Synchronization detection device, synchronization detection method, and synchronization detection program

Abstract

To provide a synchronization detection device, a synchronization detection method, and a synchronization detection program that can follow a frequency deviation of an intermediate frequency (IF) after down-converting a radio frequency in a short time.SOLUTION: A synchronization detection device 11 according to the present invention includes a band limiting unit 111 in which each of a plurality of filters 111a to 111e having different center frequencies for a received signal from the outside limits the band of a received signal and outputs a plurality of band-limited signals, a detection demodulation unit 112 that detects and demodulates each of the plurality of band-limited signals and outputs a plurality of detected signals, a synchronous detection unit 113 that synchronously detects each of the plurality of detection signals and outputs a plurality of correlation values, and a synchronization evaluation unit 114 that selects a predetermined filter 111p from among the plurality of filters 111a to 111e on the basis of the plurality of correlation values.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a synchronization detection device, a synchronization detection method, and a synchronization detection program, and in particular to a synchronization detection device, a synchronization detection method, and a synchronization detection program that can quickly track frequency deviations in intermediate frequencies (IF) after down-converting radio frequencies. [Background technology]

[0002] Automatic frequency control (AFC) in land mobile radio (LMR) reception involves converting the frequency of the received signal received by the receiver (RX) to an intermediate frequency (IF) using a frequency mixer. This changes the local (LO) frequency to track the frequency deviation of the received signal, and adjusts the output IF signal to the center frequency of the filter. This results in an IF signal that is minimally affected by the band limiting caused by the filter. However, there are issues with the time it takes to set the local frequency, and for the intermediate frequency determined by the received frequency and the local frequency to fall within the frequency band of the filter. Furthermore, since the receiving frequency differs for each communication terminal, the local frequency must be changed for each terminal, which also adds to the time it takes to set the frequency. The receiving frequency is sometimes called the carrier frequency.

[0003] Patent Document 1 describes a technique in which a repeater or base station detects error information of the signal frequency arriving on the uplink from a wireless communication device, and transmits the error information to the corresponding wireless communication device on the downlink, and the wireless communication device corrects its own oscillator frequency based on the error information.The technique described in Patent Document 1 obtains frequency error information on the uplink and notifies it on the downlink, so it takes time to track the frequency.

[0004] Patent Document 2 states that "an IF signal including an FM-modulated video signal is digitally converted by a DAC and then quadrature-modulated in a quadrature modulation section to generate components that are orthogonal to each other, and at the same time, down-converted to the baseband (BB) band. In this BB band, FM demodulation processing is performed using a phase calculation section and a phase difference detection section. For digital processing, an NCO (Numerical Control Oscillator) can be used as the local oscillator in the quadrature modulation section, facilitating adjustment and setting, and also facilitating subcarrier setting in the FM demodulation section for the audio signal, and changing the filter for subcarrier extraction is easy by simply changing the filter coefficient." The technology described in Patent Document 2 is a system that demodulates video signals and audio signals (subcarrier signals) in parallel, and does not disclose parallel detection and demodulation of multiple IF signals with slightly shifted frequencies. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-35132 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-110269 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, there was a problem in that it took time to bring the intermediate frequency determined by the reception frequency and the local frequency into the frequency band of the filter.

[0007] An object of the present invention is to provide a synchronization detection device, a synchronization detection method, and a synchronization detection program that solve the above-mentioned problems. [Means for solving the problem]

[0008] Therefore, the present invention provides: A plurality of filters each having a different center frequency for an externally received signal are used to a band limiting unit that limits the band of a signal and outputs a plurality of band-limited signals; A demodulator that detects and demodulates each of the plurality of band-limited signals and outputs a plurality of detected signals. With Chobe, a synchronous detection unit that synchronously detects each of the plurality of detection signals and outputs a plurality of correlation values; A predetermined filter is selected from the plurality of filters based on the plurality of correlation values. a synchronization evaluation unit; Equipped with 、 The synchronization evaluation unit is configured to set a center frequency of the filter based on the correlation value. a tracking unit and a filter coefficient setting unit, The synchronization evaluation unit sets the highest correlation value among the plurality of correlation values ​​as a first correlation value, selecting the predetermined filter corresponding to the first correlation value from among the number of filters, The frequency tracking unit detects a frequency deviation value of the selected predetermined filter, and The filter coefficient setting unit updates the center frequency of the predetermined filter based on the frequency deviation value. death, The band limiting unit outputs a predetermined band-limited signal using the updated predetermined filter. do, A synchronous detection device is provided.

