JP2000324188A - Synchronous generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generates accurate synchronizing signal even when a modulation signal is unclear and estimate the modulated signal without influenced by the moderation system gain change, and an error factor. SOLUTION: A delay part 102 delays the received power of a received signal for a fixed time, a difference operating part 103 operates the difference between the received power and the delayed delay received power, operated results cumulatively added by an adding part 104 are stored in a storing part while changing storage destinations in every fixed interval, a retrieving part 108 retrieves a place corresponding to a specified condition in stored information, and a synchronizing signal generating part 109 generates a synchronizing signal corresponding to the retrieval place. Thus, synchronous timing being suitable to detection can be generated from a received signal, and synchronous capture can be performed with high accuracy without depending on a modulation system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique used for digital communication, and more particularly to a technique relating to a synchronous generation method.

[0002]

2. Description of the Related Art In digital communication, various methods have been adopted for synchronizing to greatly influence reception characteristics. A method utilizing the instantaneous power distribution, which is a characteristic of the modulation method, is also known in Japanese Patent Application Laid-Open No. 7-162467. This method is used as a method for stably obtaining a highly accurate synchronization result even in an environment where received power is low.

[0003]

However, the conventional synchronous system is a system utilizing characteristics of a modulation system, for example, an instantaneous power distribution, and is used for complex modulation in which information is multiplexed into amplitudes such as multilevel quadrature modulation. Is difficult to deal with,
In the receiving apparatus, there is a problem that the characteristic is deteriorated when there is an error factor such as a gain change and a DC offset.

[0004]

In order to solve this problem, the present invention focuses on the instantaneous change amount, and this distribution has a large correlation with the symbol rate in a general modulation method represented by linear modulation. Use that thing. Since the distribution of the instantaneous change amount is used as a material for judging synchronization, a synchronization method having a great advantage that it is not influenced by a modulation method and is resistant to a gain change and an error factor is provided. Further, since the synchronization method is not affected by the modulation method, an accurate synchronization signal can be created even when the modulation signal is unknown, and the estimation of the modulation signal is also possible.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An invention according to claim 1 of the present invention is a system used for digital communication, wherein a power detector for detecting the power of a received signal and a delay unit for delaying the received power for a predetermined time. A difference calculating unit for calculating a difference between the received power and the delayed received power, an adding unit for performing cumulative addition, a storage unit for storing the result of the cumulative addition, and a time control unit for managing a fixed time interval And a storage control unit that changes the storage destination at regular intervals generated by the time control unit, a search unit that searches for a location corresponding to a specific condition from stored information, and generates a synchronization signal according to the search location. This is a synchronization generation system that generates a synchronization timing optimal for detection from a received signal, and has an effect that synchronization can be acquired with high accuracy regardless of the modulation system.

According to a fifth aspect of the present invention, there is provided a system used in digital communication, comprising: a delay unit for delaying a reception signal for a predetermined time; and a difference calculation unit for calculating a difference between the reception signal and the delayed delay signal. A power calculation unit that calculates the power of the result of the difference calculation, an addition unit that performs cumulative addition, a storage unit that stores the calculation result of the cumulative addition, a time control unit that manages a fixed time interval, and a time control unit. A storage control unit that changes the storage destination at regular intervals to be issued, a search unit that searches for a location corresponding to a specific condition from stored information, and a synchronization signal generation unit that generates a synchronization signal according to the search location. Consisting of
This is a synchronization generation method that generates an optimum synchronization timing for detection from a received signal, and has an effect that synchronization can be acquired with high accuracy regardless of the modulation method.

According to a ninth aspect of the present invention, there is provided a system used in digital communication, comprising: a quadrature demodulator for quadrature demodulating a received signal; a delay unit for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; A difference calculator for calculating the difference between the baseband signal and the delayed delay signal, a difference calculator for calculating the difference between the received signal and the delayed delay signal, and power for calculating the power of the difference baseband signal obtained by the difference calculation An operation unit, an addition unit for performing cumulative addition, a storage unit for storing the result of the cumulative addition, a time control unit for managing a fixed time interval, a storage control unit for changing a storage destination at fixed time intervals, and a storage unit. A search unit that searches for a location corresponding to a specific condition from the received information, and a synchronization signal generation unit that generates a synchronization signal according to the search location. A synchronization generation method of generating a ring has the effect that it is possible synchronization acquisition with high precision irrespective of the modulation scheme.

