To Convert Analogue to digital use an A2D converter |
█ How Does it work? |
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If you draw vertical line at any point along the input the value can be read as 4 it binary number from 0000 to 1111 or (0 - 15 decimal).
This value if sampled regularly can be sent through a digital network as a number in a packet or encoded onto a transport system ie a wire or RF. |
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It should be noted that this is not he only way to achieve the output but for now that will suffice. |
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█ How to get digital number on rf? |
Digital numbers can be transmitted in serial format like CW only with a few tweaks. Ignore the speed but as speed increases so does loss due to capacitance, DC baseline wander and also clock recovery. |
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DC wander is when the base line can not be defined because the 0ve value has changed. Imagine sending a regular square wave or more accurately 10101010 etc. First the clock recovery is easy as you see every bit (Rise in voltage at the leading edge of the 1). The 0 value is also seen every pulse so no problem but what happens if say a string of 1 are to be sent. (010111111101) The clock recovery fails because it is not sure when one pulse ends and another starts from one 1 to another. Also the line gets charged up so the next 0 is not at the 0 value but somewhere above so is it a 0 or a 1? So how to fix all this is a bit clever. |
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| First Clock Recovery |
when a square is sent the leading edge (rise or fall) triggers the start of the clock and the internal oscillator is forced to line up with it. Then the internal clock should line up every time with the leading edge. If no edge is detected then the oscillator free runs but no guarantee it is in time with the incoming train of pulses. This is ok for a couple of pulses but longer and the two clock values can drift apart. The internal clock is so arranged that it will sample the pulse in the middle of the pulse allowing time for the value to settle in the register and also allowing for a slightly longer or not vertical rise time. |
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A string of 1's would cause havoc if no measure was take to alleviate it. |
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