[0009] The present invention also provides A plurality of filters each having a different center frequency for an externally received signal are used to limiting the band of the signal to output a plurality of band-limited signals; detecting and demodulating each of the plurality of band-limited signals to output a plurality of detected signals; , synchronously detecting each of the plurality of detection signals and outputting a plurality of correlation values; A predetermined filter is selected from the plurality of filters based on the plurality of correlation values. And, The highest correlation value among the plurality of correlation values ​​is defined as a first correlation value, and the highest correlation value among the plurality of filters is defined as a second correlation value. When the predetermined filter corresponding to the first correlation value is selected, the selected predetermined A frequency deviation value of a filter is detected, and a filter in the predetermined filter is selected based on the frequency deviation value. updating the cardiac frequency; outputting a predetermined band-limited signal using the updated predetermined filter; The present invention provides a synchronous detection method comprising:

[0010] The present invention also provides A plurality of filters each having a different center frequency for an externally received signal are used to limiting the band of the signal to output a plurality of band-limited signals; detecting and demodulating each of the plurality of band-limited signals to output a plurality of detected signals; , synchronously detecting each of the plurality of detection signals and outputting a plurality of correlation values; A predetermined filter is selected from the plurality of filters based on the plurality of correlation values. And, The highest correlation value among the plurality of correlation values ​​is defined as a first correlation value, and When the predetermined filter corresponding to the first correlation value is selected, the selected predetermined and detecting a frequency deviation value of the filter, and determining a frequency deviation value of the predetermined filter based on the frequency deviation value. updating the center frequency; outputting a predetermined band-limited signal using the updated predetermined filter; The present invention provides a synchronization detection program that causes a computer to execute the above. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a synchronization detection device, a synchronization detection method, and a synchronization detection program that can quickly track frequency deviations in an intermediate frequency (IF) after down-converting a radio frequency. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram illustrating a wireless communication device according to an embodiment. [Figure 2] 4 is a state transition diagram illustrating state transitions of a synchronization detection device according to an embodiment. FIG. [Figure 3] 1 is a block diagram illustrating a synchronization detection device according to an embodiment; [Figure 4] 3A and 3B are schematic diagrams illustrating frequency band characteristics of a filter according to an embodiment. [Figure 5] 3A and 3B are schematic diagrams illustrating frequency band characteristics of a received signal and a filter. [Figure 6] 3A and 3B are schematic diagrams illustrating frequency band characteristics of a received signal and a filter. [Figure 7] FIG. 10 is a schematic diagram illustrating a detected waveform of a synchronization symbol. [Figure 8] FIG. 10 is a schematic diagram illustrating a detected waveform of a synchronization symbol. [Figure 9] FIG. 10 is a schematic diagram illustrating a detected waveform of a synchronization symbol. [Figure 10] 1 is a block diagram illustrating a synchronization detection device according to an embodiment; [Figure 11] 1 is a block diagram illustrating a synchronization detection device according to an embodiment; [Figure 12] 10 is a flowchart illustrating the operation of the synchronization detection device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Embodiment Mode] FIG. 1 is a block diagram illustrating a wireless communication device according to an embodiment.

[0014] As shown in Fig. 1, a wireless communication device 10 according to the embodiment includes a receiving unit (RX), a frequency synthesizer unit (SYNTH), and a transmitting unit (TX). The frequency synthesizer unit has a voltage-controlled temperature-compensated crystal oscillator (VC-TCXO), a phase-locked loop (PLL), and a voltage-controlled oscillator (VCO). The frequency synthesizer unit uses these to supply an original signal for supplying a first local signal to frequency mixing unit 117a of the receiving unit. The frequency synthesizer unit also supplies a transmit local signal to frequency mixing unit 117t of the transmitting unit.

[0015] The transmitter includes a digital modulator 116t and a frequency mixer 117t. The digital modulator 116t modulates data to be transmitted and outputs the modulated signal to the frequency mixer 117t. The frequency mixer 117t upconverts the baseband modulated signal to a radio frequency and transmits the radio signal to an external terminal via an antenna.

