Voltage controlled oscillator, receiver, and communication device

A receiver comprising:

• a photodiode for converting optical signals into electric signals;
• a clock data recovery member for extracting data and synchronous signals from the electric signals;
• a voltage controlled oscillator for providing signals to operate the clock data recovery;
• a deserializer for converting serial data extracted by the clock data recovery member into parallel data;
• and
• a decoder for decoding the parallel data, wherein the voltage controlled oscillator includes:
• an amplifier;
• a surface acoustic wave element for forming a feedback circuit for the amplifier;
• a phase adjustment circuit including a filter and interposed in the feedback circuit;
• a phase shifter including a hybrid coupler to which an additional control part is attached for changing a phase value within an oscillation loop with control voltage supplied from an external source;
• an equal power divider for equally distributing output power within the oscillation loop and supplying the output power outside the oscillation loop;
• and
• a multi-layer board for mounting the amplifier, surface acoustic wave element, phase adjustment circuit, phase shifter, and equal power divider in at least two separate layers.

A communication device comprising:

• an access control part for controlling data access;
• an oscillator for generating synchronous clocks;
• a PLL control part for controlling frequencies based on outputs from the oscillator;
• an encoder for combining and encoding parallel data from the access control part and the synchronous clocks;
• a serializer for converting the parallel data combined with the synchronous clocks into serial data;
• a laser diode for converting the serial data into optical signals;
• a photodiode for converting the optical signals into electric signals;
• a clock data recovery for extracting the data and synchronous signals from the electric signals;
• a voltage controlled oscillator for providing signals to operate the clock data recovery;
• a deserializer for converting serial data extracted by the clock data recovery into parallel data;
• and
• a decoder for decoding and supplying the parallel data to the access control part, wherein the voltage controlled oscillator comprises:
• an amplifier;
• a surface acoustic wave element for forming a feedback circuit for the amplifier;
• a phase adjustment circuit including a filter and interposed in the feedback circuit;
• a phase shifter including a hybrid coupler to which an additional control part is attached for changing a phase value within an oscillation loop with control voltage supplied from an external source;
• an equal power divider for equally distributing output power within the oscillation loop and supplying the output power outside the oscillation loop;
• and
• a multi-layer board for mounting the amplifier, surface acoustic wave element, phase adjustment circuit, phase shifter, and equal power divider in at least two separate layers.