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Junior Varsity
How audio is transferred through wiring.
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<blockquote data-quote="Paul Johnson" data-source="post: 217579" data-attributes="member: 2643"><p>No, the captured sampled digital waveform is always positive. I'm OK with computers, but the maths element of sampling is usually actioned with an offset, so say a -.5 to +.5 voltage <em>swing </em>has to be converted to a 0 to 1V version to be sampled in the usual manner. This conversion is the aspect I am confused by because of the requirement to know the 'swing'. A small waveform or a big waveform would need to be altered in offset to move the central (old) 0V crossover to half of the maximum voltage swing, so in a 5V TTL type circuit, the crosspoint would be at 2.5V. I don't understand exactly how a conventional AC waveform can be made 100% so it can be sampled. This is required because each digital word in the sampling system needs to swing from digital 0 to digital max, at whatever bit rate you are sampling at. I'm happy with Nyquists work, but I have never understood how the conversion from AC to DC actually works. I completely understand the concept of the analogue waveform, but am stuck at the conversion to the digital levels individually recorded in the sequence. How do they get actually sampled at an accurate point in time, as a positive value. Or does the digital sampling split negative and positive halves and somehow amalgamate them in the sample result?</p></blockquote><p></p>
[QUOTE="Paul Johnson, post: 217579, member: 2643"] No, the captured sampled digital waveform is always positive. I'm OK with computers, but the maths element of sampling is usually actioned with an offset, so say a -.5 to +.5 voltage [I]swing [/I]has to be converted to a 0 to 1V version to be sampled in the usual manner. This conversion is the aspect I am confused by because of the requirement to know the 'swing'. A small waveform or a big waveform would need to be altered in offset to move the central (old) 0V crossover to half of the maximum voltage swing, so in a 5V TTL type circuit, the crosspoint would be at 2.5V. I don't understand exactly how a conventional AC waveform can be made 100% so it can be sampled. This is required because each digital word in the sampling system needs to swing from digital 0 to digital max, at whatever bit rate you are sampling at. I'm happy with Nyquists work, but I have never understood how the conversion from AC to DC actually works. I completely understand the concept of the analogue waveform, but am stuck at the conversion to the digital levels individually recorded in the sequence. How do they get actually sampled at an accurate point in time, as a positive value. Or does the digital sampling split negative and positive halves and somehow amalgamate them in the sample result? [/QUOTE]
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