JP2806151B2 - Frame correlation 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 frame correlation device used for processing a received signal of a digital communication device.

[0002]

2. Description of the Related Art In recent years, in the field of communications, especially land mobile communications, a time division multiplex digital communication system has been adopted, and detection of a slot, which is a signal group time-divided from a received signal, is performed by a so-called correlated signal of "1". Is carried out by a frame correlation apparatus for obtaining a frame correlation.

Next, an example of the frame correlation apparatus will be described. FIG. 2 shows the configuration of a conventional frame correlation device. In FIG. 2, reference numeral 101 denotes a correlation unit which generates a correlation output signal by correlating an input correlated signal with a correlation signal which is the other input, and is constituted by an AND circuit. Reference numeral 102 denotes a shift register that generates a correlation signal to be used as the other input of the correlation unit 101 by using a correlation output signal from the correlation unit 101 and a clock signal synchronized with the correlated signal, and can store data for one frame. It has a number of stages (for example, N stages).

[0004] Next, the operation of this conventional example will be described. First, the shift register 102 is initialized, and all data “1” is stored in a storage register (not shown). The logical product of the correlated signal A of one frame and the output of the shift register 102, that is, the correlation signal B of all "1" is obtained, and the same correlation output signal Y as the correlated signal is input to the shift register 102. When the correlated signal A is input in the next frame, the correlation signal B in the previous frame is input.
(= A) and a correlation output signal Y (B · A)
Is obtained. That is, when A = 1 and B = 1, the output Y of the correlation unit 101 becomes “1”, indicating that the correlation has been obtained.

As described above, the correlation with the correlation output signal obtained one frame before is always obtained. The shift register 102 is shifted by a shift clock that is a clock synchronized with the correlated signal, and the output of the shift register 102, that is, the correlation signal and the correlated signal are
Since the relative positions in the frame become equal, the frame correlation can be obtained.

[0006]

However, in the above-mentioned conventional frame correlation apparatus, it is necessary to store a correlation signal for one frame in the shift register without fail.
When the length of one frame is long or when the number of data in one frame is large, there is a problem that the scale of the apparatus increases.

In particular, when over-sampling of a correlated signal, there is a problem that the device scale of the shift register is extremely increased, making it difficult to implement an LSI, and furthermore, the power consumption is increased, which is not practical. Was.

An object of the present invention is to solve such a problem in the prior art, and an object of the present invention is to provide an excellent frame correlation apparatus capable of reducing the apparatus scale even when one frame time length is long.

[0009]

In order to achieve the above object, a frame correlation apparatus according to the present invention controls a correlation means for obtaining a frame correlation of a correlated signal having one frame as a unit of a signal format, and controlling the correlation means. Storage means for storing the relative time within one frame, storage means control means for controlling the storage means, and time measurement means for measuring the time of one frame, and directly stores the correlation output signal. This is a configuration in which the relative time within one frame that has a correlation is stored without performing the correlation.

[0010] The number of data stored in the storage means is determined by the sum of the probability of occurrence of data having an error correlation per frame in the correlated signal and the number of data having a correct correlation per frame. Also, by adjusting the number of data stored in the storage means, the time required for obtaining a true frame correlation output and the scale required for obtaining a frame correlation are adjusted.

[0011]

The frame correlation apparatus of the present invention stores the occurrence time (relative time within one frame) only when there is a correlation without directly storing the correlation signal for one frame. In the frame time, the correlation is performed based only on the stored correlation occurrence time, all the correlation output signal data for one frame time are not stored, and the device scale of the storage device for storing the correlation output signal is reduced. You.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a frame correlation apparatus according to the present invention.

