JP4439415B2 - Facsimile modem device - Google Patents

Description

  The present invention relates to a facsimile communication apparatus (modem apparatus) using a silicon DAA circuit in a facsimile apparatus and a transmission / reception method thereof.

Conventionally, since PCM data of facsimile IG3 (G3) includes transmission PCM data and reception PCM data, at least two circuits for converting to an analog signal are required, and the transmission analog signal and the reception analog signal are added. A circuit to do was necessary.
Therefore, a communication terminal device such as a facsimile which eliminates the need for a transmission analog signal and a reception analog signal has been proposed. For example, in the “communication terminal device” described in Japanese Patent Application Laid-Open No. 2004-112682 (see Patent Document 1), a modem DSP that performs facsimile communication using a telephone line using silicon DAA is provided with a μlaw / Alaw conversion function and sampling. It is disclosed that it can be realized by adding a frequency conversion function.

  That is, the “communication terminal device” described in the above publication includes a modem DSP (Digital Signal Processor) that performs transmission data generation and PCM conversion processing, and ISDN (Integrated Services). Transmission data generated by the modem DSP and the ISDN control unit that performs transmission and reception with other devices via a digital network), the PCMI / F that exchanges voice encoded data between the ISDN control unit and the ISDN control unit And a monitor audio data generation unit that generates monitor audio data by adding transmission data sent from the ISDN control unit via the PCMI / F.

  In realizing the above-described invention, the number of parts added to realize the IG3 function is as small as possible, and it is more advantageous in terms of cost to use the part that can be used for communication from the telephone line as it is. In the case of IG3 communication, the ISDN interface transmits / receives data at a frequency of 8 KHz, and the modem processing modulates / demodulates data with a sampling frequency suitable for a modem such as 9600 Hz, so sampling conversion is necessary. Control is required to deliver. Furthermore, in order to monitor the communication status when performing IG3 communication, when sending data to the silicon DAA, it is necessary to pass data at an 8 KHz period different from ISDN, and control is required. These are not presented or disclosed in the above publication.

JP 2004-112682 A

  As described above, in conventional facsimile modem processing using IG3, many parts are added to realize the IG3 function, and modulation / demodulation processing is also required with sampling frequency data.

(the purpose)
An object of the present invention is to solve the above-mentioned conventional problems, simplify the data structure, data transfer method, and control method during IG3 communication, and realize G3 communication via a telephone line using silicon DAA. It is an object of the present invention to provide a facsimile modem apparatus and a transmission / reception method thereof that can be realized at low cost by reducing the added data configuration and data transfer control.

  The modem apparatus for facsimile according to the present invention comprises an analog interface with a silicon DAA analog telephone line, a digital interface with an ISDN line, a modem signal used in facsimile communication via an analog telephone line, and a signal used on an ISDN line. A bi-directional conversion function, an interrupt processing mechanism for receiving serial communication requests from both silicon DAA and ISDN and supplying necessary data to both when performing G3 communication via an ISDN line, and a buffer configuration, As a buffer configuration, an extended configuration is adopted when G3 communication via ISDN is performed based on communication using a telephone line using silicon DAA, and the data transfer path can be changed by control by software.

  According to the present invention, a modem DSP that realizes both G3 communication via a telephone line using silicon DAA and G3 communication using ISDN can be obtained by adding a little memory and a program to a DSP that realizes a conventional modem. Can be provided.

FIG. 1 is an overall configuration diagram of a modem system including a DSP of the present invention.
A modem DSP chip 11 which is a modem DSP unit includes a DSP unit 12 that performs digital signal processing for modulation / demodulation processing of a FAX signal, a system side device 18 of silicon DAA, and a serial interface unit 15 for a system side device that transmits and receives data serially. And an ISDN interface unit 24 and an ISDN interface serial interface unit 16 for serially transmitting and receiving data. In addition, a line side device 21 for transmitting and receiving analog signals, a speaker circuit 19 and a speaker 20 for monitoring are provided. The ISDN interface unit 24 is built in the ISDN communication block 23. The DSP unit 12 includes a sampling conversion function unit 13 and a μ / Alaw conversion function unit 14.