According to a thirteenth aspect of the present invention, there is provided a system used in digital communication, comprising: a quadrature demodulator for quadrature demodulating a received signal; a delay unit for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; A difference calculator for calculating a difference between the baseband signal and the delayed delay signal, a difference calculator for calculating a difference between the received signal and the delayed delay signal, and calculating an absolute value of the difference calculated baseband signal An absolute value calculation unit, an addition unit that calculates the sum of the absolute values of the two difference baseband signals, an addition unit that performs cumulative addition,
A storage unit that stores the operation result of the cumulative addition, a time control unit that manages a fixed time interval, a storage control unit that changes the storage destination at fixed time intervals generated by the time control unit, and A synchronization generation method that includes a search unit that searches for a portion corresponding to a specific condition, and a synchronization signal generation unit that generates a synchronization signal according to the search location, and generates an optimum synchronization timing for detection from a received signal. This has the effect that synchronous acquisition can be performed with high accuracy regardless of the modulation method.

The invention according to claim 17 is a system used in digital communication, wherein a power detector for detecting the power of a received signal, a delay unit for delaying the received power for a predetermined time, and a delay unit for delaying the received power. A difference calculation unit for calculating the difference between the delayed received powers, an addition unit for cumulative addition, a storage unit for storing the result of the cumulative addition, a time control unit for managing a fixed time interval, and a time control unit. A storage control unit that changes the storage destination at regular intervals, a search unit that searches for a location that meets specific conditions from stored information, and a synchronization signal generation unit that generates a synchronization signal according to the search location, A quadrature demodulation unit for quadrature demodulation of a received signal, a signal distribution detection unit for generating a signal distribution from a quadrature demodulation signal at a synchronous position, and a modulation signal estimation unit for estimating a modulation signal from the signal distribution. With estimating the items, a synchronization method for generating an optimal synchronization timing detection, also the modulation scheme is unknown reception signal, has an effect of enabling synchronization acquisition, estimates the modulation scheme.

According to a twenty-first aspect of the present invention, there is provided a system used in digital communication, comprising: a quadrature demodulator for quadrature demodulating a received signal; a delay unit for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; A difference calculator for calculating the difference between the baseband signal and the delayed delay signal, a difference calculator for calculating the difference between the received signal and the delayed delay signal, and power for calculating the power of the difference baseband signal obtained by the difference calculation An operation unit, an addition unit for performing cumulative addition, a storage unit for storing the result of the cumulative addition, a time control unit for managing a fixed time interval, a storage control unit for changing a storage destination at fixed time intervals, and a storage unit. A search unit that searches for a portion corresponding to a specific condition from the obtained information, a synchronization signal generation unit that generates a synchronization signal corresponding to the search location, and a signal distribution from the orthogonal baseband signal at the synchronization position. A modulation generation unit that generates a modulation signal from a signal distribution, estimates a modulation signal from a received signal, and generates a synchronization timing optimal for detection. Even if the received signal is unknown, it has the effect of enabling synchronization acquisition and estimating the modulation method.

According to a twenty-fifth aspect of the present invention, there is provided a system used in digital communication, comprising: a quadrature demodulator for quadrature demodulating a received signal; a delay unit for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; A difference calculator for calculating a difference between the baseband signal and the delayed delay signal, a difference calculator for calculating a difference between the received signal and the delayed delay signal, and calculating an absolute value of the difference calculated baseband signal An absolute value calculation unit, an addition unit that calculates the sum of the absolute values of the two difference baseband signals, an addition unit that performs cumulative addition,
A storage unit that stores the operation result of the cumulative addition, a time control unit that manages a fixed time interval, a storage control unit that changes the storage destination at fixed time intervals generated by the time control unit, and A search unit that searches for a location corresponding to a specific condition; a synchronization signal generation unit that generates a synchronization signal according to the search location; a distribution generation unit that generates a signal distribution from a received signal at the synchronization position; and a modulation signal from the signal distribution And a modulation signal estimator that estimates the modulation signal from the received signal, and generates a synchronization timing that is optimal for detection. , The modulation scheme is estimated.

An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) An embodiment of the first invention will be described with reference to FIG.

The received power of the received signal 150 is detected by the power detector 101, and a received power signal 151 is output.
This signal is delayed for a predetermined time by the delay unit 102, and a delayed signal 152 is output. The difference calculator 103 obtains a difference power signal 153 that is an instantaneous power change amount of the received power signal 151 and the delay signal 152.

The time control unit 107 manages the time of the system, and the storage control unit 106 stores the sample time information 156
Output a table address 155 indicating the element of the table of the storage unit 105 corresponding to the timing.

The differential power signal 153 is the table address 1
The immediately preceding table information 158 indicated by 55 and the adder 10
4 to output a power accumulation signal 154. The power accumulation signal 154 is updated as table information in the storage unit 105.

