JPH0453334A - Modulator-demodulator - Google Patents

Abstract

PURPOSE:To allow a MODEM itself to detect the reception state without a control load of a terminal equipment side by detecting the transmission/reception of a prescribed pattern and the reception state of the pattern in the inside of the MODEM. CONSTITUTION:A MODEM 300 used for data transmission consists of a modulation section 301, a demodulation section 302, an analog processing section 303, a fixed pattern generating section 304, a selector 305, a pattern detector 306, an error number counter 307 and a comparator 308. Then the inside of the MODEM 300 can detect the transmission/reception of a prescribed pattern and the reception state of the pattern. Thus, the MODEM itself can detect the reception state without imposing a control load onto a terminal equipment side.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fixed pattern transmitting and detectable modem.

[Conventional technology]

A facsimile machine is a typical example of data transmission using a conventional modem (hereinafter referred to as a "modem"). A schematic configuration diagram of this conventional facsimile machine is shown in FIG. In FIG. 5, 300 is a modulation section 301, a demodulation section 302
It is a modem consisting of an analog processing section 303 that performs A/D conversion, D/A conversion, etc., and modulates the transmission data from the terminal (in this case, more specifically, the control device of the facsimile main body) 310 and sends it to the line 320. Along with line 32
The configuration is such that the data on 0 is demodulated and delivered to the terminal 310 as received data. For example, in this facsimile communication, CCI TT standard V
21. The V27ter and V29 modems (bit rates 300 bps, 4800 bps, and 9600 bps, respectively) operate on the CCITT standard T.30 protocol. FIG. 6 shows an outline of this T,30 protocol. In the figure,
The thick line shows a tonal signal, the solid line shows a signal at V21 (300 bps), and the dotted line shows a signal at a message transmission rate using V27ter or V29. CNG is a calling tone signal, to which the called side responds with CED: called station identification signal. Then, the process moves to a binary code procedure using V21, and the called station sends a DIS (digital identification signal) indicating the capabilities of the called terminal to the calling station, and the calling station responds with DC3 (digital command signal). At the same time, the training signal specified by the CCITT V standard and TCP (1-Learning check signal)
Send by V27ter or V29. The called side checks the TCP signal, and if the check result is good, it returns a CFR (reception readiness confirmation) signal to the calling side, and actually
The calling party sends a page worth of messages with training included. Furthermore, if the calling side runs out of messages to send, it sends an EOP (end of procedure) signal, and the called side uses the MC.
In response to this, the calling party sends a DCN (disconnect command) signal and the line is actually disconnected.For example, in this T,30 protocol, the TCP (training check) signal is , the terminal 310 shown in FIG.
sets the modem 300 in advance to operate in V27ter or V29 mode, and then
10 as a setting transmission signal. When the modem 300 receives the TCP signal as a transmission signal from the terminal 310, the modulation section So1 modulates the transmission signal, and the analog processing section 303 performs predetermined analog processing on the signal, and transmits it to the backward line 320. Similarly, signals such as the DIS signal are transmitted in the same manner except that the modem 300 is set to the V21 mode from the terminal 310. On the receiving side, after the data on the line 320 is processed by the analog processing unit 303, the data is processed by the demodulation unit 3 of the modem 300.
02 and is passed to the terminal 310 as received data. At this time, the terminal 310 performs identification (discrimination) of the received signal.

[Problem to be solved by the invention]

In the conventional example described above, especially when transmitting and receiving TCP signals using V27ter and V29 modems, the transmitting terminal transmits a continuous "o" as the transmission data, and the receiving terminal transmits "°0°" as the received data. ° Receive data. At this time,
The receiving side performs a reception check using this received TCP data. An outline of this conventional reception check will be explained below. That is, if the modem 300 is fully operational and is set to a state where it is not affected by deteriorating factors such as distortion on the line 302, the received signal from the modem 300 to the terminal 310 is T.
The CP signal is maintained at a steady state of 0. However, modem 30
If the 0 is not in a complete state, a ``1'' level appears in the received signal as a reception error. For this reason, the number of these ゛°1°° levels is counted to determine whether or not reception is actually possible. Note that the TCP signal is actually over-received for about 1.5 seconds. In this way, when receiving a TCP signal, an error check function is required to detect the 1° level of the received signal, especially on the receiving side of the terminal 310. However, on the terminal side,
I am in charge of controlling the main body of the facsimile machine (for example, image reading control, image output control, etc.), and if I create the above TCP signal on the main body side and operate the modem, the load on the main body side is high (and troublesome). This required manual operation, which increased the burden.