In this embodiment, a μ / Alaw conversion function unit 14 is provided as a means for bidirectionally converting a modem signal used in facsimile communication using an analog telephone line and a signal used on an ISDN line. When G3 communication is performed, an interrupt processing mechanism unit that receives serial communication requests from both the silicon DAA and ISDN and supplies necessary data to both is provided in the DSP unit 12.
In addition, the configuration of the buffer built in the interface units 15 and 16 is based on the case of communication using a telephone line using silicon DAA, and is extended when performing G3 communication via ISDN. The transfer route is changed.

  In the case of FAX communication with the PSTN line, transmission / reception data from the DSP unit 12 is converted by the system side device serial interface unit 15 into an interface format for the modem CODEC. The interface format for the modem CODEC has a 16-bit linear data length, and the sampling frequency varies depending on the phase to be connected and the symbol rate to be connected. The system side device 18 corresponds to the interface format for the modem CODEC, and the FAX signal from the DSP unit 12 is converted into a signal passing through the insulation capacitor C by the system side device 18. The FAX signal of the DSP unit 12 transmitted through the insulation capacitor C is transmitted to the line as an analog signal by the line side device 18. The system side device 18 has an analog output for speaker output, and is designed so that the communication status can be monitored by adding the speaker 20 and some analog circuits thereto.

FIG. 2 is a diagram showing a general data configuration inside the modem DSP when G3 communication is performed over a telephone line when silicon DAA or modem CODEC is used.
Hereinafter, the flow of data during conventional G3 communication will be described.
1) Transmission data flow A modem modulation unit (not shown) generates transmission data TX SAMPLE 38 corresponding to one symbol. This is once transferred to the transmission data buffers (1A) 36 and (1B) 34. The transmission data buffers 36 and 34 have a double configuration, and are A side and B side, respectively.
When the data generated by the modem unit is transferred to one side, the other transmission data is transferred to the transmission data shift register 32 and output serially every time an interrupt occurs.
When the generation of the transmission data for the buffer size is completed, the modem transmission unit does not operate and waits for all the data to be transmitted from the opposite buffer 34 or 36. When all the data has been sent, the buffer surface is replaced, and the data already generated and transferred by the transmission unit is sent to the transmission data shift register 32 at every interruption, and transferred to the modem CODEC 31 at every serial clock. The modem transmission unit transfers the created transmission data to the opposite buffer surface.

2) Received Data Flow Next, the received data flow will be described. The serial reception data is held in the reception data shift register 33, and an interrupt is generated at the time when the 16 bits are aligned and transferred to the reception data buffers (1A) 37 and (1B) 35. The reception data buffers 37 and 35 also have a double configuration, and are referred to as A side and B side, respectively. Received data is transferred to one side of the buffers 37 and 35 every time an interrupt occurs, and the modem takes out the data from the other buffer 37 or 35 and demodulates it as received data. When the received data for the buffer size is demodulated, the modem demodulator (not shown) stops operating and waits until the buffer 37 or 35 on the opposite side is full. When the buffer 37 or 35 is full of received data, the target buffer surface is replaced, the demodulator extracts and demodulates the stored received data, and in the interrupt process, the received serial data is empty. Store it in the buffer plane.

FIG. 3 is a data flow diagram according to an embodiment of the present invention.
When the communication status is monitored from the speaker output of the silicon DAA 41 at the time of executing the IG3 communication, it is necessary to have two systems of serial interfaces, the silicon DAA 41 and the ISDN 42. The silicon DAA 41 is used for communication monitoring. The received data does not need to be processed, and the transmission data is converted into PCM data by decoding the IG3 transmission data and the IG3 reception data when an IG3 communication interrupt occurs. The gain is multiplied and added to obtain speaker output data 47.

  If the sampling frequency of the silicon DAA 41 is set to 8 KHz as in the ISDN-IF 42, basically no excess or deficiency occurs. However, even though ideally the same, there is actually a slight deviation between both clocks. Therefore, the generated speaker data is held in the buffer SPK OUT 47 having a depth of 2. When the sampling frequency of the silicon DAA 41 is slightly slow, if two or more speaker output data already exist in the SPK OUT buffer 47, the data is discarded. As a result, the continuity of the monitor data is interrupted, but there is no need to increase the buffer size. If the sampling frequency of the silicon DAA 41 is faster, this can be dealt with by sending the same one that was sent last time to the silicon DAA 41.