[0016] The receiving unit has a frequency mixing unit 117a, a band limiting unit 118, a frequency mixing unit 117b, and a baseband unit 11b. The frequency mixing unit 117a down-converts (converts) a radio signal received via an antenna using a first local signal, and outputs a first intermediate frequency signal (1st IF signal). The band limiting unit 118 applies a band limit to the first intermediate frequency signal. The frequency mixing unit 117b down-converts the band-limited first intermediate frequency signal using a second local signal, and outputs a second intermediate frequency signal (2nd IF signal).

[0017] The baseband unit 11b can also operate as the synchronization detection device 11 by itself. Therefore, hereinafter, the baseband unit 11b will be described as the synchronization detection device 11, which is the baseband unit 11b alone. The synchronization detection device 11 (baseband unit 11b) includes a band limiting unit 111, a detection and demodulation unit 112, a synchronization detection unit 113, a synchronization evaluation unit 114, and a symbol detection unit 116. A detailed description of each unit of the synchronization detection device 11 will be given later.

[0018] FIG. 2 is a state transition diagram illustrating state transitions of the synchronization detection device according to the embodiment.

[0019] As shown in FIG. 2, the synchronization detection device 11 has two states: a standby state and a symbol detection state. The synchronization detection device 11 transitions to the symbol detection state when a predetermined condition is satisfied, and transitions to the standby state when the predetermined condition is not satisfied. The synchronization detection device 11 transitions (shifts) to the symbol detection state when the predetermined condition is satisfied, for example, when any of the multiple correlation values ​​output by the synchronization detection unit 113 is equal to or greater than a predetermined threshold. The synchronization detection device 11 (bandwidth limiting unit 111, detection / demodulation unit 112, synchronization detection unit 113, and synchronization evaluation unit 114) transitions to the standby state in which synchronization detection is repeated when the predetermined condition is not satisfied, for example, when all of the multiple correlation values ​​are less than a predetermined threshold. Furthermore, in the symbol detection state, the synchronization detection device 11 selects a predetermined filter, which will be described later.

[0020] The state in which any one of the correlation values ​​is equal to or greater than a predetermined threshold may be referred to as a "synchronization detected state," and the state in which all of the correlation values ​​are less than the predetermined threshold may be referred to as a "synchronization out state."

[0021] <Standby state> The operation of the synchronization detection device in the standby state will now be described.

[0022] FIG. 3 is a block diagram illustrating a synchronization detection device according to an embodiment. FIG. 3 is a block diagram illustrating the synchronization detection device in the standby state. 3, the band limiting unit 111x, the detection and demodulation unit 112x, and the synchronization detection unit 113x are grouped into one system, and an example will be described in which five such systems are provided, where x is any one of a, b, c, d, and e. FIG. 4 is a schematic diagram illustrating the frequency band characteristics of the filter according to the embodiment. The horizontal axis in FIG. 4 represents frequency.

[0023] 3, the synchronization detection device 11 includes a band limiting unit 111, a detection and demodulation unit 112, a synchronization detection unit 113, a synchronization evaluation unit 114, and a symbol detection unit. The synchronization detection unit may also be referred to as a SYNC detection unit, and the synchronization evaluation unit may also be referred to as a SYNC evaluation unit.

[0024] In the band-limiting unit 111, for example, a plurality of filters 111a to 111e having different center frequencies limit the band of a received signal (wireless signal) from an external terminal, and output a plurality of band-limited signals. The band-limiting unit 111 is configured, for example, with a plurality of filters having frequency band characteristics as shown in FIG. 4, with filters having center frequencies slightly shifted from one another arranged in parallel. The band-limiting unit 111 band-limits the received signal for each of the plurality of filters. FIG. 3 shows an example of the filter configuration of the band-limiting unit 111, in which five narrow-band filters whose center frequencies are shifted by 500 Hz (Hertz) are arranged in array. That is, in FIG. 3, the band-limiting unit 111 has a center frequency of 0 Hz as its center, a filter 111c, a -1 kHz shift filter 111e, a -500 Hz shift filter 111d, a +500 Hz shift filter 111b, and a +1 kHz shift filter 111a.

[0025] The filter may be, for example, an ACR (Adjacent Channel Rejection) filter. The ACR filter is a band pass filter that suppresses carriers in frequency bands adjacent to the pass frequency band. The ACR filter can be realized by a digital filter, which uses digital signal processing. By appropriately setting the filter coefficients, the center frequency and frequency bandwidth of the ACR filter can be set, allowing only the target band to pass (extract). Examples of digital filters include FIR (Finite Impulse Response) filters and IIR (Infinite Impulse Response) filters.