[Means for Solving the Problems] The present invention has been made for the purpose of solving the above-mentioned problems, and includes the following configuration as a means for solving the above-mentioned problems. That is, the modulation/demodulation device used for data transmission includes pattern selection means for selecting one of a plurality of types of fixed patterns, fixed pattern generation means for generating the fixed pattern selected by the pattern selection means, and fixed pattern generation means for generating the fixed pattern selected by the pattern selection means. A transmitting means that selects either the pattern generated by the pattern generating means or the externally inputted transmission signal and transmits it for an arbitrary period, and a fixed pattern to be transmitted from the receiving side and a pattern actually transmitted from the receiving side. Fixed pattern detection means for matching, counting means for counting errors in the matching results, comparison means for comparing the counting errors in the counting means with a predetermined threshold, and detecting a receivable state based on the comparison result of the comparison means. and a detecting means for detecting. Alternatively, a fixed pattern generation means capable of selecting a plurality of types of fixed patterns, a coincidence detection means for detecting a match between a pattern generated by the fixed pattern generation means and a received data pattern, and a count of the number of mismatches between the coincidence detection means. a comparing means for comparing the count value of the counting means with a predetermined threshold; a detecting means for detecting the reception state based on the comparison result of the comparing means; and setting means that can be set. Alternatively, fixed pattern generation means from which a plurality of types of fixed patterns can be selected, a coincidence detection means for detecting a match between a pattern generated by the fixed pattern generation means and a received data pattern, and the number of mismatches between the coincidence detection means are counted. a comparing means for comparing a count value of the counting means with a predetermined threshold value, a detecting means for detecting a reception state based on a comparison result of the comparing means, and a control for controlling a counting time of the counting means. and means. [For use] With the above configuration, by making it possible to transmit and receive a predetermined pattern within the modem and detect the reception status of the pattern, it is possible to detect the reception status by the modem without any control burden on the terminal side. That is.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a modem schematically showing an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of this embodiment. In Figure 1, the same components as in Figure 5 are given the same numbers,
Detailed explanation will be omitted. This embodiment differs from the conventional one in that, on the data transmitting side, a fixed pattern generator 304 outputs a selected fixed pattern from among a plurality of held fixed patterns in accordance with a pattern selection signal from the host device 1oo, and a host device 100 A selector 305 selects the output signal from the fixed pattern generator 304 when the check signal is on, and selects the transmission signal from the host device 100 when the check signal from the host device 100 is off, and inputs the selected signal to the modulation section 301.
is added, and on the receiving side, demodulation 3
Output demodulation pattern from 02 and fixed pattern generator 30
a pattern detector 306 that synchronizes with the output fixed pattern from 4, further compares both patterns, and outputs an error occurrence signal when a mismatch between the two patterns, that is, an error bit is detected; An error number counter 307 that counts the error occurrence signal of 306, and the number of errors counted by the error number counter 307,
The results are compared with a predetermined threshold value given by the host device 100, and as a result, if the number of errors counted by the error number counter 307 is small, the reception quality signal is determined as a reception quality signal, and if the number of errors is large, the reception quality signal is determined as a reception quality signal. The difference is that a comparator 308 that outputs a received bad signal is added. Next, communication control in the apparatus of this embodiment having the above configuration will be explained in detail using the flowchart of FIG. If a transmission request is made to the apparatus of this embodiment and the other party makes a call, or if there is a call from line 320, the process proceeds to the control shown in FIG. 2. First, in step S1, it is checked whether there is a transmission request or a received call and a reception request has occurred. If there is a transmission instruction from the host device 100 and it is in the transmission state, the process advances to step S2, and the modulation section 301 and the demodulation section 3
02 setting operation mode (e.g. V21, V27ter,
V29 etc. operation mode) settings, fixed pattern generator 3
Transmission initialization processing such as selection of a generated pattern by sending a pattern selection signal to 04 is performed. This pattern selection signal consists of, for example, two signal lines, and is
A fixed pattern as shown in FIG. 3 may be selected by a combination of 2-bit signals starting from 00. The 511-bit pseudo-random pattern when the signal line is "'1.0" in FIG. 3 is composed of a 9-stage shift register used in a scrambler, etc., and an exclusive OR circuit. The same holds true for the 2047-bit pseudo-random pattern. Since these configurations are well known, detailed explanation will be omitted. Furthermore, in all cases within the modem 300, except for the analog processing section 303, a digital signal processor (DS) is used.
