but we know that sin2A = ½(1 - cos 2A)

then         E(t) = ½( 1 - cos 2wct)
                       = ½-½cos2wct

• at the output of the LPF:
  the high frequency signal is filtered out. Hence,

               E(t) = ½ Volts

Note: M-ary encoding : N =log2 M (no. of bits)

    2.2 Quarternary Phase Shift Keying (QPSK)

• Here the term quadrature (or 4-angle modulation) refers to the fact that the phase is shifted in 90o increments by manipulating both sine and cosine waveform.
• The theoretical limit is to provide 2 bits for every Hertz of frequency.
• Each symbol will carry one of 00, 01,10 or 11.
• Common form of modulation used in digital Tv transmission.

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