Analogue and Digital signals Flashcards Preview

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Flashcards in Analogue and Digital signals Deck (14):


Can take any value in certain range /Width and varies continuously .



It can take 1/0 which can be known as on and off


Which one is weaker ?

Analogue weaken as they travel so they might need to amplified along their routes .They pick interference or noise from electrical disturbance.


What happens when you amplify analogue ?

The noise is amplified to the signal looses quality .However, the noise is easier to remove with digitals signals so therefore signals can remain high quality . But for analogue the signal looses strength which may cause poor signal .


Digitising information

Send more data faster and with high quality .

More reliable and interference free .

Light with be maintained with optical fibres .


How do you convert Analogue to Digital converter ?

Connect a sensor transducer to give an analogue a signal into the ADC input

Select sampling rate and sensitivity

Send the digital output signal to a display or a data storage device .


Digital accuracy

Sampling rate :Is the number of times per second that the quality is measured .

Sampling sensitivity :
Is the smallest increments in the quality measured and recorded

What do they do ?
They set a limit on the accuracy of digitised information .


Why is digital much better in sending information ?

Can send information over long distances by cutting off noise interference not a problem

Transmit several signals at the same time using just one cable

Switching over from analogue to digital signals .

Can be stored and processed by computer

Digital signals :

Time can be delayed due to signal processing

Data accuracy limited by sampling setting


Step by step Analogue to digital conversion

1.Select a transducer a device produces an analogue to electrical voltage signal proportional to the quantity you want to measure .

2.Connect the output of the transducer to the input of an A to D converter using a screened cable .To avoid picking up electrical interference screening must be earthed.

3. Set up the A to D converter to sample the analogue signal. This is equivalent to taking measurements to plot results out on a voltage time graph.

4. Select an appropriate sampling rate which is your sensitivity on the time .

5. Select an appropriate sensivity for the conversion of the voltage signal into a number .Smaller difference is one unit .

6. Connect A to D converter output to a switch transmitter to send digital information either electronically wirelessly by Bluetooth etc. by optical signals


Example of analogue

The electrical signals made by a microphone which mimics the shape and intensity of the sound waves they are detecting .

The position of the point on a pressure dial gauge .


Optical fibres

Optical fibres can convey more information than just one pixel .Digital signals are numbers in binary code which is a series of zeros and ones .



Very high frequencies can be used as huge amounts of digital data can be transmitted in a short time.

A whole television picture can be digiataisd as a string of numbers that represent the brightness and colours of every pixel in it which can arrive home travelling a single digital fibre cable .


Binary code

uses base 2 rather than 10 because so it represent any number as a series of ones and zeroes .


Why do voices sound odd on the phone ?

This is because there is limited frequency is reproduced by the digital sampling telephone system saves data space and looses quality .