It is often composed of software using software such as P). As described above, when the transmission initialization process in step S2 is completed, a training signal (TCP signal of T, 30 protocol, etc.) is transmitted in steps S3 and s4 until the data to be transmitted becomes ready for transmission. If transmission is possible, the process advances from step S4 to step S5, and it is determined whether the check signal from the host device 100 is on or off. If the check signal is on, the process advances to step S6, where the fixed pattern generator 304 is energized and the selector 304 selects the output fixed pattern from the fixed pattern generator 304 and outputs it to the modulation section 301. Then, proceed to step SIO. On the other hand, if the check signal is off, the process advances from step S5 to step S8, and the selector 305 selects the host device 10.
The transmission signal from 0 is selected and output to the raw modulation section 301. Then, proceed to step SIO. In step SIO, the modulation unit 301 performs predetermined modulation processing on the input signal and sends it to the analog processing unit 303, where it is converted into a predetermined corresponding analog signal, output to the line 320, and transmitted to the called destination device. be done. Then, in step Sll, it is checked whether data transmission has ended or not, and if there is still data to be sent, the process returns to step S5 to continue data transmission. Here, if the data transmission is completed, the process advances from step SIL to step S15, where post-processing is executed, the calling line is restored, and the process is ended. In addition, in the above explanation, at the time of transmission, when sending out the TCF signal of the T.30 protocol, the host device 100
is all “0°” during the modem initialization process in step S2.
° It is sufficient to select and output the pattern and turn on the check signal during the TCP signal period, which is the output timing of the training signal. Next, control in the receiving mode when a call from line 320 is detected will be explained. If a call from the line 320 is detected and the host device 100 sets the reception mode, the process advances from step S1 to step S20, and as in step S2, the modulation unit 301
, and the set operation mode of the demodulator 302 (for example, V21.
V27ter. Reception initialization processing such as setting the operating mode (such as V2.9) and selecting a fixed pattern by sending a pattern selection signal to the fixed pattern generator 304 is performed. Note that at this time, the threshold value of the reception error signal for the comparator 308 is also initialized and output. This is achieved by, for example, providing the comparator 308 with a threshold table similar to that shown in FIG. The threshold value may be determined by searching this threshold value table using an input bit pattern of 100, or it may be directly set as an output of threshold data from the host device 100. Next, in steps S21 and S22, a training signal (TCF signal of T, 30 protocol, etc.) is received from the partner device until it actually becomes ready to receive data. When the state is ready for reception, the process proceeds from step S22 to step S23, where the analog processing unit 303 receives and receives the transmission data from the other party on the line 320, performs predetermined analog processing, and demodulates the data at the demodulation unit 302. . Then, in step S24, the on/off status of the check signal from the host 100 is checked. If the check signal is on, the process advances to step S25, where the fixed pattern generator 304 is operated, and the pattern detector 306 detects the fixed pattern. Bakun matching (comparison) is performed between the fixed output pattern from the generator 304 and the demodulated output.If there is a pattern that cannot be matched (if some bits have received errors), an error signal is sent. Therefore, the error counter 307 sends out step 32.
When this error signal is received in step 6, it is counted up. Therefore, in step S27, the comparator 308 compares the threshold value set in the previous step S20 with the error counter 3.
Compare with the count value of 07. and step 328
The comparison result is output to the host device 100. As a result of the comparison, when the count value of the error counter 307 is equal to or higher than the set value, a signal indicating poor reception status, such as a ゛°l゛ level signal, is output to the host device 100 as a reception quality signal, and the error counter 307 counts. When the value is less than the set threshold, a signal indicating a bad odor in the received receipt, for example, a ゛°O°° level signal is output as a reception quality signal. and step S
Proceeding to step 30, it is checked whether or not data reception has been completed. If data reception has not been completed, the process returns to step 323 and continues the data signal reception process. On the other hand, if the check signal is off in step S24, the process proceeds to step S35, where the output signal of the demodulator 302 is controlled to be sent as a received signal to the post device 100 as it is. Then, the process advances to step S30. If the reception of data is completed in step S30, the process advances from step S30 to step S15, and after performing post-processing with the sending device, the connection line 320 is restored, and the process ends. Note that during reception, the host device 100 sets all zeros during the initialization process in step S20, as well as during transmission.
All you have to do is select the °° pattern. During the training period, for example, when communicating TCP signals of T and 30 protocols, it is sufficient to simply turn on the check signal and further judge the level of the signal indicating the quality of reception from the modem 300. As explained above, according to this embodiment, by making it possible to transmit and receive a predetermined pattern within the modem 300 and detect the reception state of the pattern, the modem 300 can detect the reception state by itself without any control burden on the terminal side. This made it possible.