The search unit 108 searches all information in the table information 158 output from the storage unit 105 for a predetermined condition (for example, a minimum, a maximum, a difference of a 1/2 symbol interval is a maximum, and a minimum here, ), And the search result 159 is output. The synchronization signal generation unit 109 outputs a symbol synchronization signal 160 synchronized with the symbol timing of the received signal from the system timing 157 output from the time control unit 107 and the search result 159.

The present system utilizes the fact that the instantaneous change amount of a digitally modulated signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation.

For this reason, there is a great feature that synchronization can be achieved without particularly selecting a digital modulation method.
Since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, there is a feature that the characteristics are not affected by the DC offset.

Further, by replacing the power detection unit 101 with a frequency detection unit that changes the output depending on the frequency, it is possible to cope with a non-linear modulation method such as FSK.

As described above, the condition to be searched by the search unit 108 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective.

On the other hand, a method of searching for the maximum power is also conceivable because the time to be synchronized is a half cycle from the maximum power. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

(Embodiment 2) An embodiment of the second invention will be described with reference to FIG. Received signal 250 is delayed by delay section 201 for a fixed time, and delayed signal 260 is output. The difference calculation unit 202 outputs a difference reception signal 251 which is an instantaneous change amount between the reception signal 250 and the delay signal 260. The difference reception signal 252 output by the difference calculation unit 202 outputs a difference power signal 252 that is an instantaneous power change amount by the power calculation unit 203.

The time control unit 207 manages the time of the system, and the storage control unit 206 stores the sample time information 255
Outputs a table address 254 indicating the element of the table of the storage unit 205 corresponding to the timing.

The difference power signal 253 is the table address 2
The immediately preceding table information 256 indicated by 54 and the adder 2
In step 04, the cumulative addition is performed to output a power accumulation signal 253.
This power accumulation signal 253 is updated as table information in the storage unit 205.

The search unit 208 retrieves from all the information in the table information 256 output from the storage unit 205 a condition given in advance (for example, a minimum, a maximum, a difference of a 1/2 symbol interval is a maximum, and a minimum in this case. ), And a search result 258 is output. The synchronization signal generation unit 209 outputs a symbol synchronization signal 259 synchronized with the symbol timing of the received signal based on the system timing 257 output from the time control unit 207 and the search result 258.

The present system utilizes the fact that the instantaneous change amount of the digitally modulated signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation.

For this reason, there is a great feature that synchronization can be obtained without selecting a digital modulation method, and
Since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, there is a feature that the characteristics are not affected by the DC offset.

As described above, the condition to be searched by the search unit 208 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective. Conversely, a method of searching for the maximum power is also conceivable from the relationship that a point shifted from the maximum power by a half cycle is the time to be synchronized. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

(Embodiment 3) An embodiment of the third invention will be described with reference to FIG.

Received signal 350 is orthogonally demodulated by orthogonal demodulation section 301 and orthogonal baseband signal 351 is output. The orthogonal baseband signal 351 is delayed for a predetermined time by the delay unit 302, and a delayed signal 352 is output.

The orthogonal baseband signal 351 and the delay signal 3
52 outputs a difference baseband signal 353, which is an instantaneous change vector, from the difference calculation unit 303. The difference baseband signal 353 output from the difference calculation unit 303 outputs a difference power signal 354 that is an instantaneous power change amount from the power calculation unit 304.

The time control unit 308 manages the time of the system, and the storage control unit 307 stores the sample time information 357
Output a table address 356 indicating the element of the table in the storage unit 306 corresponding to the timing.

The difference power signal 354 is the table address 3
The immediately preceding table information 358 indicated by 56 is
At 05, a cumulative addition is performed to output a power accumulation signal 355.
The power accumulation signal 355 is updated as table information in the storage unit 306.

The search unit 309 uses all information in the table information 358 output from the storage unit 306 to determine the conditions given in advance (for example, the minimum, maximum, and the difference between 1/2 symbol intervals are maximum, ), And a search result 360 is output.

The synchronizing signal generator 310 has a time controller 308
Then, a symbol synchronization signal 361 synchronized with the symbol timing of the received signal is output from the system timing 359 and the search result 360 output in step (1).

The present system utilizes the fact that the instantaneous change amount of the digital modulation signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation. For this reason, in particular, there is a great feature that synchronization can be obtained without selecting a digital modulation method.In addition, since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, it is not affected. Features such as being unaffected by characteristics.

As described above, the condition to be searched by the search unit 309 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective.

On the other hand, a method of searching for the maximum power is conceivable because the time to be synchronized is a point shifted by half a cycle from the maximum power. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

(Embodiment 4) An embodiment of the fourth invention will be described with reference to FIG.

