Abstracto

A Direct Injection-Locked QPSK Modulator Based on Ring VCO

K.Gopi, T.Kowsalya

QPSK or Quadrature Phase-Shift Keying is a higher order modulation scheme used in digital modulation. A direct injection locked QPSK modulator uses VCO for minimize the area of the conventional modulator. In this project injection locking scheme is used since injection locking has an advantage inphase-noise reduction ofoscillators withavery simplecircuittopology. By using proposed simple modulator many blocks removed so that total area is reduced. The proposed quadraturephase-shiftkeying (QPSK) was fabricated in 90 nm CMOS, occupies less area.