US-12627323-B2 - Signal generation apparatus, signal generation method, and computer program

US12627323B2US 12627323 B2US12627323 B2US 12627323B2US-12627323-B2

Abstract

A signal generation device that includes a digital signal processing unit, a plurality of digital-analog conversion units that respectively converts a plurality of digital signals output from the digital signal processing unit into analog signals, and an analog multiplexer that interleaves the analog signals respectively output from the plurality of digital-analog conversion units to generate a broadband signal, in which the digital signal processing unit includes a serial-parallel conversion unit that divides an input signal into a number according to a ratio between a sampling frequency of the plurality of digital-analog conversion units and a clock frequency of the analog multiplexer in a time domain to generate a plurality of divided signals, and a plurality of convolution arithmetic operation units that receives the plurality of divided signals generated by the serial-parallel conversion unit as inputs and generates a plurality of digital signals corresponding to the respective digital-analog conversion units.

Inventors

Masanori Nakamura
Hiroshi Yamazaki
Munehiko Nagatani
Fukutaro Hamaoka
Takayuki Kobayashi
Yutaka Miyamoto

Assignees

NTT, INC.

Dates

Publication Date: 20260512
Application Date: 20220304

Claims (6)

1 . A signal generation device comprising: a digital signal processor; a plurality of digital-analog converters configured to respectively convert a plurality of digital signals output from the digital signal processor into analog signals; and an analog multiplexer configured to interleave the analog signals respectively output from the plurality of digital-analog converters to generate a broadband signal, wherein the digital signal processor includes a serial-parallel converter configured to divide an input signal into a number according to a ratio between a sampling frequency of the plurality of digital-analog converters and a clock frequency of the analog multiplexer in a time domain to generate a plurality of divided signals, a plurality of convolution arithmetic operators configured to perform a convolution arithmetic operation for the plurality of divided signals generated by the serial-parallel converter, and a plurality of adders configured to add the plurality of divided signals for which the convolution arithmetic operation has been performed by the plurality of convolution arithmetic operators to generate a plurality of digital signals corresponding to the respective digital-analog converters.
2 . The signal generation device according to claim 1 , wherein, in a case where the clock frequency for driving the analog multiplexer is ½ of a sampling frequency of the broadband signal, the plurality of convolution arithmetic operators is four convolution arithmetic operators, the plurality of adders is two adders, the serial-parallel converter divides the input signal into two pieces in the time domain to generate two divided signals, the four convolution arithmetic operators multiply one divided signal by a response function for every two convolution arithmetic operators included in the four convolution arithmetic operators, and the two adders add the plurality of divided signals for which the convolution arithmetic operation has been performed by the four convolution arithmetic operators to generate the plurality of digital signals corresponding to the respective digital-analog converters.
3 . The signal generation device according to claim 1 , wherein, in a case where the clock frequency for driving the analog multiplexer is ¼ of a sampling frequency of the broadband signal, the plurality of convolution arithmetic operators is sixteen convolution arithmetic operators, the plurality of adders is four adders, two parallel-serial converters configured to perform parallel-serial conversion for the plurality of divides output from the four adders are further included, the serial-parallel converter divides the input signal into four pieces in the time domain to generate four divided signals, the sixteen convolution arithmetic operators multiply one divided signal by a response function for every a four convolution arithmetic operators included in the four convolution arithmetic operators, the four adders add the plurality of divided signals for which the convolution arithmetic operation has been performed by the sixteen convolution arithmetic operators to generate the plurality of digital signals corresponding to the respective digital-analog converters, and each of the two parallel-serial converters performs parallel-serial conversion for the plurality of digital signals output from two adders included the four adders that are different from each other.
4 . The signal generation device according to claim 1 , wherein, in a case where the clock frequency for driving the analog multiplexer is ⅙ of a sampling frequency of the broadband signal, the plurality of convolution arithmetic operators is thirty-six convolution arithmetic operators, the plurality of adders is six adders, two parallel-serial converters that perform parallel-serial conversion for the plurality of digital signals output from the six adders are further included, the serial-parallel converter divides the input signal into six pieces in the time domain to generate six divided signals, the thirty-six convolution arithmetic operators multiply one divided signal by a response function for every six convolution arithmetic operators included in the thirty-six convolution arithmetic operators, the six adders add the plurality of divided signals for which the convolution arithmetic operation has been performed by the thirty-six convolution arithmetic operators to generate the plurality of digital signals corresponding to the respective digital-analog converters, and each of the two parallel-serial converters performs parallel-serial conversion for the plurality of digital signals output from three adders included in the six adders that are different from one another.