[0026] The detector / demodulator 112 detects and demodulates each of the plurality of band-limited signals to output a plurality of detected signals. Specifically, in the detector / demodulator 112, the detector / demodulator 112a detects and demodulates the band-limited signal output from the filter 111a, the detector / demodulator 112b detects and demodulates the band-limited signal output from the filter 111b, the detector / demodulator 112c detects and demodulates the band-limited signal output from the filter 111c, the detector / demodulator 112d detects and demodulates the band-limited signal output from the filter 111d, and the detector / demodulator 112e detects and demodulates the band-limited signal output from the filter 111e.

[0027] The synchronization detection unit 113 synchronously detects each of the plurality of detection signals and outputs a plurality of correlation values. The synchronization detection unit 113 generates a predetermined synchronization signal, performs synchronization detection based on the detection signals and the predetermined synchronization signal, and outputs a correlation value.

[0028] Specifically, in the synchronization detection unit 113, synchronization detector 113a synchronously detects the detection signal output from detection demodulator 112a, synchronization detector 113b synchronously detects the detection signal output from detection demodulator 112b, synchronization detector 113c synchronously detects the detection signal output from detection demodulator 112c, synchronization detector 113d synchronously detects the detection signal output from detection demodulator 112d, and synchronization detector 113e synchronously detects the detection signal output from detection demodulator 112e, and outputs correlation values ​​to synchronization evaluation unit 114. The correlation values ​​may also be referred to as symbol correlation values.

[0029] FIG. 5 is a schematic diagram illustrating the frequency band characteristics of a received signal and a filter. The horizontal axis in Fig. 5 represents frequency. Fig. 5 shows the frequency band characteristics when there is no deviation between the center frequency of the filter and the center frequency of the received signal (IF signal). FIG. 6 is a schematic diagram illustrating the frequency band characteristics of a received signal and a filter. The horizontal axis in Fig. 6 represents frequency. Fig. 6 shows the frequency band characteristics when there is a deviation between the center frequency of the filter and the center frequency of the received signal (IF signal).

[0030] 5, when there is no deviation between the center frequency of the filter and the center frequency of the received signal (when the received signal has no frequency deviation), the received signal is not subject to unnecessary band limitation. When there is no frequency deviation, the received signal is not subject to unnecessary band limitation, so the correlation value synchronously detected by synchronization detection unit 113 is higher than the correlation value when there is a frequency deviation.

[0031] 6, when there is a difference between the center frequency of the filter and the center frequency of the received signal (when the received signal has a frequency shift), the received signal is subjected to unnecessary band restriction. When there is a frequency shift, the received signal is subjected to unnecessary band restriction, and therefore the correlation value synchronously detected by synchronization detection unit 113 is lower than the correlation value when there is no frequency shift.

[0032] The synchronization evaluation unit 114 selects a predetermined filter 111p from among the plurality of filters 111a to 111e based on the plurality of correlation values. In a standby state, the synchronization evaluation unit 114 determines and selects a predetermined filter 111p from among the plurality of filters 111a to 111e that corresponds to a symbol correlation value that has the largest level of correlation value calculated from the detected signal. By using the predetermined filter 111p, the received signal can be received in the best condition. In other words, the synchronization evaluation unit 114 selects a first correlation value that has the highest correlation value from among the plurality of correlation values, and selects a predetermined filter 111p from among the plurality of filters 111a to 111e that corresponds to the first correlation value. As a result, the band limiting unit 111 outputs a predetermined band-limited signal using the predetermined filter 111p.

[0033] Here, a description will be given of the operation of the synchronization detection unit 113. Specifically, a description will be given of an example of calculation of a symbol correlation value.

[0034] In this example, we assume that synchronous detection is performed for each symbol interval, and calculate the correlation value for the detected signal at each symbol interval using the synchronous symbol value. Each parameter is defined as follows: N: Number of samples in one symbol period M: Number of synchronization symbols (number of synchronization symbols) Rnm: Detected signal (detected data) for receiving the target for synchronous detection Sample position in one symbol n=1,2,…N Sync symbol position m=1,2,…M SYNCm: Sync symbol value at sync symbol position m Cn: Calculation result of correlation value for each symbol sample (C1, C2, ... CN) When each parameter is defined as above, the correlation value calculation result Cn is Cn=ΣRnm*SYNCm (n=1,2,…N, m=1,2,…M) This becomes: Here, the value of Cn increases, and when it reaches a predetermined threshold value or more, it is determined that this is the timing of the synchronization signal (the timing when synchronization is achieved).

