Delay processing apparatus, signal amplification apparatus, opto-electric conversion apparatus, analog-digital conversion apparatus, receiving apparatus, and receiving method

A signal amplification apparatus that is used with an analog-digital converter that converts, into digital signals, an in-phase signal and a quadrature signal that are obtained by demodulating multi-level phase modulated light, and a processor that carries out digital signal processing on the digital signals from the analog-digital converter to recover data, the signal amplification apparatus comprising:

• an amplification section that carries out amplification processing independently on the in-phase signal and the quadrature signal in analog electric signals;
• a delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal at the previous stage or the subsequent stage of the amplification section;
• and
• a delay control section that provides a feedback control on the delay amount provided by the delay device based on a quality of the signals when the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided the delay device, are converted into digital signals by the analog-digital converter, and the digital signal processing is carried out at the processor.

An opto-electric conversion apparatus that is used with an analog-digital converter that converts, into digital signals, an in-phase signal and a quadrature signal that are obtained by demodulating multi-level phase modulated light, and a processor that carries out digital signal processing on the digital signals from the analog-digital converter to recover data, the opto-electric conversion apparatus comprising:

• an opto-electric conversion section that converts the in-phase signal and the quadrature signal into respective electric signals through opto-electric conversion processing;
• a delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal at the previous stage or the subsequent stage of the opto-electric conversion processing;
• and
• a delay control section that provides a feedback control on the delay amount provided by the delay device based on a quality of the signals when the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided at the delay device, are converted into digital signals by the analog-digital converter, and the digital signal processing is carried out at the processor.

An analog-digital conversion apparatus that is used with a processor carrying out digital signal processing on digital signals from the analog-digital conversion apparatus to recover data, the analog-digital conversion apparatus comprising:

• an analog-digital conversion section that converts the in-phase signal and the quadrature signal into respective digital electric signals through analog-digital conversion processing;
• a delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal of the analog electric signals at the previous stage or the subsequent stage of the analog-digital conversion processing;
• and
• a delay control section that provides a feedback control on the delay amount provided by the delay device based on a quality of the signals when the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided at the delay device, is converted into the digital signals by the analog-digital conversion section, and the digital signal processing is carried out at the processor.

A receiving apparatus, comprising:

• a front-end section that receives a multi-level phase modulated optical signal and outputs an in-phase signal and a quadrature signal of an analog electric signal;
• a delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal;
• a plurality of analog-digital conversion sections that input the in-phase signal and the quadrature signal, the at least one of which is provided with the delay amount by the delay device;
• a digital signal processing section that carries out digital signal processing on the output from the analog-digital conversion section;
• and
• a delay control section that provides a feedback control on the delay amount at the delay device based on a result of the digital signal processing at the digital signal processing section.

A receiving apparatus, comprising:

• a receiver unit that receives a multi-level phase modulated light and outputs an in-phase signal and a quadrature signal as optical signals;
• an opto-electric conversion section that converts the in-phase signal and the quadrature signal of the optical signals output from the receiver unit into respective analog electric signals through opto-electric conversion processing;
• an amplification section that carries out amplification processing on the in-phase signal and the quadrature signal of the analog electric signals from the opto-electric conversion section;
• a delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal from the reception section;
• a temperature monitor that monitors temperatures at the opto-electric conversion section and the amplification section;
• and
• a delay control section that stores the temperatures at the opto-electric conversion section and the amplification section, and information on the delay amount to be set to at least one of the in-phase signal and the quadrature signal at the delay device in accordance with a gain at the amplification section, retrieves, from the store, the information on the delay amount corresponding to a monitor result from the temperature monitor and the gain at the amplification section, and controls the delay device in accordance with the retrieved delay amount.

A receiving method, comprising:

• receiving a multi-level phase modulated light and outputs an in-phase signal and a quadrature signal;
• providing a delay amount to at least one of the in-phase signal and the quadrature signal;
• converting the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided, into digital signals, and carrying out signal processing, and
• providing a feedback control on the provided delay amount based on a result of the signal processing.

A signal amplification apparatus, comprising:

• an amplification section that carries out amplification processing on an in-phase signal and a quadrature signal of an analog electric signal originating from multi-level phase modulated light;
• a delay section that provides a variable time delay to at least one of the in-phase signal and the quadrature signal at the previous stage or the subsequent stage of the amplification processing;
• and
• a delay control section that provides a feedback control on a delay amount at the delay section based on a result of a conversion of the in-phase signal and the quadrature signal including the signal to which the delay is provided at the delay section into digital signals and signal processing thereon.

An opto-electric conversion apparatus, comprising:

• an opto-electric conversion section that converts an in-phase signal and a quadrature signal of optical signals originating from multi-level phase modulated light to respective analog electric signals through opto-electric conversion processing;
• and
• a delay section that provides a variable time delay to at least one of the in-phase signal and the quadrature signal at the previous stage or the subsequent stage of the opto-electric conversion processing;
• and
• a delay control section that provides a feedback control on a delay amount at the delay section based on a result of a conversion of the in-phase signal and the quadrature signal including the signal to which the delay is provided at the delay section into digital signals and signal processing thereon.