JPH07101874B2 - Modulator / demodulator - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a modulator / demodulator (MODEM) that performs mutual conversion between a digital signal from a data terminal and an analog transmission signal to a transmission line.

[Prior art]

FIG. 3 is a block diagram showing a conventional modulator / demodulator. In the figure, 1 is a data terminal such as a personal computer or a host computer, and 2 is a wireless device that forms a transmission line by performing wireless communication with a partner station. Reference numeral 3 denotes a modulation / demodulation device for performing mutual conversion between a digital signal that can be handled by the data terminal 1 and an analog transmission signal such as a minimum phase shift keying (hereinafter referred to as MSK) signal, which is suitable for communication by the wireless device 2. Is. 4 is this modem 3
The digital signal from the data terminal 1 is MSK
A modulator 5 having a function of adding an error correction code to a signal to be transmitted to the wireless device 2 is also in the modulator / demodulator 3 and converts the MSK signal received by the wireless device 2 into a digital signal. It is a demodulation unit having an error correction function by the error correction code sent to the data terminal 1. Next, the operation will be described. The data sent from the data terminal 1 to the partner station is sent to the modulator / demodulator 3 by digital signals of "1" and "0". The modulator / demodulator 3 inputs the data by the digital signal to the modulator 4, and the modulator 4 converts it into an MSK signal corresponding to “1” and “0” according to the control of the data terminal 1 and transmits it to the radio device 2. input. When the wireless device 2 receives the data converted into the MSK signal suitable for this communication, it puts it on the radio wave and transmits it to the partner station. Further, the data by the MSK signal transmitted on the radio wave from the partner station by the same procedure as the above-mentioned procedure is received by the wireless device 2, sent to the modulation / demodulation device 3, and input to the demodulation unit 5. . The demodulation unit 5 converts the data of the MSK signal into digital signals corresponding to “1” and “0” and sends the digital signal to the data terminal 1. The data terminal 1 which has received the data from the partner station by the digital signal from the modulation / demodulation device 3 executes predetermined data processing using the data terminal 1.

[Problems to be Solved by the Invention]

Since the conventional modulator / demodulator is configured as described above,
The digital signal from the data terminal 1 is converted into an MSK signal and sent to the wireless device 2, and the MSK signal received by the wireless device 2 is only converted into a digital signal and sent to the data terminal, which is formed by the wireless device 2. If the transmission line is cut in the middle, clear the data sent up to that point,
All the data has to be retransmitted again, and the data terminal 1 needs to control the modulator / demodulator 3 at the time of data transmission / reception, and during that time, other processing work cannot be executed, Data terminal 1 to 3
There was a problem such as not being able to receive data when is not connected. The present invention has been made to solve the above-mentioned problems. Even if the transmission line is cut off or there is an error in part of the data, the data sent up to that point is considered to be valid. In addition to sending only the missing data, the data terminal can perform other processing work even when sending and receiving data, and receiving data from the partner station even when the data terminal is not connected It is an object of the present invention to obtain a modulator / demodulator capable of

[Means for Solving the Problems]

A modulation / demodulation apparatus according to the present invention divides data from a data terminal into fixed intervals, adds redundant bits for error detection or correction to each of them, and outputs the data as packet data. A block of data is created by adding a plurality of pieces of information to a modulator such as a transmitter station number and a receiver station number, which is necessary for communication between modulation / demodulation devices, and generating block data. From the data block converted into a digital signal in, the data receiving unit that takes in the receiving station number that matches the station number of its own station, and the error detection or correction of each packet data of the taken data block, A decoding unit that performs the redundant bits added to it,
A data storage unit for organizing and accumulating the data from the decoding unit is provided until all the data to the data terminal is collected.

