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