Mixer having phase shift function and communications device including the same

A communications device, comprising:

• a modulator configured to generate a plurality of baseband signals;
• a local oscillation signal generator configured to generate a plurality of local oscillation signals;
• a multiplexer or a buffer configured to receive the plurality of the local oscillation signals and phase-shift the plurality of the local oscillation signals to generate a plurality of source terminal input signals wherein a phase difference between the plurality of the local oscillation signals and the plurality of the source terminal input signals is 90 degrees;
• a mixer configured to receive the plurality of the source terminal input signals and the plurality of baseband signals, further configured to phase-shift the plurality of the baseband signals by a value equal to or lower than 45 degrees.

A communications device, comprising:

• a modulator configured to generate a plurality of first baseband signals by modulating a transmit bitstream;
• a local oscillation signal generator configured to generate a plurality of first local oscillation signals;
• a multiplexer configured to receive the plurality of first local oscillation signals and multiplex the plurality of first local oscillation signals to generate a plurality of second local oscillation signals, wherein the plurality of second local oscillation signals are phase-shifted with respect to the plurality of first local oscillation signals;
• a mixer configured to generate a radio frequency transmit signal by up-conversion of the plurality of first baseband signals using the plurality of second local oscillation signals,
• wherein the mixer is configured to generate a plurality of second baseband signals phase-shifted by a second phase value with respect to the plurality of first baseband signals by combining the plurality of first baseband signals, and to perform a mixing operation with respect to the plurality of second baseband signals and the plurality of second local oscillation signals.