JP3308910B2 - Synchronous holding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronization holding device in a communication device such as a portable telephone, and more particularly to a device for correcting a frame timing based on a value stored in a memory even when a UW pattern cannot be detected. It is composed.

[0002]

2. Description of the Related Art In a communication device such as a portable telephone, a synchronization maintaining device is extremely important. FIG. 5 is a block diagram showing the configuration of a conventional synchronization holding device. In a conventional synchronization holding device, a known symbol pattern (usually called a synchronization word or a unique word; hereinafter, referred to as a UW pattern: a unique word pattern) of a received signal 501 is detected, and a reference timer operated by a reference clock 502 is detected. Latch the value of 504. Based on this value, the time when the UW pattern was received is calculated
(508).

[0003] Then, a histogram of the UW pattern reception time is calculated (510), and the difference between the reference frame timing of the transmitting device and the reference frame timing of the receiving device is calculated (51).
2) Yes. If the reference frame timing of the receiving device is shifted backward from the reference frame timing of the transmitting device based on this histogram, the reference frame timing of the receiving device is corrected forward, and the reference frame timing of the receiving device is adjusted to the transmitting device. If the reference frame timing is shifted forward from the reference frame timing, the reference frame timing of the receiving device is corrected backward.

Actually, when correcting forward, the initial value of the reference timer is set to +1; when correcting backward, the initial value of the reference timer is set to -1, and the count value of the reference timer (the frame length of the receiving apparatus) is set. ) Is increased or decreased to synchronize the frame timing 514 of the receiving device with the frame timing of the transmitting device.

[0005]

However, in such a conventional synchronization holding device, the difference between the frame timing of the transmitting device and the frame timing of the receiving device is detected by always receiving the UW pattern, and the synchronization of the receiving device is detected. The frame timing is corrected.

In such a device configuration, it is difficult to maintain synchronization between the frame timing of the transmitting device and the frame timing of the receiving device when the UW pattern cannot be received for a long time due to a line disconnection or the like. There were challenges.

[0007]

According to the present invention, in a frame timing of a receiving apparatus, a time at which a UW pattern is to be detected in advance (when there is no difference between the frame timings of the transmitting apparatus and the receiving apparatus, the UW pattern is generated at the receiving apparatus). Is detected as a UW pattern detection reference value, a difference between this reference value and a value of a reference timer latched by detection of the UW pattern is calculated, and the frame timing is corrected based on the timing shift. At this time, by storing the calculated difference in the memory, even when the UW pattern cannot be detected, the frame timing is corrected based on the value stored in the memory (correction history information when the UW pattern can be detected). Therefore, even when the UW pattern cannot be received for a long time, the frame timing of the transmitting device and the receiving device can be maintained.

According to a first aspect of the present invention, there is provided a known pattern detecting means for detecting a known transmission pattern from a received signal, a reference timer operated by a reference clock,
A latch means for holding the value of the group <br/> quasi timer by the detection pulse from the known pattern detecting means, a timing difference calculation means for calculating a difference between the latched timer value and the timing reference value, the calculated timing A memory means for storing the difference, a selector means for selecting one of the data of the timing difference calculating means or the memory means by a detection presence / absence signal from the known pattern detecting means, and a timing difference selected by the selector means. A synchronization holding device comprising a correction unit for generating a correction signal and a frame timing generation unit for generating a frame timing corrected by the correction signal from the correction unit, wherein a UW pattern cannot be detected. Even in this case, the value stored in the memory means (supplementary when the UW pattern is detected) Since the history information) can be corrected frame timing on the basis of such an action can hold frame timing of the transmitter and the receiver even when UW pattern is such not be received for a long time.

According to a second aspect of the present invention, there is provided a communication terminal including the synchronization maintaining apparatus according to the first aspect, wherein the transmitting apparatus is used even when a UW pattern cannot be received for a long time. This has the effect of providing a communication terminal capable of holding the frame timing of the receiving device.

According to a third aspect of the present invention, there is provided a communication system including the synchronization maintaining apparatus according to the first aspect and the communication terminal according to the second aspect, wherein the UW pattern is provided for a long time. This has the effect of providing a communication system capable of maintaining the frame timing of the transmitting device and the receiving device even when reception is not possible.