[0035] FIG. 7 is a schematic diagram illustrating the detected waveform of the synchronization symbol. The horizontal axis in Fig. 7 represents time. Fig. 7 shows the detection result of the synchronization symbol. 7 shows an example of the detected waveform of the synchronization symbols (detected signal) for 10 symbols (-3, +1, -3, +3, -3, -3, +3, +3, -1, +3), where the detected signal has four-valued symbols. Figure 7 shows an example of a detected waveform when there is no frequency deviation and the synchronization symbol can be detected without any problems. The synchronization symbol is sometimes called a synchronization signal or SYNC data. The detected waveform is sometimes called a detected signal.

[0036] FIG. 8 is a schematic diagram illustrating the detected waveform of the synchronization symbol. The horizontal axis in Fig. 8 represents time. Fig. 8 shows the detection result of the synchronization symbol. FIG. 8 shows an example of a detected waveform when the synchronization symbol cannot be detected properly due to a frequency shift.

[0037] FIG. 9 is a schematic diagram illustrating the detected waveform of the synchronization symbol. The horizontal axis in Fig. 9 represents time. Fig. 9 shows the detection result of the synchronization symbol. Figure 9 shows an example of a detected waveform when a frequency deviation even greater than that shown in Figure 8 causes the frequency of the synchronization symbol (synchronization signal) to fall outside the filter band, degrading the detected waveform and making symbol detection (determination) impossible. The detected waveform deviates from the four-value symbol value.

[0038] As shown in Figures 7 to 9, the accuracy of detecting the symbol value of a synchronization symbol deteriorates as the center frequency of the synchronization symbol (synchronization signal) deviates from the center frequency of the filter. As shown in Figures 8 and 9, when the frequency deviation is large, the detected waveform of the synchronization symbol breaks down, so the correlation value remains small even when the synchronization timing is reached, making symbol detection (synchronization detection) impossible.

[0039] <Symbol detection status> When the correlation value is equal to or greater than a predetermined threshold, the synchronization detection device 11 transitions to a synchronization detection state, i.e., a symbol detection state (see FIG. 2). For example, when any one of the multiple correlation values ​​is equal to or greater than a predetermined threshold, the synchronization detection device 11 transitions to the symbol detection state. The operation of the synchronization detection device in the symbol detection state will now be described.

[0040] FIG. 10 is a block diagram illustrating a synchronization detection device according to an embodiment. FIG. 11 is a block diagram illustrating a synchronization detection device according to an embodiment. 10 and 11 show the sync detection device in the symbol detection state. 10 and 11 show a case where the synchronization evaluation unit 114 selects the +500 Hz offset filter 111b as the predetermined filter 111p.

[0041] As shown in Fig. 10, when the state transitions to the symbol detection state, the synchronization evaluation unit 114 selects a first correlation value, which is the highest correlation value, from among the multiple correlation values. The synchronization evaluation unit 114 also selects a predetermined filter 111p corresponding to the first correlation value from among the multiple filters 111a to 111e. As a result, the synchronization detection device 11 continues to receive the IF signal (received signal) using only the path of the predetermined filter 111p, the predetermined detector / demodulator 112p, and the predetermined synchronization detector 113p. The synchronization detection device 11 disconnects paths other than the selected path (paths of the filter, detector / demodulator, and synchronization detector).

[0042] 11, in the symbol detection state, a predetermined detector / demodulator 112p of the detector / demodulator 112 detects and demodulates a predetermined band-limited signal to output a predetermined detected signal. Also, in the symbol detection state, the symbol detector 116 of the synchronization detection device 11 detects a symbol from the predetermined detected signal.

[0043] In addition, in the symbol detection state, the synchronization evaluation unit 114 has a filter coefficient setting unit 114b and a frequency tracking unit 114a. The filter coefficient setting unit 114b sets the filter coefficient of the predetermined filter 111p to control the center frequency of the predetermined filter 111p. The frequency tracking unit 114a controls the center frequency of the predetermined filter 111p to adjust the correlation value of the predetermined filter 111p to the highest maximum correlation value.