Received signal 450 is orthogonally demodulated by orthogonal demodulation section 401 and orthogonal baseband signal 451 is output. The orthogonal baseband signal 451 is delayed by the delay unit 402 for a fixed time, and a delayed signal 452 is output. The difference calculation unit 403 outputs a difference baseband signal 453 which is an instantaneous change vector from the orthogonal baseband signal 451 and the delay signal 452.

The difference baseband signal 453 output by the difference calculator 403 outputs a difference absolute value signal 454 as an instantaneous change amount by the absolute value calculator 404.

The time control unit 408 manages the time of the system, and the storage control unit 407 stores the sample time information 457.
Output the table address 456 indicating the element of the table of the storage unit 406 corresponding to the timing.

The difference absolute value signal 454 and the immediately preceding table information 458 indicated by the table address 456 are cumulatively added by the adder 405, and an absolute value cumulative signal 455 is output. This absolute value accumulation signal 455 is updated as table information in the storage unit 406.

The search unit 409 searches all information in the table information 458 output from the storage unit 406 for a condition given in advance (for example, a minimum, a maximum, a difference between 1/2 symbol intervals is a maximum, ), And a search result 460 is output. The synchronization signal generation unit 410 outputs a symbol synchronization signal 461 synchronized with the symbol timing of the received signal based on the system timing 459 output from the time control unit 408 and the search result 460.

This system utilizes the fact that the instantaneous change amount of the digital modulation signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation.

Therefore, there is a great feature that synchronization can be obtained without selecting a digital modulation method.
Since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, there is a feature that the characteristics are not affected by the DC offset.

As described above, the condition to be searched by the search unit 409 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective.

On the other hand, a method of searching for the maximum power is conceivable because the time to be synchronized is a half cycle from the maximum power. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

(Embodiment 5) An embodiment of the fifth invention will be described with reference to FIG.

The reception power of the reception signal 550 is detected by the power detection section 501, and a reception power signal 551 is output.
This signal is delayed for a predetermined time by the delay unit 502, and a delayed signal 552 is output. The difference calculation unit 503 calculates a difference power signal 553 that is an instantaneous power change amount of the reception power signal 551 and the delay signal 552.

The time control unit 507 manages the time of the system, and the storage control unit 506 stores the sample time information 556.
Outputs a table address 555 indicating the element of the table in the storage unit 505 corresponding to the timing.

The difference power signal 553 is the table address 5
The immediately preceding table information 558 indicated by 55 and the adder 50
In step 4, the cumulative addition is performed, and a power accumulation signal 554 is output. The power accumulation signal 554 is updated as table information in the storage unit 505.

The search unit 508 uses all the information in the table information 558 output from the storage unit 505 to determine the conditions given in advance (for example, the minimum, maximum, and the difference between 1/2 symbol intervals are maximum, ), And the search result 559 is output. The synchronization signal generation unit 509 outputs a symbol synchronization signal 560 synchronized with the symbol timing of the received signal based on the system timing 557 output from the time control unit 507 and the search result 559.

The received signal 550 is output to a quadrature demodulator 510.
, And a quadrature baseband signal 561 is output. The orthogonal demodulation signal 561 is sampled at each symbol timing by a symbol synchronization signal 560 synchronized with the symbol timing, and the signal distribution information 562 is output by the signal distribution detection unit 511.

The modulation signal estimating section 512 estimates the modulation method of the received signal 550 from the characteristics in the signal distribution information 562 and outputs the modulation method information 563.

This system utilizes the fact that the instantaneous change amount of the digital modulation signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation.

For this reason, there is a great feature that synchronization can be obtained without selecting a digital modulation method, and
Since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, there is a feature that the characteristics are not affected by the DC offset.

Further, by replacing the power detection unit 501 with a frequency detection unit that changes the output depending on the frequency, it is possible to cope with a non-linear modulation method such as FSK.

As described above, the condition to be searched by the search unit 508 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective.

On the other hand, a method of searching for the maximum power is conceivable because the time to be synchronized is a half cycle from the maximum power. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

When the modulation scheme of the received signal is unknown, the symbol rate is often unknown. This estimation method can be converted from the band of the spectrum of the received signal, but here, this does not specify a method for estimating the symbol rate, and various symbol rate estimation methods can be applied to this method. It is obvious.

(Embodiment 6) An embodiment of the sixth invention will be described with reference to FIG.

