Data compression apparatus, data decompression apparatus, data compression system, control circuit, storage medium, data compression method, and data decompression method

A control circuit to control a data compression apparatus, the control circuit causing the data compression apparatus to perform:

• outputting sampling sequences corresponding to signals obtained by adding different delay times to different signals obtained by branching a target signal into a plurality of lines, and sampling the signals at a sampling rate-less than of a Nyquist rate;
• and
• converting the sampling sequences into compressed data and outputting the compressed data, and
• causing the data compression apparatus to perform:
• as converting the sampling sequences into compressed data and outputting the compressed data,
• converting the sampling sequences in the lines from time-domain signals into frequency-domain signals;
• performing, at one time, phase compensation processing for sub-Nyquist zones of the sampling sequences converted into the frequency-domain signals, and processing to cancel phase rotation due to delay time differences between the sampling sequences;
• determining into which sub-Nyquist zone the target signal has been folded and estimating a frequency of the target signal;
• and
• converting a value representing the sub-Nyquist zone and a corresponding amplitude value into the compressed data in a specified data format and outputting the compressed data, wherein
• the control circuit causes the data compression apparatus to further perform
• sampling the target signal at a sampling rate of the Nyquist rate, and
• extracting signals corresponding to specified delay time differences from the sampled target signal.

A non-transitory computer-readable storage medium storing a program to control a data compression apparatus,

• the program causing the data compression apparatus to perform:
• outputting sampling sequences corresponding to signals obtained by adding different delay times to different signals obtained by branching a target signal into a plurality of lines, and sampling the signals at a sampling rate of a Nyquist rate;
• and
• converting the sampling sequences into compressed data and outputting the compressed data, and
• causing the data compression apparatus to perform:
• as converting the sampling sequences into compressed data and outputting the compressed data,
• converting the sampling sequences in the lines from time-domain signals into frequency-domain signals;
• performing, at one time, phase compensation processing for sub-Nyquist zones of the sampling sequences converted into the frequency-domain signals, and processing to cancel phase rotation due to delay time differences between the sampling sequences;
• determining into which sub-Nyquist zone the target signal has been folded and estimating a frequency of the target signal;
• and
• converting a value representing the sub-Nyquist zone and a corresponding amplitude value into the compressed data in a specified data format and outputting the compressed data, wherein
• the program causes the data compression apparatus to further perform
• sampling the target signal at a sampling rate of the Nyquist rate, and
• extracting signals corresponding to specified delay time differences from the sampled target signal.

A data compression method in a data compression apparatus, the data compression method comprising:

• outputting, by a receiver, sampling sequences corresponding to signals obtained by adding different delay times to different signals obtained by branching a target signal into a plurality of lines, and sampling the signals at a sampling rate-less than of a Nyquist rate;
• and
• converting, by an encoder, the sampling sequences into compressed data and outputting, by the encoder, the compressed data,
• outputting the compressed data including
• converting, by a time-frequency transform circuitry, the sampling sequences in the lines from time-domain signals into frequency-domain signals,
• performing, by a signal processing circuitry, at one time, phase compensation processing for sub-Nyquist zones of the sampling sequences converted into the frequency-domain signals, and processing to cancel phase rotation due to delay time differences between the sampling sequences,
• determining, by a target frequency estimator, into which sub-Nyquist zone the target signal has been folded and estimating, by the target frequency estimator, a frequency of the target signal, and
• converting, by an encoding circuitry, a value representing the sub-Nyquist zone and a corresponding amplitude value into the compressed data in a specified data format and outputting, by the encoding circuitry, the compressed data, wherein
• the data compression method further comprises
• sampling, by a sampling circuitry, the target signal at a sampling rate of the Nyquist rate, and
• extracting, by a signal extraction circuitry, signals corresponding to specified delay time differences from a signal sampled by the sampling circuitry.