[Work]

In the modulation / demodulation device according to the present invention, the encoding unit divides the data sent from the data terminal to the partner station into fixed intervals,
Packet data is generated by adding redundant bits for error detection or correction to each of them and sent to the data block forming unit. In the data block forming unit, a plurality of this packet data are collected, and the transmission station number and the receiving station are added to the packet data. While generating a data block to which information necessary for communication between the modulation and demodulation devices such as numbers is sent to the modulation unit, the receiving station number of the own station is selected from the data blocks converted into digital signals by the demodulation unit. The data receiving unit captures the one that matches the station number, and the decoding unit detects or corrects the error based on the redundant bit added to each packet data of the captured data block, and the packet with no error. During data transmission, data is sent to the data storage unit, and data is stored in the data storage unit until the data to the data terminal is completed and stored. Even if the transmission line is cut off in the middle or there is an error in part of the data, the data accumulated up to that point in the data storage section will remain valid and only the missing data will need to be retransmitted. In addition, by eliminating the need for the data terminal to control the modulator / demodulator at the time of data transmission / reception, enabling the execution of other processing operations during that time, and storing the received data in the data storage unit, Enable to receive data from the partner station even if the data terminal is not connected.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a data terminal, 2 is a wireless device, 3 is a modulator / demodulator, 4 is a modulator, 5 is a demodulator, and FIG. 3 is the same as or equivalent to those of the prior art with the same reference numerals. Therefore, detailed description is omitted. Reference numeral 6 is a data receiving unit that receives data sent from the data terminal 1 and accumulates data for one partner station, and 7 divides the data received and accumulated by the data receiving unit 6 at regular intervals. Then, the encoding unit adds the redundant bit for error detection such as each parity bit and encodes it, and sends it as packet data. 8 collects a plurality of packet data transmitted from the encoding unit 7,
It is a data block forming unit that adds information necessary for communication between modulator / demodulators such as a transmitting station number and a receiving station number to generate one data block and outputs it to the modulating unit 4. Reference numeral 9 is a data receiving unit for taking in the data block from the partner station whose digital signal is converted by the demodulating unit 5 and whose receiving station number matches the station number of the own station, and 10 is for receiving this data. This is a decoding unit that performs error detection on each packet data based on the redundant bit added to each packet data of the data block fetched by the unit 9, and requests retransmission of the data block when an error is detected. . Reference numeral 11 is a data storage unit that stores the packet data determined by the decoding unit 10 as having no error, in a predetermined order, and accumulates the data until all the data to the data terminal 1 is collected, and 12 is the data storage unit. When the data to be sent to the data terminal 1 is completed, the data sending unit sends the accumulated data to the data terminal 1. Next, the operation will be described. The data sent from the data terminal 1 to the partner station is sent to the modulator / demodulator 3 by digital signals of "1" and "0". In the modulator / demodulator 3, the data receiving section 6 receives the data of the digital signal and stores the data of one partner station therein. Data receiving unit 6
Sends the received and accumulated data to the coding unit 7, and the coding unit 7 divides the received data into fixed intervals, adds redundant bits for error detection such as parity bits to each of them, and encodes the data. Is sent to the data blocking unit 8 as packet data. The data block forming unit 8 collects a plurality of packet data received from the encoding unit 7 and adds information necessary for communication between modulator / demodulators such as a transmitting station number and a receiving station number to generate one data block. Then, the data block is output to the modulator 4. The modulator 4 converts this data block into an MSK signal and sends it to the wireless device 2. Upon receiving the data block converted into the MSK signal suitable for communication, the wireless device 2 puts it on the radio wave and transmits it to the partner station. On the other hand, the data block by the MSK signal transmitted on the radio wave from the other station by the same procedure as the above-mentioned procedure is received by the wireless device 2, sent to the modulation / demodulation device 3, and input to the demodulation unit 5. It The demodulation unit 5 converts the data of the MSK signal into digital signals corresponding to “1” and “0” and sends the digital signals to the data reception unit 9. The data receiving unit 9
From the data block from the demodulation unit 5, the one whose receiving station number is the same as the station number is selected and fetched, and it is sent to the decoding unit 10. When receiving the data block taken in by the data receiving unit 9, the decoding unit 10 detects each error based on the redundant bit added to each packet data, and when the error is detected, requests the retransmission of the data block. A signal to be generated is generated and output to the data blocking unit 8. Further, the packet data determined by the decoding unit 10 to have no error is sent to the data storage unit 11 and is stored in a predetermined order until all the data to the data terminal 1 are collected. When the data block requested to be retransmitted is retransmitted and the data to the data terminal 1 is completed in the data storage unit 11, the data transmission unit 12 transmits the data accumulated in the data storage unit 11 to the data terminal 1. . Here, even if the transmission line with the partner station is cut off before the data from one partner station is completed in the data storage unit 11 and data from another station is received, each station is based on the transmitter station number. If the data is individually sorted and stored in the data storage unit 11, the received data will not be confused. The data terminal 1 which has received the data from the partner station by this digital signal from the data transmission unit 12 of the modulator / demodulator 3
Performs predetermined data processing using it. In the above embodiment, the data receiving unit 6 stores data for one partner station, but data for a plurality of partner stations may be stored. FIG. 2 is a block diagram showing such an embodiment. The data blocking unit 8 sends a signal notifying the completion of transmission to the data receiving unit 6 every time transmission of data for one partner station is completed, and the data receiving unit 6
Clears the data of the corresponding partner station in the stored data. In the above embodiment, the case where the encoding unit 7 adds redundant bits for error detection such as parity bits has been described, but redundant bits for error correction such as Hamming code may be added. In that case, the decryption unit 10
When a non-correctable error is detected, a signal requesting retransmission is sent. In the above embodiment, the input / output of the modulator / demodulator 3 is an analog signal, but it goes without saying that it can be applied to the input / output of a digital signal.