[0044] In other words, the frequency tracking unit 114a detects a frequency deviation value and notifies the filter coefficient setting unit 114b in order to set the center frequency of the predetermined filter 111p to the center frequency it has determined. The center frequency of the filter can be controlled by complex coefficient transforming the frequency deviation value and setting a filter coefficient. The filter coefficient setting unit 114b performs complex coefficient transform based on the frequency deviation value to obtain the desired center frequency, calculates a filter coefficient, and updates the filter coefficient for the predetermined filter 111p. The filter coefficient setting unit is sometimes referred to as a complex coefficient transform unit. However, the calculation of the filter coefficient is not limited to complex coefficient transform, and other methods may be used.

[0045] Furthermore, a predetermined synchronization detector 113p in the synchronization detection unit 113 finds the value of the DC component (frequency deviation value) based on the value of the symbol at the time of synchronization detection (see FIGS. 8 and 9).

[0046] The synchronization detection device 11 also includes a frequency deviation elimination unit 115. The frequency deviation elimination unit 115 uses the value of the DC component (frequency deviation value) determined by the synchronization detection unit 113 to cut the value of the DC component from the predetermined detection signal, and outputs the resultant signal to the symbol detection unit 116 as a predetermined DC cut signal (predetermined frequency deviation correction signal).

[0047] The symbol detector 116 detects symbols from a predetermined DC-cut signal (a predetermined frequency deviation correction signal).

[0048] FIG. 12 is a flowchart illustrating the operation of the synchronization detection device according to the embodiment. FIG. 12 shows the operation flow in the standby state and the symbol detection state.

[0049] As shown in FIG. 12, the synchronization detector 113 obtains a correlation value of a synchronization symbol in the standby state (step S101).

[0050] If the correlation value is equal to or greater than the predetermined threshold value (step S102: Yes), the synchronization evaluation unit 114 transitions to a symbol detection state and selects a predetermined filter 111p corresponding to the first correlation value.

[0051] If the correlation value is less than the predetermined threshold (step S102: No), the synchronization evaluation unit 114 ends the symbol detection state. In this case, the synchronization evaluation unit 114 may return to the standby state. For example, the synchronization evaluation unit 114 enters the standby state when all of the correlation values ​​are less than the predetermined threshold.

[0052] In the symbol detection state, the synchronization detector 113 obtains the value of the DC component, that is, the frequency deviation value, based on the symbol value error between the detected signal and a predetermined synchronization signal (synchronization symbol pattern) (step S103).

[0053] The frequency deviation elimination unit 115 uses the frequency deviation value to cut (eliminate) the value of the DC component from the predetermined detected signal (step S104).

[0054] The filter coefficient setting unit 114b performs complex coefficient conversion based on the frequency deviation value, obtains filter coefficients, and sets the filter coefficients for the predetermined filter 111p (step S105).

[0055] By performing the operations from step S101 to step S105 and tracking the frequency deviation with high accuracy, the center frequency of the predetermined filter 111p can be made to track the center frequency of the IF signal.

[0056] <Effects> Even when the center frequency of an IF signal (received signal) is outside the band of one filter (when there is a frequency shift), the synchronization detection device 11 according to the embodiment arranges multiple filters with different center frequencies, waits for the IF signal, and selects the optimal filter. This reduces the time required to pull the frequency-shifted IF signal into the band of the filter.

[0057] As a result, it is possible to provide a synchronization detection device, a synchronization detection method, and a synchronization detection program that can quickly track the frequency deviation of the intermediate frequency (IF) after down-converting the radio frequency. Furthermore, according to the embodiments, it is possible to instantly detect the synchronization symbol.

[0058] Furthermore, according to the embodiment, the frequency shift of the IF signal (received signal) is tracked by setting a filter coefficient and controlling the center frequency of the filter, so there is no need to switch the frequency of the local signal (local oscillator), which simplifies the circuit configuration of the receiving system.

[0059] <Features> The features of the present invention will now be described below. The present invention relates to automatic frequency control processing during reception (demodulation) of a wireless communication device (synchronization detection device). In order to follow the shift in the center frequency of the IF signal, the system has a configuration in which multiple filters with slightly shifted center frequencies are arranged in parallel within the baseband. The center frequency of the filter is controlled by setting the filter coefficient, and the frequency deviation is tracked.