Received signal 650 is orthogonally demodulated by orthogonal demodulation section 601 to output orthogonal baseband signal 651. The orthogonal baseband signal 651 is delayed by the delay unit 602 for a fixed time, and a delayed signal 652 is output. From the orthogonal baseband signal 651 and the delayed signal 652, a difference calculation unit 603 outputs a difference baseband signal 653 which is an instantaneous change vector.

The difference baseband signal 653 output by the difference calculator 603 outputs a difference power signal 654 which is an instantaneous power change amount by the power calculator 604.

The time control unit 608 manages the time of the system, and the storage control unit 607 stores the sample time information 657.
Output a table address 656 indicating the element of the table of the storage unit 606 corresponding to the timing.

The difference power signal 654 is set to the table address 6
The immediately preceding table information 658 indicated by 56
At 05, the cumulative addition is performed and the power accumulation signal 655 is output.
This power accumulation signal 655 is updated as table information in the storage unit 606.

The search unit 609 uses all information in the table information 658 output from the storage unit 606 to determine the conditions given in advance (for example, the minimum, maximum, and the difference between 1/2 symbol intervals are maximum, ), And a search result 660 is output.

The synchronization signal generator 610 includes a time controller 608
A symbol synchronization signal 661 synchronized with the symbol timing of the received signal is output from the system timing 659 and the search result 660 which are output in step (1).

The orthogonal baseband signal 651 orthogonally demodulated by the orthogonal demodulation unit 601 is sampled at each symbol timing by a symbol synchronization signal 661 synchronized with the symbol timing, and the signal distribution information 662 is output by the signal distribution detection unit 611. Is done. The modulation signal estimating section 612 estimates the modulation scheme of the received signal 650 from the characteristics in the signal distribution information 662 and outputs modulation scheme information 663.

This system utilizes the fact that the instantaneous change amount of the digital modulation signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation.

For this reason, there is a great feature that synchronization can be obtained without selecting a digital modulation method.
Since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, there is a feature that the characteristics are not affected by the DC offset.

As described above, the condition to be searched by the search unit 609 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective.

On the other hand, a method of searching for the maximum power is also conceivable because the time to be synchronized is a point shifted by half a cycle from the maximum power. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

When the modulation scheme of the received signal is unknown, the symbol rate is often unknown. This estimation method can be converted from the band of the spectrum of the received signal, but here, this does not specify a method for estimating the symbol rate, and various symbol rate estimation methods can be applied to this method. It is obvious.

(Embodiment 7) An embodiment of the seventh invention will be described with reference to FIG.

Received signal 750 is orthogonally demodulated by orthogonal demodulation section 701 to output orthogonal baseband signal 751. The orthogonal baseband signal 751 is delayed by the delay unit 702 for a fixed time, and a delayed signal 752 is output. From the orthogonal baseband signal 751 and the delayed signal 752, a difference calculation unit 703 outputs a difference baseband signal 753 which is an instantaneous change vector.

The difference baseband signal 753 output from the difference calculation section 703 outputs a difference absolute value signal 754 which is an instantaneous change amount from the absolute value calculation section 704.

The time control unit 708 manages the time of the system, and the storage control unit 707 stores the sample time information 757.
Outputs a table address 756 indicating the element of the table in the storage unit 706 corresponding to the timing.

The difference absolute value signal 754 and the immediately preceding table information 758 indicated by the table address 756 are cumulatively added by the adder 705, and the absolute value cumulative signal 755 is output. This absolute value accumulation signal 755 is updated as table information in the storage unit 706.

The search unit 709 searches all information in the table information 758 output from the storage unit 706 for a condition given in advance (for example, a minimum, maximum, a difference of 1/2 symbol interval is maximum, and ) And a search result 760 is output. The synchronization signal generation unit 710 outputs a symbol synchronization signal 761 synchronized with the symbol timing of the received signal based on the system timing 759 output from the time control unit 708 and the search result 760.

The orthogonal baseband signal 751 orthogonally demodulated by the orthogonal demodulation unit 701 is sampled at each symbol timing by a symbol synchronization signal 761 synchronized with the symbol timing, and the signal distribution information 762 is output by the signal distribution detection unit 711. Is done. The modulation signal estimating section 712 estimates the modulation scheme of the received signal 750 from the characteristics in the signal distribution information 762 and outputs modulation scheme information 763.

This system utilizes the fact that the instantaneous variation of the digitally modulated signal has a high correlation with the symbol rate. This is because GMSK modulation, which is mainly used for digital communication, This is a feature common to linear modulation systems represented by phase modulation and quadrature amplitude modulation.

For this reason, there is a great feature that synchronization can be obtained without selecting a digital modulation method, and
Since the instantaneous change amount is used as a material for judging symbol synchronization, even if a DC offset exists in the power value used for detection, there is a feature that the characteristics are not affected by the DC offset.