According to a fourth aspect of the present invention, there is provided a known pattern detecting means for detecting a known transmission pattern from a received signal, a reference timer operated by a reference clock, and a detection pulse from the known pattern detecting means. said latch means for holding the value of the reference timer, the timing difference calculating means for calculating a difference between the latched timer value and the timing reference value, and averaging means for calculating an average value of the timing difference, the calculated timing by A memory means for storing an average value of the difference, a selector means for selecting one of the data of the timing difference calculating means or the memory means, based on a detection presence / absence signal from the known pattern detecting means; Correction means for generating a correction signal from a timing difference; and a correction means for correcting the correction signal from the correction means. A frame timing generating means for generating a frame timing, wherein the synchronization maintaining apparatus is capable of maintaining the frame timing of the transmitting apparatus and the receiving apparatus even when the UW pattern cannot be received for a long time. In addition, since the data stored in the memory means can be minimized by averaging the timing difference, the capacity of the memory means can be minimized and the device can be miniaturized.

According to a fifth aspect of the present invention, there is provided a communication terminal including the synchronization maintaining device according to the fourth aspect, wherein the transmission terminal is used even when a UW pattern cannot be received for a long time. Since the frame timing of the receiving device can be retained and the data stored in the memory means can be minimized by averaging the timing differences, the capacity of the memory means can be minimized and the device can be downsized. It has the effect of providing a communication terminal that can.

According to a sixth aspect of the present invention, there is provided a communication system including the synchronization maintaining apparatus according to the fourth aspect and the communication terminal according to the fifth aspect, wherein the UW pattern is provided for a long time. Even when reception is not possible, the frame timing of the transmitting device and the receiving device can be retained, and the data stored in the memory means can be minimized by averaging the timing difference, so that the capacity of the memory means is minimized. This has the effect of providing a communication system capable of realizing miniaturization of the apparatus while suppressing the size of the apparatus.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a synchronization holding device according to a first embodiment of the present invention. In FIG. 1, when the UW pattern is detected from the received signal 101, the synchronization holding device of the first embodiment
A UW pattern detection unit 103 that generates a W detection pulse 105 and generates a UW detection presence / absence signal 113, a reference timer 104 that is counted by a reference clock 102 and outputs a counter value 106, and a reference timer 104 that uses the UW detection pulse 105.
A latch unit 107 for taking in the counter value 106 of the receiving device, a timing difference calculating unit 110 for calculating a frame timing difference 111 between the receiving device and the transmitting device from the latched counter value 108 and the timing reference value 109, and a timing difference 111 are stored. A memory unit 112, a selector 114 for switching between a timing difference from the timing difference calculation unit 110 and a timing difference from the memory 112 by a UW detection presence / absence signal 113, a reference clock 102
And a correction unit 116 that outputs a correction signal 117 based on a timing difference 115 output from the selector 114 and a reference clock 102.
And a frame timing generation unit 118 that generates a frame timing signal 119 and a frame interrupt signal 120 based on the correction signal 117.

The operation of the synchronization holding device according to the first embodiment will be described with reference to FIG. The UW signal transmitted by the transmitting device is a reference timer value X in the transmitting device.
(This value is a timing reference value on the receiving device side). In the receiving apparatus, UW pattern detection section 103 detects a UW pattern from reception signal 101 including the UW signal, and outputs UW detection pulse 105 and UW detection presence / absence signal 113.
Occurs.

In response to the UW detection pulse 105, the reference timer value (x + α _n-1 ) in the receiving apparatus is taken into the latch unit 107 as the UW detection time. Next, in the timing difference calculating section 110, the latched counter value (x + α _n-1 )
(108) and the timing reference value x (109), the timing difference (α
_n-1 ) Calculate (111).

Thereafter, in the selector 114, the timing difference (α _n-1 ) selected by the UW detection presence / absence signal 113
(115) and the calculated timing difference (α
_n-1 ) (111) is stored in the memory unit 112 as correction history information. Then, at the timing when the frame interrupt signal 120 is generated, the correction unit 116 corrects the a synchronization deviation between transmission and reception (α _n-1) by using the calculated timing difference _{(α n-1) (115} ) When the calculated value is plus, the frame timing is corrected backward. If the calculated value is negative, the frame timing is corrected forward.

Based on the correction signal 117, the frame timing is corrected backward or forward from the frame timing generator 118,
A frame timing signal 119 synchronized with the transmitting apparatus and a frame interrupt signal 120 for notifying the timing of performing the correction processing are generated.

In the state where the UW pattern is detected as described above, the timing difference 11 actually used in the correction processing is used.
1 is stored in the memory as correction history information. At this time, the memory unit 112 uses two storage areas for the correction history information, and sequentially updates the correction history information as follows: storage area 1 → storage area 2 → storage area 1 → storage area 2 → storage area 1. Configuration.

