Granted Patent B2

US 12,375,192 · App. 17/984,368 · Granted Jul 29, 2025

Inventor: Yuji Akiyama (Tokyo, JP)

Assignee: MITSUBISHI ELECTRIC CORPORATION

H04B17/21H04B17/12H04B17/318

Abstract

Claims (92)

1. A data compression apparatus comprising:

a receiver to output 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

an encoder to convert the sampling sequences into compressed data and output the compressed data,

the encoder including

a time-frequency transform circuitry to convert the sampling sequences in the lines from time-domain signals into frequency-domain signals,

a signal processing circuitry to perform, 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,

a target frequency estimator to determine into which sub-Nyquist zone the target signal has been folded and estimate a frequency of the target signal, and

an encoding circuitry to convert a value representing the sub-Nyquist zone and a corresponding amplitude value into the compressed data in a specified data format and output the compressed data, wherein

the receiver includes

a sampling circuitry to sample the target signal at a sampling rate of the Nyquist rate, and

a signal extraction circuitry to extract signals corresponding to specified delay time differences from a signal sampled by the sampling circuitry.

2. The data compression apparatus according to claim 1 , wherein

the receiver includes

a delay time addition circuitry to add the different delay times to the different signals obtained by branching the target signal into the plurality of lines, and

a sub-sampling circuitry to sample the signals at the sampling rate less than the Nyquist rate and output the sampling sequences.

3. The data compression apparatus according to claim 2 , wherein

the delay time addition circuitry adds the delay times using a delay element or a track-and-hold circuit.

4. The data compression apparatus according to claim 1 , wherein

the encoder further includes

a window processing circuitry to multiply the sampling sequences in the lines output from the receiver by coefficients corresponding to Hann windows, and

the time-frequency transform circuitry converts the sampling sequences in the lines output from the window processing circuitry from time-domain signals into frequency-domain signals.

5. The data compression apparatus according to claim 1 , wherein

the encoder performs processing only on sub-Nyquist zones in which a valid signal can be present.

6. The data compression apparatus according to claim 1 , wherein

the target frequency estimator calculates a sum total of values obtained by multiplication by coefficients for each sub-Nyquist zone in the signal processing circuitry, and determines that the target signal is folded in a sub-Nyquist zone in which the largest sum total is obtained.

7. The data compression apparatus according to claim 1 , wherein

the target frequency estimator determines that the target signal is folded in a sub-Nyquist zone having the smallest variations in values obtained by multiplication by coefficients for each sub-Nyquist zone in the signal processing circuitry.

8. The data compression apparatus according to claim 1 , wherein

the encoder is a first encoder, and

the data compression apparatus further comprises a second encoder to compress the compressed data output from the first encoder.

9. The data compression apparatus according to claim 1 , wherein

the data compression apparatus comprises a plurality of the receivers, each of the plurality of receivers being connected to a different antenna,

a first receiver of the plurality of receivers outputs the sampling sequences of the target signal received by a primary antenna,

one or more second receivers of the plurality of receivers output the sampling sequences of the target signal received by secondary antennas,

the data compression apparatus further comprises one or more synthesizers connected to the corresponding second receivers, to calculate a sum total of amplitude components corresponding to a sub-Nyquist zone, using information on the sub-Nyquist zone acquired from the encoder, and output the sum total of the amplitude components to the encoder, and

the encoder is connected to the first receiver, outputs the information on the sub-Nyquist zone of the sampling sequences of the target signal received by the primary antenna, and outputs the compressed data obtained by compressing the sampling sequences of the target signal received by the primary antenna and the secondary antennas, using the sum totals of the amplitude components acquired from the synthesizers.

10. A data decompression apparatus comprising

a decoder to extract the value representing the sub-Nyquist zone and the corresponding amplitude value from the compressed data acquired from the data compression apparatus according to claim 1 , and restore an amplitude value corresponding to a frequency before the target signal is folded in the data compression apparatus.

11. The data decompression apparatus according to claim 10 , wherein

the encoder is a first encoder,

the decoder is a first decoder, and

the data decompression apparatus further comprises a second encoder to compress the compressed data output from the first encoder, and a second decoder to decode the compressed data acquired from the data compression apparatus.

12. The data decompression apparatus according to claim 10 , further comprising

a storage to store the compressed data acquired from the data compression apparatus.

13. The data decompression apparatus according to claim 10 , further comprising

a frequency-time transform circuitry to convert the value restored by the decoder from a frequency-domain signal into a time-domain signal.

14. A data compression system comprising:

the data compression apparatus according to claim 1 ; and

a data decompression apparatus including a decoder to extract the value representing the sub-Nyquist zone and the corresponding amplitude value from the compressed data acquired from the data compression apparatus, and restore an amplitude value corresponding to a frequency before the target signal is folded in the data compression apparatus.

15. 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.

16. A control circuit to control a data decompression apparatus, the control circuit causing the data decompression apparatus to perform

extracting the value representing the sub-Nyquist zone and the corresponding amplitude value from the compressed data acquired from the data compression apparatus according to claim 1 , and restoring an amplitude value corresponding to a frequency before the target signal is folded in the data compression apparatus.

17. 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.

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

the program causing the data decompression apparatus to perform

extracting the value representing the sub-Nyquist zone and the corresponding amplitude value from the compressed data acquired from the data compression apparatus according to claim 1 , and restoring an amplitude value corresponding to a frequency before the target signal is folded in the data compression apparatus.

19. 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.

20. A data decompression method in a data decompression apparatus, the data decompression method comprising

extracting, by a decoder, the value representing the sub-Nyquist zone and the corresponding amplitude value from the compressed data acquired from the data compression apparatus to perform the data compression method according to claim 19 , and restoring, by the decoder, an amplitude value corresponding to a frequency before the target signal is folded in the data compression apparatus.

Assignments (1)

Priority Claims (1)

Continuity (2)

References Cited (23)