In DPSK technique, the technique used to encode bits is : 

The correct answer is Differential code.

Key Points

• The Differential Phase Shift Keying (DPSK) technique is a type of phase modulation technique used in digital communication systems.
  • In DPSK, the phase of the carrier signal is shifted relative to the phase of the previous signal element rather than to a fixed reference phase.
  • This technique is known for its simplicity and robustness against phase synchronization issues.
  • DPSK does not require a coherent reference signal at the receiver, making the receiver design simpler.
  • The encoding of bits in DPSK is done using differential coding, where each bit is encoded relative to the previous bit.

Additional Information

• In differential coding, a binary '1' may be represented by a phase change, while a binary '0' may be represented by no phase change.
• This method of encoding helps in overcoming the problem of phase ambiguity in the received signal.
• DPSK is widely used in various communication systems, including wireless and optical communication systems.
• Common applications of DPSK include Bluetooth technology and some forms of satellite communication.