sent pretty quickly anyway due to their relatively small size.

Transmitting Video Large amount of data which must be transmitted in a standard time frame. n A video cannot be run (watched) without a high bit / baud rate.

Importance of Bit / Baud Rate More important the more data there is. n Due to the increasing time required for transfer. Different volumes per second mean that different transfer rates are appropriate. n Videos demand a high bit / baud rate Contain a large amount of data. Must be transmitted in a standard time frame. n Pictures take a long time without a high bit / baud rate. Large amount of data because each pixel must be defined. n Text doesn’t need a high bit / baud rate. Small amount of data. Not time sensitive.

Plenary Can you explain bit rate/baud rate? n The speed at which a given amount of data can be transmitted.

Plenary Explain the importance of bit rates to communication.

Importance of Bit / Baud Rate More important the more data there is. n Due to the increasing time required for transfer. Different volumes per second mean that different transfer rates are appropriate. n Videos demand a high bit / baud rate Contain a large amount of data. Must be transmitted in a standard time frame. n Pictures take a long time without a high bit / baud rate. Large amount of data because each pixel must be defined. n Text doesn’t need a high bit / baud rate. Small amount of data. Not time sensitive.