In this note, we are going to learn about the Block Diagram of QPSK Modulation and Demodulation or Transmitter and Receiver. Welcome to Poly Notes Hub, a leading destination for engineering notes.

Author Name: Arun Paul.

Block Diagram of QPSK Modulation and Demodulation

QPSK is a four phase modulation technique. Input of the QPSK is a two-bit splittee. Two binary bits can form four different combination of 1 and 0 states. Each combination generates a separate vector at the output. For example, if both bits are low, the output of the balanced modulator will be 180° out of phase with their respective inputs.

Advantages of QPSK or Quadrature Phase Shift Keying

• It requires less amount of bandwidth.
• Because of less bandwidth the transmission rate is higher in QPSK.

Block Diagram of QPSK Transmitter

This is the block diagram of QPSK Modulation or Transmitter –

In a QPSK transmitter, the input binary sequence is first converted to a bipolar signal. It represents binary ‘1’ by + 1V and binary’ 0 by 1V. The demultiplexer divided the signal into two separate bit streams of even and odd-numbered bits.

Block Diagram of QPSK Receiver

This is the block diagram of QPSK Demodulation or Receiver –

The received QPSK signal is applied to both Multipiliers. The integrator integrates the product signal over a two-bit interval. The output integrator is sampled, and both are fed into the input of the multiplexer. It means that both odd and even sequences are combined by the multiplexer.