As described above, the condition to be searched by the search unit 709 is not limited to one, and various conditions can be considered. Above all, the characteristic of the general linear modulation method is that the power at the time to be synchronized is minimized, so that the method of searching for the minimum power is effective. Conversely, a method of searching for the maximum power is also conceivable from the relationship that a point shifted from the maximum power by a half cycle is the time to be synchronized. Furthermore, the time to be synchronized can also be estimated by searching for the time at which the difference between the powers shifted by half a cycle becomes maximum.

When the modulation scheme of a received signal is unknown, its symbol rate is often unknown. This estimation method can be converted from the band of the spectrum of the received signal, but here, this does not specify a method for estimating the symbol rate, and various symbol rate estimation methods can be applied to this method. It is obvious.

[0087]

As described above, according to the present invention, in addition to the advantageous effects that stable acquisition can be performed without being affected by DC offset, gain and modulation signals, which is used for digital communication, modulation signals can be obtained. It is possible to estimate the modulation method at the same time as accurate synchronization even if the value is unknown.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram according to a first embodiment of the present invention;

FIG. 2 is a block circuit diagram according to a second embodiment of the present invention;

FIG. 3 is a block circuit diagram according to a third embodiment of the present invention.

FIG. 4 is a block circuit diagram according to a fourth embodiment of the present invention.

FIG. 5 is a block circuit diagram according to a fifth embodiment of the present invention.

FIG. 6 is a block circuit diagram according to a sixth embodiment of the present invention.

FIG. 7 is a block circuit diagram according to a seventh embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 power detection unit 102 delay unit 103 difference calculation unit 104 addition unit 105 storage unit 106 storage control unit 107 time control unit 108 search unit 109 synchronization signal generation unit 150 reception signal 151 reception power signal 152 delay signal 153 difference power signal 154 power accumulation Signal 155 Table address 156 Sample time information 157 System timing 158 Table information 159 Search result 160 Symbol synchronization signal 201 Delay unit 202 Difference calculation unit 203 Power calculation unit 204 Addition unit 205 Storage unit 206 Storage control unit 207 Time control unit 208 Search unit 209 Synchronization signal generator 250 Received signal 251 Differential received signal 252 Differential power signal 253 Power accumulated signal 254 Table address 255 Sample time information 256 Table information 257 System timing 258 Search result 259 Symbol synchronization signal 260 Delay signal 301 Quadrature demodulation unit 302 Delay unit 303 Difference calculation unit 304 Power calculation unit 305 Addition unit 306 Storage unit 307 Storage control unit 308 Time control unit 309 Search unit 310 Synchronization signal generation unit 350 Reception Signal 351 Quadrature baseband signal 352 Delay signal 353 Difference baseband signal 354 Difference power signal 355 Power accumulation signal 356 Table address 357 Sample time information 358 Table information 359 System timing 360 Search result 361 Symbol synchronization signal 401 Quadrature demodulation unit 402 Delay unit 403 Difference calculation unit 404 Absolute value calculation unit 405 Addition unit 406 Storage unit 407 Storage control unit 408 Time control unit 409 Search unit 410 Synchronization signal generation unit 450 Received signal 451 Sband signal 452 Delay signal 453 Difference baseband signal 454 Difference absolute value signal 455 Absolute value accumulation signal 456 Table address 457 Sample time information 458 Table information 459 System timing 460 Search result 461 Symbol synchronization signal 501 Power detection unit 502 Delay unit 503 Difference operation Unit 504 addition unit 505 storage unit 506 storage control unit 507 time control unit 508 search unit 509 synchronization signal generation unit 510 quadrature demodulation unit 511 signal distribution detection unit 512 modulation signal estimation unit 550 reception signal 551 reception power signal 552 delay signal 553 differential power Signal 554 Power accumulation signal 555 Table address 556 Sample time information 557 System timing 558 Table information 559 Search result 560 Symbol synchronization signal 561 Quadrature base Band signal 562 Signal distribution information 563 Modulation method information 601 Quadrature demodulation unit 602 Delay unit 603 Difference calculation unit 604 Power calculation unit 605 Addition unit 606 Storage unit 607 Storage control unit 608 Time control unit 609 Search unit 610 Synchronous signal generation unit 611 Signal distribution Detector 612 Modulated signal estimator 650 Received signal 651 Quadrature baseband signal 652 Delay signal 653 Difference baseband signal 654 Difference power signal 655 Power accumulation signal 656 Table address 657 Sample time information 658 Table information 659 System timing 660 Search result 661 Symbol synchronization Signal 662 Signal distribution information 663 Modulation method information 701 Quadrature demodulation unit 702 Delay unit 703 Difference calculation unit 704 Absolute value calculation unit 705 Addition unit 706 Storage unit 707 Storage control unit 708 Inter-control unit 709 search unit 710 synchronization signal generation unit 711 signal distribution detection unit 712 modulation signal estimation unit 750 reception signal 751 orthogonal baseband signal 752 delay signal 753 difference baseband signal 754 difference absolute value signal 755 absolute value accumulation signal 756 table address 757 Sample time information 758 Table information 759 System timing 760 Search result 761 Symbol synchronization signal 762 Signal distribution information 763 Modulation method information

