JPH0779219A - Synchronous word detection system - Google Patents

Abstract

PURPOSE:To provide a synchronous word detection system capable of surely detecting a synchronous word even when the same data as the synchronous word are present in the data in reception burst signals and quickly establishing synchronization. CONSTITUTION:At the time of detecting the synchronous word, a channel identification code placed behind the synchronous word is monitored by a channel identification code comparing and judging device 4. When the channel identification code placed behind the synchronous word is detected and judged in the channel identification code comparing and judging device 4 following the detection of the synchronous word by a synchronous word comparing and judging device 2, a synchronous word detection signal is outputted as the detection of the synchronous word.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device for detecting a synchronization word transmitted from a transmitting side and performing synchronous reception,
In particular, the present invention relates to a sync word detection method in which a sync word is detected by both a sync word and a channel identification code following this sync word.

[0002]

2. Description of the Related Art Generally, for example, in digital wireless communication multiplexed on a time axis, in order to extract only information of a desired line from a received signal, frame synchronization is performed to identify a frame position at a receiving side. It needs to be processed. In this frame synchronization processing, a synchronization word (unique word) of a specific bit is placed and transmitted from the transmission side at a specific position in the frame, and the reception side detects this synchronization word and transmits / receives between the transmission side and the reception side. This is performed by shifting to synchronous reception that establishes timing.

FIG. 2 is a timing chart showing a general burst signal timing when wireless communication is performed between four master units and four slave units using TDMA / TDD4 multiplexing. In this case, each slave unit receives the burst signal sent from the four master units at a constant cycle, and detects the synchronization word UW included in this burst signal to detect between the master unit and the slave units. Establish synchronization. Here, as shown in FIG. 2, the burst signals sent from the four masters at a constant cycle include burst signals from the four masters, that is, a burst signal of master A and a burst signal of master B. , A burst signal of master device C and a burst signal of master device D are included.

The burst signal of master device A, the burst signal of master device B, the burst signal of master device C, and the burst signal of master device D are preamble data PR and synchronization word U, respectively.
W, a channel identification code CI, and data DATA are included. For example, the slave unit A detects the synchronization word UW included in the burst signal of the master unit A, and thereby the master unit A and the slave unit A are detected.
Need to establish synchronization with. Here, the burst signal of the master unit A can be identified by detecting the channel identification code CI included in the burst signal of the master unit A. That is, the burst signal of the master unit A, the burst signal of the master unit B, the burst signal of the master unit C, and the burst signal of the master unit D include different channel identification codes CI, for example, the slave unit A is the master unit. By detecting the channel identification code CI included in the A burst signal, the burst signal of the master A is identified.

Conventionally, in this type of communication apparatus, a sync word detecting circuit for detecting a sync word receives serial received data and sequentially outputs parallel received data as parallel data of a bit number corresponding to the sync word, as shown in FIG. A serial / parallel converter 1 for converting and outputting to a synchronous word, a synchronous word register 3 storing a synchronous word in advance, parallel data output from the serial / parallel converter 1 and a synchronous word stored in the synchronous word register 3. And a sync word comparison / determination unit 2 which outputs a sync word detection signal when the two match. The sync word detection signal output from the sync word comparison / determination unit 2 is applied to a sync signal generation circuit (not shown), and the sync signal generation circuit forms a sync signal based on this sync word detection signal. Synchronization is established between the master unit and the slave unit and a synchronous communication state is entered. Then, the slave that has established this synchronization transmits a burst signal to the master side at a constant cycle. The burst signals transmitted from the slave unit are shown in FIG. 2 as a burst signal of slave unit A, a burst signal of slave unit B, a burst signal of slave unit C, and a burst signal of slave unit D.

However, in such a conventional sync word detecting method, the sync word U is provided at a position other than the sync word location of the desired channel of the received data received by the slave.
If the same data as W exists, this data may be erroneously recognized as the synchronization word UW.

That is, when the slave A normally detects the sync word UW in the burst signal of the master A, the sync word comparison signal shown in FIG. As a result, as shown in FIG. 2, the slave unit A shifts from the asynchronous mode to the synchronous mode, and the synchronous signal generation circuit (not shown) goes low for a predetermined time, that is, after a time t from the time when the synchronous word detection signal is output. A sync signal that rises from level to high level is formed.

However, for example, when the same data as the synchronization word UW exists in the data DATA in the burst signal of the master unit A, this data is erroneously recognized as the synchronization word UW, and at this point, the data shown in FIG. Sync word comparison / determination device 2 shown in
A sync word detection signal is output from the sync signal generation circuit, and a sync signal generation circuit (not shown) forms a sync signal that rises from a low level to a high level for a predetermined time after the output of the sync word detection signal, that is, a normal synchronization. Cannot be established.

Further, when establishing the initial synchronization, it is necessary to detect the synchronization word UW of the burst signal having the predetermined channel identification code CI, but in the circuit shown in FIG. If the word is detected but the channel identification code CI is different than desired,
It is necessary to detect the synchronization word UW again and establish synchronization.