FIG. 1 shows the configuration of the embodiment. In FIG. 1, reference numeral 1 denotes a correlator for correlating an input correlated signal A (logical value "0" or logical value "1") with a correlated signal Z input from the other. Corresponding). Reference numeral 2 denotes a memory control unit (corresponding to a storage unit control unit in claims) that controls data writing to a memory based on a correlation output signal from the correlation unit 1.
Reference numeral 3 denotes a counter (corresponding to a time measuring means in the claims) which counts one frame time length in synchronization with the clock signal and outputs a count value D. Reference numeral 4 denotes a memory for storing a count value D (relative time within one frame) of a counter in accordance with a control signal from the memory control unit 2 and outputting stored contents as necessary (corresponding to a storage means in the claims). ). Reference numeral 5 denotes a correlation control unit (corresponding to a correlation control unit in the claims) that compares the count value D of the counter 3 with the content stored in the memory 4 and outputs the comparison result to the correlation unit 1.

Next, the operation of the configuration of this embodiment will be described. First, the counter 3 always counts the clock signal B equal to the data rate (frequency) of the correlated signal A, and generates one frame time length (the count value D of the counter 3 indicates a relative time within a frame). Memory 4
Is initialized, and no data is stored.

When no data is stored in the memory 4, the correlation control unit 5 sets the correlation control signal B to "1". When data is stored in the memory 4, the stored data E is stored in the memory 4. Compare the count value D of the counter 3 and
When they match, the correlation control signal B is set to "1". When they do not match, the correlation control signal B is set to "0".

The correlated signal A is correlated with the output correlation control signal C of the correlation control section 5 in the correlation section 1 and is input to the memory control section 2 as a correlation signal Z.

When the correlation signal Z is "1", the memory controller 2 determines that the counter value of the counter 3 at that time is not stored in the memory 4 unless the counter value D of the counter 3 at that time is stored in the memory 4. D is stored in the memory 4. Conversely, when the correlation signal Z is “0”, if the same value as the counter value D of the counter 3 at that time is stored in the memory 4, the same value is deleted from the memory 4.

By repeating this operation for several frames, the correlation output Z becomes "1" only at the time when the correlated signal A becomes "1" at the same relative time for each frame, and the frame correlation can be obtained. it can.

The maximum number of data that can be stored in the memory 4 can be determined by the probability that "1" is erroneously output during one frame time in the correlated signal A.

For example, when the probability is m, the maximum number n of data that can be stored in the memory 4 is expressed by the following equation (1).

N = k × m + h (1) k: the number of data of one frame included in the correlated signal A, h:
Number of data to be output "1" in one correlated signal A during one frame time If the number of data that can be stored in the memory 4 is made smaller than n, more correlated signals A are obtained simply to obtain the true correlation output Z. Only the number of data is required. That is,
A long time for frame correlation is required.

As described above, in the above embodiment, the hardware (apparatus) scale can be reduced by making the number of data that can be stored in the memory 4 smaller than the number of one frame data included in the correlated signal A.

[0023]

As is apparent from the above description, the frame correlation apparatus according to the present invention does not directly store the correlation signal for one frame but directly generates the time of occurrence (the relative time within one frame). Target time), and in the next frame time, the correlation is calculated based only on the stored correlation occurrence time, so that all the correlation output signal data for one frame time can be prevented from being stored, This has the effect that the scale of the storage device for storing the correlation output signal can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a frame correlation apparatus according to the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional frame correlation apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Correlation part 2 Memory control part 3 Counter 4 Memory 5 Correlation control part A Correlated signal B Correlation control signal C Output correlation control signal D Count value E Storage data Z Correlation signal

Claims (3)

(57) [Claims] 1. Correlation means for obtaining a frame correlation of a correlated signal using one frame as a unit of a signal format, correlation control means for controlling the correlation means, and storage means for storing a relative time within one frame. A storage unit control means for controlling the storage means, and a time measuring means for measuring the time of the one frame, and storing a relative time within the one frame having a correlation without directly storing a correlation output signal. A frame correlation apparatus characterized by the above-mentioned. 2. The number of data stored in the storage means is determined by the sum of the probability of occurrence of data having an error correlation per frame and the number of data having a correct correlation per frame in a correlated signal. The frame correlation apparatus according to claim 1, wherein 3. The method according to claim 1, wherein the time required for obtaining a true frame correlation output and the scale required for obtaining a frame correlation are adjusted by adjusting the number of data stored in the storage means. The frame correlation apparatus according to claim 1, wherein