[Second Embodiment] In the above explanation, during the training period, for example, during TCP signal communication using the T, 30 protocol, the check signal is always turned on, and other controls are not performed to indicate the quality of reception from the modem 300. We have explained an example of determining the signal level, but for example, in TCP signal communication, the signal state lasts about 1.5 seconds, and the evaluation of reception quality evaluates the reception state during the entire 1.5 seconds. Instead, it is desirable to check for errors only for one second after the modems on both sides enter stable operation. A second method according to the present invention in which the reception quality is evaluated in the second half of the second second period.
Examples will be described below. In the second embodiment, a counter reset signal of the error counter 306 (counter reset signal shown by a chain line in FIG. 1) is used for, for example, 0.5 seconds after the carrier signal from the partner device is detected (from the CD signal ON). The error counter 307 can be kept in a reset state by turning on the error counter 307. In this way, by controlling the counter reset signal, the evaluation period of line reception quality can be arbitrarily controlled.

[Third Embodiment] In the above embodiments, the clear signal of the error counter is externally controlled as the error counting start time control means to set the reception quality evaluation period, but the present invention is limited to the above example. (A separate timer circuit is provided in the modem 300, and the initial value of this timer circuit is input from the outside by an evaluation period table similar to the threshold table of the comparator 308, and input from the host device 100.) All you have to do is search this evaluation period table based on the bit pattern and set the set timer value of the timer circuit.The receiving side circuit configuration of the modem device 300 configured in this way is shown in FIG. 1, a timer initial value setting signal is output from the host device 100 instead of the counter clear signal, and a timer circuit 309 that receives this signal is newly added. The apparatus 100 is shown in step S in FIG.
In the initialization process 20, a timer initial value setting signal is output to select a timer value to be set in the timer circuit 309 of the evaluation period table. When a carrier signal (CD signal) from the partner device is detected, the timer circuit 309
start the timer. And this timer circuit 3
09 causes a time-up, and when the set timer time elapses, a time-up signal is output to the error counter 307. This time-up signal corresponds to the counter clear signal shown in FIG. 1, and the counter reset is canceled when the time-up signal is turned on. By controlling as described above, the timer circuit 309
It becomes possible to set the setting timer value to an arbitrary value, and as a result, the reception quality evaluation period can be controlled to an arbitrary period. In this case, the host device 1, which is an external terminal device,
00, there is no need to count the time since the CD signal was turned on, and the effect of further reducing the burden on the connected host device can be obtained.

[Other Examples]

In the above-mentioned embodiment, a facsimile machine was considered as a usage mode of the modem, and the effectiveness of the present invention was described in particular in the case of TCP signals in the T, 30 protocol, but the present invention is not limited to this mode. None. In particular, if we focus only on the TCF signal, all fixed patterns can be set to "Ooo," but the present invention is structured so that other patterns (such as a 511-bit pseudo-random pattern) can be selected. As an application, the transmission and
There is a reception test. Conventionally, in this type of test, it has been necessary to use a pseudo host device 100 called a modem tester, which has fixed pattern sending and detection functions, when conducting a two-modem test. In contrast, the present invention has a function to generate and detect a 511-bit pseudo-random pattern specified by test standards (CCITTV56, etc.), so if the check signal of the modem is turned on, the modem-to-modem test can be performed on the modem. It can be easily done without requiring a tester. In addition to modem shipping tests, face-to-face tests can be easily performed in the field without a tester, and maintenance by service personnel and the like can be facilitated. As explained above, according to each of the above embodiments, the modem 30
By providing a fixed pattern sending and detecting function 304 inside 0, in the case of a modem device connected to a FAX machine, TCP signal sending and checking functions are no longer necessary on the host device 100 side, and the host device The burden of modem control on the 100 side can be greatly reduced. In addition, since the fixed pattern can be set as a test pattern that is different from the TCP signal, it is possible to perform modem face-to-face tests at the time of shipment and in the field without the need for special equipment such as a modem tester. It has the advantage of being easy to perform. Further, since the error threshold value can be controlled by the host device, for example, when checking a TCP signal, the strength of the check can be freely adjusted, and the transmission and reception quality level can be optimized depending on the communication partner. Furthermore, by changing and outputting this threshold value at the time of shipment or during a modem face-to-face test during delivery settings, etc., modem and line quality can be checked in more detail. Furthermore, since the error counting start time can be controlled externally, the check time can be arbitrarily controlled when checking the TCP signal. Therefore, it is possible to support training between devices with different TCP signal transmission times, for example, facsimile machines with different TCP signals. Furthermore, by making the check time variable depending on the communication partner, the quality of transmission and reception can be made variable.