5 . A signal generation method comprising: by a digital signal processor, dividing an input signal into a number according to a ratio between a sampling frequency of a plurality of digital-analog converters and a clock frequency of an analog multiplexer in a time domain to generate a plurality of divided signals; by the digital signal processor, performing a convolution arithmetic operation for the plurality of divided signals; by the digital signal processor, adding the plurality of divided signals for which the convolution arithmetic operation has been performed to generate a plurality of digital signals corresponding to the respective digital-analog converters; by the plurality of digital-analog converters, respectively converting the plurality of digital signals output from the digital signal processor into analog signals; and by the analog multiplexer, interleaving the analog signals respectively output from the plurality of digital-analog converters to generate a broadband signal.
6 . A non-transitory storage medium that stores a program for making a computer perform processes, the processes comprising: dividing an input signal into a number according to a ratio between a sampling frequency of a plurality of digital-analog converters and a clock frequency of an analog multiplexer in a time domain to generate a plurality of divided signals; performing a convolution arithmetic operation for the plurality of divided signals; adding the plurality of divided signals for which the convolution arithmetic operation has been performed to generate a plurality of digital signals corresponding to the respective digital-analog converters; converting the plurality of digital signals into analog signals; and interleaving the analog signals to generate a broadband signal.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a 371 U.S. National Phase of International Application No. PCT/JP2022/009445, filed on Mar. 4, 2022. The entire disclosure of the above application is incorporated herein by reference. TECHNICAL FIELD The present invention relates to a signal generation device, a signal generation method, and a computer program. BACKGROUND ART A high-quality high-speed signal generation technology for increasing the capacity of optical transmission has attracted attention. As such a technology, for example, a signal generation device has been proposed, which divides an input signal to be a target into a low frequency and a high frequency and pre-equalizes a divided signal and a complex conjugate signal of the divided signal by multiple input multiple output (MIMO) processing (see, for example, Patent Literature 1). FIG. 6 is a diagram illustrating a configuration example of a conventional signal generation device 100. The signal generation device 100 includes a band division unit 611, a spectrum folding unit 612, a filter 613, a plurality of sub digital analog converters (DACs) 121 and 122, and an analog multiplexer 131. The band division unit 611 divides an input signal 101 into a low frequency and a high frequency. The spectrum folding unit 612 generates a complex conjugate signal of a divided signal. The filter 613 receives each divided signal and each complex conjugate signal as inputs, and generates a plurality of composite signals to be transmitted to the plurality of SubDACs 121 and 122. The SubDACs 121 and 122 convert the plurality of composite signals output from the filter 613 into a plurality of analog signals. The analog multiplexer 131 receives the plurality of analog signals as inputs and generates a high-speed signal. CITATION LIST Patent Literature Patent Literature 1: WO 2020/054173 A SUMMARY OF INVENTION Technical Problem However, a signal generation method by a conventional signal generation device has a problem of deterioration in signal quality due to an influence of frequency ripples and an increase in peak-to-average power ratio (PAPR) because steep cutout in a frequency domain occurs when dividing an input signal. In view of the above circumstances, an object of the present invention is to provide a technique capable of generating a broadband signal with high signal quality. Solution to Problem One aspect of the present invention is a signal generation device including: a digital signal processing unit; a plurality of digital-analog conversion units that respectively converts a plurality of digital signals output from the digital signal processing unit into analog signals; and an analog multiplexer that interleaves the analog signals respectively output from the plurality of digital-analog conversion units to generate a broadband signal, in which the digital signal processing unit includes a serial-parallel conversion unit that divides an input signal into a number according to a ratio between a sampling frequency of the plurality of digital-analog conversion units and a clock frequency of the analog multiplexer in a time domain to generate a plurality of divided signals, a plurality of convolution arithmetic operation units that performs a convolution arithmetic operation for the plurality of divided signals generated by the serial-parallel conversion unit, and a plurality of addition units that adds the plurality of divided signals for which the convolution arithmetic operation has been performed by the plurality of convolution arithmetic operation units to generate a plurality of digital signals corresponding to the respective digital-analog conversion units. One aspect of the present invention is a signal generation method including: by a digital signal processing unit, dividing an input signal into a number according to a ratio between a sampling frequency of a plurality of digital-analog conversion units and a clock frequency of an analog multiplexer in a time domain to generate a plurality of divided signals; by the digital signal processing unit, performing a convolution arithmetic operation for the plurality of divided signals; by the digital signal processing unit, adding the plurality of divided signals for which the convolution arithmetic operation has been performed to generate a plurality of digital signals corresponding to the respective digital-analog conversion units; by the plurality of digital-analog conversion units, respectively converting the plurality of digital signals output from the digital signal processing unit into analog signals; and by the analog multiplexer, interleaving the analog signals respectively output from the plurality of digital-analog conversion units to generate a broadband signal. An aspect of the present invention is a computer program for causing a computer to function as the above-described signal generation device. Advantageous Effects of Invention According to the present invention, it is pos