[0060] Note that some or all of the above processes may be executed by a computer program. The above-described program can be stored and provided to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic storage media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical storage media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)). The program may also be provided to a computer by various types of transitory computer-readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer-readable media can provide the program to a computer via wired communication paths such as electric wires and optical fibers, or via wireless communication paths.

[0061] The invention has been specifically described above based on an embodiment, but it goes without saying that the present invention is not limited to the above embodiment and can be modified in various ways without departing from the spirit of the invention. [Explanation of symbols]

[0062] 10...Wireless communication device 11...Synchronous detection device 11b...Baseband section 111...Bandwidth limiter 111a to 111e...filters 111p...prescribed filter 112...Detection and demodulation unit 112a to 112e... Detector demodulators 112p...prescribed detector demodulator 113...Synchronization detection unit 113a to 113e...Synchronous detectors 113p...predetermined synchronous detector 114...Synchronous evaluation unit 114a...frequency tracking unit 114b...Filter coefficient setting unit 115...Frequency deviation elimination unit 116...Symbol detection unit 116t...Digital modulation section 117a, 117b, 117t...Frequency mixing section 118...Bandwidth limiting section

Claims

1. A plurality of filters each having a different center frequency for an externally received signal are used to a band limiting unit that limits the band of a signal and outputs a plurality of band-limited signals; A demodulator that detects and demodulates each of the plurality of band-limited signals and outputs a plurality of detected signals. With Chobe, a synchronous detection unit that synchronously detects each of the plurality of detection signals and outputs a plurality of correlation values; A predetermined filter is selected from the plurality of filters based on the plurality of correlation values. a synchronization evaluation unit; Equipped with The synchronization evaluation unit is configured to set a center frequency of the filter based on the correlation value. a tracking unit and a filter coefficient setting unit, The synchronization evaluation unit sets the highest correlation value among the plurality of correlation values ​​as a first correlation value, When the predetermined filter corresponding to the first correlation value is selected from the number of the filters, The frequency tracking unit detects a frequency deviation value of the selected predetermined filter, and The filter coefficient setting unit updates the center frequency of the predetermined filter based on the frequency deviation value. New, The band limiting unit outputs a predetermined band-limited signal using the updated predetermined filter. do, Synchronous detection device.

2. The band limiting unit, the detection and demodulation unit, the synchronization detection unit, and the synchronization evaluation unit are If all of the plurality of correlation values ​​are less than a predetermined threshold, a standby state for repeating the synchronization detection is established. transition to the If any of the plurality of correlation values ​​is equal to or greater than the predetermined threshold, the predetermined filter is selected. transition to the symbol detection state, 2. The synchronization detection device according to claim 1.

3. A plurality of filters each having a different center frequency for an externally received signal are used to limiting the band of the signal to output a plurality of band-limited signals; detecting and demodulating each of the plurality of band-limited signals to output a plurality of detected signals; 、 synchronously detecting each of the plurality of detection signals and outputting a plurality of correlation values; A predetermined filter is selected from the plurality of filters based on the plurality of correlation values. And, The highest correlation value among the plurality of correlation values ​​is defined as a first correlation value, and When the predetermined filter corresponding to the first correlation value is selected, the selected predetermined and detecting a frequency deviation value of the filter, and determining a frequency deviation value of the predetermined filter based on the frequency deviation value. updating the center frequency; outputting a predetermined band-limited signal using the updated predetermined filter; A synchronous detection method comprising:

4. A plurality of filters each having a different center frequency for an externally received signal are used to limiting the band of the signal to output a plurality of band-limited signals; detecting and demodulating each of the plurality of band-limited signals to output a plurality of detected signals; 、 synchronously detecting each of the plurality of detection signals and outputting a plurality of correlation values; A predetermined filter is selected from the plurality of filters based on the plurality of correlation values. And, The highest correlation value among the plurality of correlation values ​​is defined as a first correlation value, and When the predetermined filter corresponding to the first correlation value is selected, the selected predetermined and detecting a frequency deviation value of the filter, and determining a frequency deviation value of the predetermined filter based on the frequency deviation value. updating the center frequency; outputting a predetermined band-limited signal using the updated predetermined filter; A synchronization detection program that causes a computer to execute the following.

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