Septemous, If you send digital data over wireless or network it will be delivered as data without timing and anything on computer side doesn't matter. What matters is timing (clock) recreated on the other side. When you transfer sequence 10101010 to D/A converter stability of timing (clock) becomes important. When edges don't come in uniform time spacing we call it jitter. This jitter is a form of modulation that creates additional analog signals. With complex signal there will be a lot of additional frequencies at very low level - basically a noise. This noise will be proportional to sound level and not detectable without signal. It is loss of clarity that affects everything from timbre to imaging. Cables can add to signal jitter by either allowing electrical noise to enter the cable (poor shielding) or by creating reflections inside of the cable. In either case transition edge becomes jagged. Since level is recognized at certain voltage (threshold) jagged edges will make jittery timing of A/D conversion. Noise is obvious but reflections need explanation. Fast transitions will create reflection (that will add back to signal) on any change in characteristic impedance of the connection (driver, connector, cable, connector, receiver). This characteristic impedance is pretty much square root of inductance over capacitance Zo=SQRT(L/C) and is defined by cable's geometry and dielectric.
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