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yutaka Murakami 3-10-1 Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa Prefecture Inside Matsushita Giken Co., Ltd. (72) Inventor Akihiko Matsuoka 3-chome, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa No. 10 Matsushita Giken Co., Ltd. (72) Inventor Morikazu Sagawa 3-10-1, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa F-term inside Matsushita Giken Co., Ltd. MM24 MM36

Claims (30)

[Claims] 1. A method used for digital communication, comprising: a power detection unit for detecting the power of a received signal; a delay unit for delaying the received power for a predetermined time; and a difference between the received power and the delayed received power. A difference calculation unit for performing calculation, an addition unit for performing cumulative addition, a storage unit for storing the result of the cumulative addition, a time control unit for managing a fixed time interval, and a storage destination for each fixed time generated by the time control unit. It consists of a storage control unit to change, a search unit to search the stored information for a part corresponding to a specific condition, and a synchronization signal generation unit to generate a synchronization signal according to the searched part. Synchronization generation method that generates the optimal synchronization timing. 2. The synchronization generation method according to claim 1, wherein the specific condition of the search unit is a minimum value among the stored information. 3. The synchronization generation method according to claim 1, wherein the specific condition of the search unit is a maximum value among the stored information. 4. The synchronization generation method according to claim 1, wherein a search is made for a condition having a maximum difference of half the symbol time. 5. A method used for digital communication, comprising: a delay unit for delaying a received signal for a predetermined time; a difference calculation unit for calculating a difference between the received signal and the delayed delay signal; , An adder that performs cumulative addition, a storage that stores the result of the cumulative addition, a time controller that manages a fixed time interval, and a storage destination that is generated by the time controller at regular intervals. And a synchronization signal generation unit that generates a synchronization signal corresponding to the search location from the received signal. Synchronous generation method that generates optimal synchronous timing for detection. 6. The synchronization generation method according to claim 5, wherein the specific condition of the search unit is a minimum value among the stored information. 7. The synchronization generation method according to claim 5, wherein the specific condition of the search unit is a maximum value among the stored information. 8. The synchronization generation method according to claim 5, wherein a condition having a maximum difference between half the symbol times is searched. 9. A method used for digital communication, comprising: a quadrature demodulation section for quadrature demodulating a received signal; a delay section for delaying a quadrature demodulated quadrature baseband signal for a fixed time; and a quadrature baseband signal delayed. A difference calculation unit for calculating the difference between the delayed signals, a difference calculation unit for calculating the difference between the received signal and the delayed delay signal, a power calculation unit for calculating the power of the difference baseband signal obtained by the difference calculation, and cumulative addition An addition unit, a storage unit that stores the operation result of the cumulative addition, a time control unit that manages a fixed time interval, a storage control unit that changes the storage destination at fixed time intervals, and a storage information that is specified from among the stored information. It consists of a search unit that searches for a location that meets the conditions and a synchronization signal generation unit that generates a synchronization signal according to the search location, and generates the optimal synchronization timing for detection from the received signal. Synchronous generation method. 10. The synchronization generation method according to claim 9, wherein the specific condition of the search unit is a minimum value among the stored information. 11. The synchronization generation method according to claim 9, wherein the specific condition of the search unit is a maximum value in the stored information. 12. The synchronization generation method according to claim 9, wherein a search is made for a condition having a maximum difference between half the symbol times. 13. A method used for digital communication, comprising: a quadrature demodulation section for quadrature demodulating a received signal; a delay section for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; and a quadrature baseband signal. A difference calculation unit for calculating the difference between the delayed signals, a difference calculation unit for calculating the difference between the received signal and the delayed delay signal, an absolute value calculation unit for calculating the absolute value of the difference baseband signal obtained by the difference calculation; An adder for calculating the sum of the absolute values of two difference baseband signals; an adder for performing cumulative addition; a storage for storing the result of the cumulative addition; a time controller for managing a fixed time interval; A storage control unit that changes the storage destination at fixed time intervals generated by the unit, a search unit that searches the stored information for locations that meet specific conditions, and generates a synchronization signal according to the searched locations That it consists of a synchronizing signal generating unit, synchronization generation method of generating an optimum synchronization timing detection from the received signal. 14. The synchronization generation method according to claim 13, wherein the specific condition of the search unit is a minimum value among the stored information. 