From this, if the line between the transmission and the reception becomes abnormal while the storage area 2 of the correction history information is being updated (when the UW pattern is not detected), the UW pattern detector 10
The UW detection presence / absence signal 113 output from 3 indicates a non-detection state, and the selector 114 switches to the timing difference output of the storage area 1 on the memory side.

As a result, the correction history information is sequentially and cyclically read from the memory of the storage area 1, and even when the UW pattern is not detected, it is possible to perform correction of a value very close to the actual synchronization deviation. The synchronization state between the transmitting and receiving apparatuses can be maintained.

After the line status is restored, the correction history information is sequentially updated from the head of the storage area 2 to the storage area 2 → the storage area 1
→ Storage area 2 → Storage area 1 ... The correction history information is updated to prepare for a line abnormal state.

By providing the synchronization holding device in the communication terminal, it is possible to provide a communication terminal capable of holding the frame timing of the transmitting device and the receiving device even when the UW pattern cannot be received for a long time. . Further, by constructing a communication system by combining the synchronization holding device and the communication terminal, a communication system capable of holding the frame timing of the transmitting device and the receiving device even when the UW pattern cannot be received for a long time. Can be provided.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration of a synchronization holding device according to the embodiment. In FIG. 3, when the UW pattern is detected from the received signal 301, the synchronization holding device according to the second embodiment
A UW pattern detection unit 303 that generates a W detection pulse 305 and generates a UW detection presence / absence signal 313, a reference timer 304 that counts by a reference clock 302 and outputs a counter value 306, and a reference timer 304 that outputs a counter value 306.
A latch 307 that captures the counter value 306 of the receiving device, a timing difference calculating unit 310 that calculates a frame timing difference 311 between the receiving device and the transmitting device from the latched counter value 308 and the timing reference value 309, and a timing difference initial value 323. An averaging processing unit 321 for inputting and averaging the timing difference 311 and updating the average value when UW detection is present, a memory unit 312 for storing the averaged timing difference 322, and a UW detection presence / absence signal 313 A selector 314 for switching between the timing difference from the timing difference calculator 310 and the averaged timing difference 322 from the memory 312, and outputs a correction signal 317 based on the reference clock 302 and the timing difference 315 output from the selector 314. And a frame timing for generating a frame timing signal 319 and a frame interrupt signal 320 based on the reference clock 302 and the correction signal 317. And a generating unit 318 Prefecture.

The operation of the synchronization holding device according to the second embodiment will be described with reference to FIG. The UW signal transmitted by the transmitting device is a reference timer value X in the transmitting device.
(This value is a timing reference value on the receiving device side). In the receiving apparatus, UW pattern detection section 303 detects a UW pattern from reception signal 301 including the UW signal, and outputs UW detection pulse 305 and UW detection presence / absence signal 313.
Occurs.

Then, in response to the UW detection pulse 305, the reference timer value (x + α ₁ ) in the receiving device is taken into the latch unit 307 as the UW detection time. Next, in the timing difference calculation section 310, the latched counter value (x + α ₁ ) (30
8) and the timing reference value x (309), the timing difference α ₁ (31
1) is calculated.

Thereafter, in the selector 314, the timing difference α ₁ (315) selected by the UW detection presence / absence signal 313
And the calculated timing difference α ₁ (311)
And the average value of the timing difference initial value α ₀ (323). This is used as the average correction information when the line is in the normal state in the memory section.
Store in 312.

Then, at the timing when the frame interrupt signal 320 is generated, the correction unit 316 uses the calculated timing difference α ₁ (315) to correct α ₁ , which is the synchronization deviation between transmission and reception, by using a correction signal 317. When the calculated value is plus, the frame timing is corrected backward. If the calculated value is negative, the frame timing is corrected forward.

Based on the correction signal 317, the frame timing is corrected backward or forward from the frame timing generation unit 318.
A frame timing signal 319 synchronized with the transmitting apparatus and a frame interrupt signal 320 for notifying the timing of performing the correction processing are generated.

In the state where the UW pattern is detected as described above, the timing difference 31 actually used for the correction processing is used.
1 is stored in the memory as average correction information as needed. As a method of the averaging process, the timing difference initial value is used only at the initial stage, and thereafter, the average value between the previous average correction information and the current timing difference is calculated. The average correction information is configured to be updated as needed.

