Principle
Rather than quantizing the absolute value of the input analog waveform, delta modulation quantizes the difference between the current and the previous step, as shown in the block diagram in Fig. 1.
The modulator is made by a quantizer which converts the difference between the input signal and the average of the previous steps. In its simplest form, the quantizer can be realized with a comparator referenced to 0 (two levels quantizer), whose output is 1 or 0 if the input signal is positive or negative. It is also a bit-quantizer as it quantizes only a bit at a time. The demodulator is simply an integrator (like the one in the feedback loop) whose output rises or falls with each 1 or 0 received. The integrator itself constitutes a low-pass filter.
Read more about this topic: Delta Modulation
Famous quotes containing the word principle:
“The selfish spirit of commerce, which knows no country, and feels no passion or principle but that of gain.”
—Thomas Jefferson (1743–1826)
“It were as wise to cast a violet into a crucible that you might discover the formal principle of its colour and odour, as seek to transfuse from one language into another the creations of a poet. The plant must spring again from its seed, or it will bear no flower—and this is the burthen of the curse of Babel.”
—Percy Bysshe Shelley (1792–1822)
“To light one candle to God and another to the Devil is the principle of wisdom.”
—José Bergamín (1895–1983)