15. The synchronization generation method according to claim 13, wherein the specific condition of the search unit is a maximum value among the stored information. 16. The synchronization generation method according to claim 13, wherein a search is made for a condition in which a difference between half the symbol times is maximum. 17. A method used for digital communication, comprising: a power detection unit for detecting the power of a received signal; a delay unit for delaying the received power for a predetermined time; and a difference between the received power and the delayed received power. A difference calculation unit for performing calculation, an addition unit for performing cumulative addition, a storage unit for storing the result of the cumulative addition, a time control unit for managing a fixed time interval, and a storage destination for each fixed time generated by the time control unit. A storage control unit to be changed; a search unit to search a location corresponding to a specific condition from stored information; a synchronization signal generation unit to generate a synchronization signal according to the search location; and a quadrature to orthogonally demodulate a received signal. A demodulation unit, a signal distribution detection unit that generates a signal distribution from a quadrature demodulated signal at a synchronous position, and a modulation signal estimation unit that estimates a modulation signal from the signal distribution, and estimates a modulation signal from a received signal Both synchronous generation method for generating an optimal synchronization timing detection. 18. The synchronization generation method according to claim 17, wherein the specific condition of the search unit is a minimum value among the stored information. 19. The synchronization generation method according to claim 17, wherein the specific condition of the search unit is a maximum value among the stored information. 20. The synchronization generation method according to claim 17, wherein a condition having a maximum difference between half the symbol times is searched. 21. A method used in digital communication, comprising: a quadrature demodulator for quadrature demodulating a received signal; a delay unit for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; and a quadrature baseband signal delayed. A difference calculation unit for calculating the difference between the delayed signals, a difference calculation unit for calculating the difference between the received signal and the delayed delay signal, a power calculation unit for calculating the power of the difference baseband signal obtained by the difference calculation, and cumulative addition An addition unit, a storage unit that stores the operation result of the cumulative addition, a time control unit that manages a fixed time interval, a storage control unit that changes the storage destination at fixed time intervals, and a storage information that is specified from among the stored information. A search unit that searches for a location that satisfies the conditions, a synchronization signal generation unit that generates a synchronization signal according to the search location, and a distribution generator that generates a signal distribution from the orthogonal baseband signal at the synchronization position A synchronization generation method comprising a modulation section and a modulation signal estimation section for estimating a modulation signal from a signal distribution, estimating a modulation signal from a received signal, and generating an optimal synchronization timing for detection. 22. The synchronization generation method according to claim 21, wherein the specific condition of the search unit is a minimum value among the stored information. 23. The synchronization generation method according to claim 21, wherein the specific condition of the search unit is a maximum value in the stored information. 24. The synchronization generation method according to claim 21, wherein a condition having a maximum difference between half the symbol times is searched. 25. A method used in digital communication, comprising: a quadrature demodulator for quadrature demodulating a received signal; a delay unit for delaying a quadrature demodulated quadrature baseband signal for a predetermined time; and a quadrature baseband signal delayed. A difference calculation unit for calculating the difference between the delayed signals, a difference calculation unit for calculating the difference between the received signal and the delayed delay signal, an absolute value calculation unit for calculating the absolute value of the difference baseband signal obtained by the difference calculation; An adder for calculating the sum of the absolute values of two difference baseband signals; an adder for performing cumulative addition; a storage for storing the result of the cumulative addition; a time controller for managing a fixed time interval; A storage control unit that changes the storage destination at fixed time intervals generated by the unit, a search unit that searches the stored information for locations that meet specific conditions, and generates a synchronization signal according to the searched locations A distribution signal generator for generating a signal distribution from a received signal at a synchronous position, and a modulation signal estimator for estimating a modulation signal from the signal distribution. Synchronous generation method that generates optimal synchronous timing for detection. 26. The synchronization generation method according to claim 25, wherein the specific condition of the search unit is a minimum value among the stored information. 27. The synchronization generation method according to claim 25, wherein the specific condition of the search unit is a maximum value in the stored information. 28. The synchronization generation method according to claim 25, wherein a condition having a maximum difference between half the symbol times is searched. 29. A demodulation device using the synchronization method according to claim 1. 30. A digital communication system using the synchronization method according to claim 1.