From this, when the line between transmission and reception becomes abnormal (when the UW pattern is not detected), the UW detection presence / absence signal 313 output from the UW pattern detection unit 303 is in the non-detection state. And the selector 314 switches to the averaged timing difference output on the memory side.

As a result, the average correction information is read from the memory, and even when the UW pattern is not detected, the average value can be corrected for the actual synchronization deviation. State can be maintained.

After the line condition is restored, the average value between the previous average correction information and the current timing difference is calculated again, the average correction information is updated to be stored in the memory, and a line abnormal condition is prepared. .

By providing the synchronization holding device in the communication terminal, it is possible to provide a communication terminal capable of holding the frame timing of the transmitting device and the receiving device even when the UW pattern cannot be received for a long time. . Further, by constructing a communication system by combining the synchronization holding device and the communication terminal, a communication system capable of holding the frame timing of the transmitting device and the receiving device even when the UW pattern cannot be received for a long time. Can be provided.

[0036]

As is clear from the description of the above embodiment, the present invention has the following features. Even if the communication line disconnection (when the UW pattern is not detected) continues for a long time, the timing correction history information can be read from the memory and the timing can be corrected, so that the synchronization between the transmitting device and the receiving device can be realized. By averaging the timing difference stored in the memory unit, the data to be stored can be minimized, so that the capacity of the memory unit can be minimized and the device can be downsized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a synchronization holding device according to a first embodiment of the present invention;

FIG. 2 is a timing chart for explaining the operation of the synchronization holding device according to the first embodiment of the present invention;

FIG. 3 is a block diagram showing a configuration of a synchronization holding device according to a second embodiment of the present invention;

FIG. 4 is a timing chart for explaining the operation of the synchronization holding device according to the second embodiment of the present invention;

FIG. 5 is a block diagram showing a configuration of a conventional synchronization holding device.

[Explanation of symbols]

 101, 301, 501 Received signal 102, 302, 502 Reference clock 103, 303, 503 UW pattern detection unit 104, 304, 504 Reference timer 105, 305, 505 UW pattern detection pulse 106, 306, 506 Reference value of reference timer 107 , 307, 507 Latch section 108, 308, 508 Latched reference timer count value 109, 309 Timing reference value 110, 310 Timing difference calculation section 111, 311 Timing difference 112, 312 Memory section 113, 313 UW detection available / not available 114 , 314 Selector 115, 315 Selected timing difference 116, 316 Correction unit 117, 317 Correction signal 118, 318, 513 Frame timing generation unit 119, 319, 514 Frame timing 120, 320 Frame interrupt 321 Averaging unit 322 Averaging Timing difference 323 Timing difference initial value 509 UW pattern detection time histogram calculation unit 510 Histogram calculation result 511 Timing correction value detection unit 512 Correction value detection result

Claims (6)

(57) [Claims] From 1. A received signal and a known pattern detecting means for detecting a known transmission pattern, a reference timer that operates by reference clock, the detection pulse from the known pattern detecting means for holding the value of the reference timer Latch means; timing difference calculating means for calculating a difference between a latched timer value and a timing reference value; memory means for storing the calculated timing difference; and a timing presence / absence signal from the known pattern detection means. Selector means for selecting one of the data of the calculating means or the memory means, a correcting means for generating a correction signal from a timing difference selected by the selector means, and a frame timing corrected by the correction signal from the correcting means. Synchronizing characterized by comprising frame timing generating means for generating Holding device. 2. A communication terminal comprising the synchronization maintaining device according to claim 1. 3. A communication system comprising the synchronization maintaining device according to claim 1 and the communication terminal according to claim 2. From wherein the received signal and a known pattern detecting means for detecting a known transmission pattern, a reference timer that operates by reference clock, the detection pulse from the known pattern detecting means for holding the value of the reference timer Latch means, timing difference calculating means for calculating a difference between the latched timer value and the timing reference value, averaging processing means for calculating the average value of the timing difference, and memory means for storing the calculated average value of the timing difference Selector means for selecting one of the data of the timing difference calculating means or the memory means in accordance with a detection presence / absence signal from the known pattern detecting means; and correction for generating a correction signal from the timing difference selected by the selector means Means for generating a frame timing corrected by a correction signal from the correction means. A synchronization holding device comprising: a frame timing generation unit. 5. A communication terminal comprising the synchronization maintaining device according to claim 4. 6. A communication system comprising the synchronization maintaining device according to claim 4 and the communication terminal according to claim 5.