【The invention's effect】

As described above, according to the present invention, data sent from a data terminal to a partner station is divided at regular intervals, redundant bits are added to it to generate packet data, and a plurality of packet data are collected and then demodulated. While sending the data block to which the information required for communication between devices is added to the modulator, the data block whose receiving station number matches the station number of its own station is taken in and the error of each packet data is detected or corrected. Since the packet data determined to be error-free is organized and accumulated in the data storage unit until the data to the data terminal is completed, the transmission line may be cut off during communication or some data may be incorrect. Even if there is, the data sent up to that point is sorted and accumulated in the data storage unit, and it can be adopted as it is, so the transmission line At the time of occurrence, or when an error occurs, it is not only necessary to retransmit only the insufficient data, but it is not necessary to control the modulator / demodulator from the data terminal when transmitting / receiving data, during which the data terminal executes other processing work. Since the received data is sorted and accumulated in the data storage unit, there is no problem even if the data terminal is not connected, or if you communicate with other stations during that time, all the other parties will eventually be connected. It has the effect of being able to receive data from stations.

[Brief description of drawings]

FIG. 1 is a block diagram showing a modulator / demodulator according to an embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG. 3 is a block diagram showing a conventional modulator / demodulator. 1 is a data terminal, 2 is a transmission line (radio device), 3 is a modulator / demodulator, 4 is a modulator, 5 is a demodulator, 7 is an encoder, 8 is a data blocker, 9 is a data receiver, and 10 is Decryption unit,
11 is a data storage unit. In the drawings, the same reference numerals indicate the same or corresponding parts.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04L 12/56

Claims (1)

[Claims] 1. A modulator for converting a digital signal from a data terminal into a transmission signal and transmitting it to a partner station, and a demodulator for modulating a transmission signal received from the partner station into a digital signal and sending it to the data terminal. In a modulator / demodulator having
An encoding unit that divides data to be transmitted from the data terminal to the partner station at regular intervals, adds redundant bits for error detection or correction to each of the divided data to generate packet data, and the encoding unit. A plurality of the packet data generated in the unit, and a data block forming unit that generates a data block in which information necessary for communication between modulator / demodulators is added to the collected packet data and sends the data block to the modulator; From the data block converted into a digital signal by the data receiving unit that takes in the one having the receiving station number that matches the station number of its own station, and each packet of the data block taken in by the data receiving unit A decoding unit that performs error detection or correction of the packet data based on the redundant bit added to the data, and the data end. Until it is flush data to a total, modem, characterized by comprising a data storage unit to organize storing data from said decoding unit.