[0010]

As described above, in the conventional sync word detection method, when the same data as the sync word exists in the data in the burst signal from the master unit, this data is There is a case that the synchronization word is erroneously recognized and normal synchronization cannot be established.If the channel identification code is different from the desired one even if the synchronization word is detected normally, the synchronization word is detected again and the synchronization is established. There is an inconvenience that it is necessary to perform.

Therefore, according to the present invention, even if the same data as the sync word exists in the data in the received burst signal, the sync word can be surely detected and the synchronization can be established quickly. It is an object of the present invention to provide a synchronous word detection method that enables the above.

[0012]

In order to achieve the above object, the present invention provides a synchronization word detecting method for a communication device which detects a synchronization word transmitted from a transmitting side to perform synchronous reception. When the channel identification code following the sync word is detected subsequent to the detection, the sync word detection signal is output as the detection of the sync word.

[0013]

According to the present invention, when the sync word is detected, the channel identification code after the sync word is monitored, and when the sync word is detected and then the channel identification code after the sync word is detected. Then, a sync word detection signal is output to detect the sync word.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sync word detecting system of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of a synchronous word detecting circuit constructed by adopting the synchronous word detecting system of the present invention. In addition, in FIG.
The parts having the same functions as those of the conventional circuit shown in FIG. In FIG. 1, the sync word detection circuit of this embodiment comprises a serial / parallel converter 1, a sync word comparison / determination unit 2, a sync word register 3, and a channel identification code comparison / determination unit 4. Here, the serial / parallel converter 1 receives the serial reception data from the master unit (not shown), converts the serial reception data into parallel data having the number of bits corresponding to the synchronization word, and outputs the parallel data. The sync word register 3 stores a sync word in advance and outputs the sync word as parallel data.

The sync word comparison / determination unit 2 compares the parallel data of the number of bits corresponding to the sync word output from the serial / parallel converter 1 with the parallel data corresponding to the sync word output from the sync word register 3. Then, the detection determination of the synchronization word is performed.

The channel identification code comparison / determination unit 4 inputs the signal indicating the determination result output from the synchronization word comparison / determination unit 2, and operates when the signal indicating the determination result is a signal indicating the detection of the synchronization word. Then, the channel identification code CI appearing subsequent to the sync word in the received data from the master unit is compared and determined.

That is, a desired channel identification code CI is set in advance in the channel identification code comparison / decision unit 4, and when it becomes operable by the output of the synchronization word comparison / decision unit 2, this is received data from the master unit. The channel identification code CI that appears after the synchronization word is input, and the channel identification code CI input from this received data is compared with the preset desired channel identification code CI.
Then, as a result of this comparison, if the channel identification code CI input from the received data matches the preset desired channel identification code CI, a sync word detection signal is output. The sync word detection signal output from the channel identification code comparison / determination unit 4 is applied to a sync signal generation circuit (not shown), and the sync signal generation circuit forms a sync signal based on this sync word detection signal. Synchronization is established between the master unit and the slave unit and a synchronous communication state is entered. Then, the slave that has established this synchronization transmits a burst signal to the master side at a constant cycle.

As described above, according to this embodiment, the channel identification code received after the synchronization word is detected by the synchronization word comparison / judgment unit 2 is changed to the preset desired channel identification code. Since the channel identification code comparison / determination unit 4 determines whether or not they coincide with each other, and when the coincidence is confirmed, the channel identification code comparison / determination unit 4 outputs the synchronization word detection signal.
Even if the same data as the sync word exists in the data other than the sync burst signal, the sync word can be surely detected.

Further, since the channel identification code is confirmed together with the synchronization word, it is not necessary to detect the synchronization word again when the channel identification code is different from the desired one, and the asynchronous communication state is shifted to the synchronization state. It is possible to drastically reduce the time until the power is turned on and the time from the power-on to the communication is also drastically shortened.

[0021]

As described above, according to the present invention, when the sync word is detected, the channel identification code following the sync word is monitored, and after the sync word is detected, the sync word is postfixed to the sync word. When a channel identification code is detected, a sync word detection signal is output as a sync word detection.Therefore, even if the same data as the sync word exists in the data other than the sync burst signal, the sync word detection signal can be reliably executed. Can detect sync words, and
Since it is not necessary to detect the sync word again when the channel identification code is different from the desired one, the time from the asynchronous communication state to the synchronous state can be greatly shortened, and the communication from power-on to communication can be shortened. It also has the effect of significantly reducing the time required to move to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a sync word detection circuit configured by adopting the sync word detection system of the present invention.

FIG. 2 is a timing chart showing a general burst signal timing when wireless communication is performed between four master units and four slave units using TDMA / TDD4 multiplexing.

FIG. 3 is a block diagram showing a conventional sync word detection circuit.

[Explanation of symbols]

 1 Serial / parallel converter 2 Synchronous word register 3 Synchronous word comparison / determination device 4 Channel identification code comparison / determination device

Claims (1)

[Claims] 1. A synchronization word detecting method for a communication device for detecting a synchronization word transmitted from a transmitting side to perform synchronous reception, comprising: detecting a synchronization word; and subsequently detecting a channel identification code after the synchronization word. When detected, a sync word detection method that outputs a sync word detection signal as detection of the sync word.