【Effect of the invention】

As explained above, according to the present invention, by making it possible to transmit and receive a predetermined pattern and detect the reception state of the pattern within the modem, the control burden on the terminal side is eliminated (the modem and the modem can independently detect the reception state). Furthermore, since the configuration allows various fixed check patterns to be set, modem face-to-face tests can be performed at the time of shipment and in the field without the need for special equipment such as a modem tester. It has the advantage of being easy to perform.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a modem according to an embodiment of the present invention, FIG. 2 is a flowchart showing the communication control operation of this embodiment, and FIG. 3 shows the types and types of patterns generated in the fixed pattern generation circuit of this embodiment. FIG. 4 is a block configuration diagram showing the configuration of a receiving modem device according to a third embodiment of the present invention; FIG. 5 is a block configuration diagram of a conventional modem; FIG. 6 is a diagram showing a generation pattern selection selection signal. FIG. 3 is a diagram illustrating a T,30 protocol between facsimile devices. In the figure, 300... modem, 301... modulation section, 30
2... Demodulation section, 303... Analog processing section, 304
...Fixed pattern generator, 305...Selector, 3
06... Pattern detector, 307... Error number counter, 308... Comparator, 309... Timer circuit,
310...terminal, 320...line.

Claims (5)

[Claims] (1) A modulation/demodulation device used for data transmission, which includes pattern selection means for selecting one of a plurality of types of fixed patterns, fixed pattern generation means for generating the fixed pattern selected by the pattern selection means, and fixed pattern generation means for generating the fixed pattern selected by the pattern selection means; A transmitting means that selects either the pattern generated by the pattern generating means or the externally inputted transmission signal and transmits it for an arbitrary period, and a fixed pattern to be transmitted from the receiving side and a pattern actually transmitted from the receiving side. Fixed pattern detection means for matching, counting means for counting errors in the matching results, comparison means for comparing the counting errors in the counting means with a predetermined threshold, and detecting a receivable state based on the comparison result of the comparison means. What is claimed is: 1. A modulation/demodulation device comprising a detection means for detecting. (2) A modulation/demodulation device used for data transmission, including a fixed pattern generating means capable of selecting a plurality of types of fixed patterns, and a coincidence detecting means for detecting a match between a pattern generated by the fixed pattern generating means and a received data pattern. , a counting means for counting the number of mismatches of the coincidence detecting means, a comparing means for comparing the count value of the counting means with a predetermined threshold value, and a detecting means for detecting a reception state based on the comparison result of the comparing means; A modulation/demodulation device comprising: setting means capable of setting a comparison threshold value in the comparison means to an arbitrary value. (3) A modulation/demodulation device used for data transmission, including a fixed pattern generating means capable of selecting a plurality of types of fixed patterns, and a coincidence detecting means for detecting a match between a pattern generated by the fixed pattern generating means and a received data pattern. , a counting means for counting the number of mismatches of the coincidence detecting means, a comparing means for comparing the count value of the counting means with a predetermined threshold value, and a detecting means for detecting a reception state based on the comparison result of the comparing means; A modulation/demodulation device comprising: control means for controlling counting time in the counting means. (4) Fixed pattern generation means is at least all “0”
4. The modulation/demodulation device according to claim 1, wherein the modulation/demodulation device is capable of generating a pattern and a 511-bit pseudo-random pattern. (5) The modulation/demodulation device according to claim 4, wherein the control means controls the counting time by controlling a count clear signal in the counting means.