| Quantized signal differs from the actual
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| | At the receiver, pulse code modulation is
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| signal. It leads to introduction of same
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| | translated back into corresponding pulse
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| distortion called quantizing noise. We
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| | amplitude modulated pulses which are then
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| use word noise here since the error so
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| | demodulated using conventional methods.
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| introduced is random in nature. Random
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| | At the output of an idealized pulse code
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| nature is resulted because the difference
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| | modulation receiver we get the quantized
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| between the quantized level or digit and
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| | wave. The binary numbers are sent back to
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| actual signal at that instant of time is
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| | front to indicate each sample. Number
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| completely unpredictable that is random.
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| | five is sent as 1010 instead of 0101.
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| Evident are there that the maximum
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| | Similarly number eleven is sent as 1101
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| quantization error equals half the
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| | instead of 1011. In the receiver an
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| sampling unit. All error equals one by
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| | integrated resistance capacitance circuit
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| thirty two of the total signal range. We
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| | is used for conversion. The pulses are
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| should not assume that signal to
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| | applied to the integrating circuit and
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| quantizing noise ratio of this system is
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| | are then sampled and discharged
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| thirty two is to one because neither the
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| | immediately after the arrival of the
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| signal nor the instantaneous quantizing
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| | pulse. The time constant of resistance
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| error has always its maximum value.
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| | capacitance circuit is so chosen that the
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| By using statistical methods we can
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| | charge due to one pulse decays to exactly
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| calculate quantizing noise for a given
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| | to one half of its value by the time the
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| number of quantizing levels. Quantizing
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| | next pulse arrives. The each last pulse
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| noise reduces as the number of standard
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| | contributes to the total output in the
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| levels increases but increase in the
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| | preceding one micro second duration the
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| number of quantizing levels necessitates
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| | second last pulse will have decayed to
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| large number of bits to send them and
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| | half of its original value. Thus its
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| requires large bandwidth. In practical
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| | contribution to the output is half volt.
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| system for speech transmission hundred
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| | Similarly contribution of each third last
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| and twenty eight quantizing levels are
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| | pulse will be one by fourth volts and
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| sufficient. The signal is first sampled
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| | that of each fourth last will be one by
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| and converted to pulse amplitude
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| | eighth volts and so on. Output pulses are
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| modulated signal. Then the pulse
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| | obtainable only if a pulse is received in
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| amplitude modulated signal is quantized
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| | indicated positions.
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| and encoded and supervisory signals are
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| | Tymon Hytem has worked in the electronics
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| added. The signal is then sent directly
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| | feild for the past 15 years. He enjoys
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| through cable or is modulated and
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| | helping people decide on electronic
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| transmitted. The pulse code modulation is
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| | gadgets from telephones to XM Radio and
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| highly immune to noise hence amplitude
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| | choosing the perfect XM Satellite Radio
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| modulation may be used resulting in pulse
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| | system for their needs.
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| code modulation and amplitude modulation.
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