1.What
is PAM?
PAM is the pulse modulation. In PAM
the amplitude of a carrier consisting of a periodic train of rectangular pulse
is varied in proportion to sample values of a message signal.
2.What
is PCM?
PCM is a process used to convert
analog signal to digital data. In PCM ,the analog signal is first sampled then
quantized then each sample is replaced with n bits binary data.
3.What
do you mean by nonlinear encoding in PCM system?
Nonlinear encoding is a technique
used to increase the performance of PCM system. In nonlinear encoding the
quantization levels are not equaled spaced. That is greater number of
quantization levels for signals of low amplitude and smaller number of
quantization levels for signals of high amplitude.
4.What
is called processing gain?
Processing gain is defined as the
ratio of the bandwidth of spread message signal to the bandwidth of unspreaded
data signal.
5.What
is meant by PCM?
PCM is a method of
signal coding in which the message signal is sampled, the amplitude of each
sample is rounded off to the nearest one of a finite set of discrete levels and
encoded so that both time and amplitude are represent in discrete form.
6.Define
quantization error.
It is the difference between the
output and input values of quantizer.
7.Define
quantization process.
The conversion of analog sample of
the signal into digital form is called quantization process.
8.Define
PPM.
The position of a constant width
pulse with in a time slot is varied according to the amplitude of the sample of
the analog signal.
9.Define
PWM.
The width of a constant amplitude
pulse is varied proportional to the amplitude of the analog signal at the time
the signal is sampled.
10.State
the advantage of angle modulation over amplitude modulation?
-Noise impurity
-Noise performance
-Signal to noise improvement
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