Signal recovery circuit, optical module, and signal recovery method

An optical module comprising:

• a voltage controlled oscillator configured to generate a clock signal;
• a phase frequency comparison circuit configured to:
• compare phases of the clock signal and an received input signal, and
• compare frequencies of the clock signal and the received input signal;
• a voltage adjustment circuit configured to adjust the phase of the clock signal by adjusting control voltage of the voltage controlled oscillator based on an output of the phase frequency comparison circuit;
• a control circuit configured to:
• acquire an amplitude of the input signal,
• detect continuation of the same sign in the input signal based on the acquired amplitude,
• stop an adjustment of the phase of the clock signal generated by the voltage controlled oscillator when the continuation of the same sign is detected, and
• execute adjustment of the phase of the clock signal generated by the voltage controlled oscillator when the continuation of the same sign is stopped;
• an identification circuit configured to:
• generate an identification signal by identifying the input signal based on the clock signal generated by the voltage controlled oscillator, and
• output the generated identification signal;
• a drive circuit configured to output a control signal based on an input identification information by inputting the identification signal;
• a light emitting circuit configured to output an optical signal based on an input control signal by inputting the control signal;
• a light receiving circuit configured to:
• convert the input optical signal into current, and
• output converted current;
• and
• a transimpedance amplifier configured to:
• convert the current into voltage, and
• output amplified voltage to each of the phase frequency comparison circuit, the control circuit, and the identification circuit.

A signal recovery method for a signal recovery circuit including a voltage controlled oscillator configured to generate a clock signal, a phase frequency comparison circuit, a voltage adjustment circuit, and a control circuit, the method comprising:

• comparing, by the phase frequency comparison circuit, phases of the clock signal and a received input signal;
• comparing, by the phase frequency comparison circuit, frequencies of the clock signal and the received input signal;
• adjusting, by the voltage adjustment circuit, the phase of the clock signal by adjusting control voltage of the voltage controlled oscillator based on an output of the phase frequency comparison circuit;
• acquiring, by the control circuit, an amplitude of the input signal;
• detecting, by the control circuit, continuation of the same sign in the input signal based on the acquired amplitude;
• stopping, by the control circuit, an adjustment of the phase of the clock signal generated by the voltage controlled oscillator when the continuation of the same sign is detected;
• and
• executing, by the control circuit, adjustment of the phase of the clock signal generated by the voltage controlled oscillator when the continuation of the same sign is stopped.