  The ISDN transmits and receives data at 8 KHz and 8 bits (64 Kbps). However, the data is taken out from the transmission data buffers (2A) 50 and (2B) 48 for each 8 KHz interrupt, and the received data is also received at each 8 KHz interrupt. ) 51 and (2B) 49. Similarly to the buffers 52 to 55, the transmission / reception data buffers 48 to 51 have a double structure, which is an exchange on an interrupt basis and an exchange on the modem processing side. The modem modulation unit (not shown) is completely different from the communication using SDAA, the transmission data generated in the transmission data buffers 52 and 54 is written, and the modem demodulation unit (not shown) is taken out from the reception data buffers 52 and 54. . The rate conversion sequencer performs data transfer between the transmission data buffers 52, 54 and 48, 50 and data transfer between the reception data buffers 53, 55, 49, 51.

FIG. 5 is a processing flowchart of the rate conversion sequencer in the present invention.
Hereinafter, the process will be described for each step of FIG.
(A) Transmission data flow 1) It is confirmed whether or not there is a vacancy in the transmission data buffer (2) 48, 50. If there is no vacancy, the process proceeds to 7) and subsequent received data processing.
2) If the samples generated at the previous rate conversion remain without being transferred, transfer them.
3) It is confirmed whether there is modem modulation data in the transmission data buffer (1) 52, 54. If there is no modem modulation data, the process proceeds to 7) and subsequent reception data processing.

4) It is confirmed whether or not there is a vacancy in the transmission data buffer (2) 48, 50. If there is no vacancy, the process proceeds to 7) and subsequent received data processing.
5) Take out one modulated data from the transmission data buffer (1) 52, 54, perform sampling rate conversion by the sampling conversion function unit 13, and execute conversion to μ / Alaw by the μ / Alaw conversion function unit 14. . As a result of the conversion, 0 to 2 8 KHz ISDN communication data are output. If the sampling frequency of the modem modulation data is greater than 8 KHz, 0 or 1 data is output, and if it is less than 8 KHz, 1 or 2 data is output.
6) Transfer the sample output after rate conversion. When it is 0, nothing is done and when it is 1, it is transferred. When there are two, the transfer is performed only when the transmission data buffers (2) 48 and 50 are empty. If there is no free space, it is transferred in the above 2) when the rate converter is called next time.

(B) Received Data Flow Next, received data processing will be described.
7) If the sample generated at the time of the previous reception data rate conversion remains without being transferred, and the reception data buffers (1) 53 and 55 are empty, this is transferred.
8) Check whether there is data in the received data buffer (2) 49, 51, and if not, jump to 12).
9) One piece of data is read from the received data buffer (2) 49, 51, decoded into PCM data, and the sampling conversion function unit 13 performs sampling rate conversion.
10) Store the data output after data rate conversion in the buffer as a received data string after rate conversion.
11) If there is rate-converted data and there is an empty reception data buffer, it is transferred.
12) It is determined whether or not a modem modulation / demodulation start flag (MODEL ENABLE) can be set. When all the data in the transmission data buffer (1) 52, 54 has been transferred, and when the reception data buffer (1) 53, 55 is completely filled with data for modem demodulation, the modem modulation data is stored. The target buffer for rate conversion as transmission data is replaced, and the surface for aligning the data taken out by the modem receiver for demodulation and the target surface for storing the data after rate conversion are replaced. Then, MODEL ENABLE is set to restart the modem modulation / demodulation processing. MODEL ENABLE is set to 0 when the modulation unit and the demodulation unit set all the modulation data in the transmission data buffers (1) 52 and 54 and demodulate all the data in the reception data buffers (1) 53 and 55, respectively.
The above is the description of data flow and data control.

FIG. 4 is an explanatory diagram of the operation of the speaker output data creation unit.
The speaker output data creation unit includes a sampling conversion function unit 13 and a μ / Alaw conversion function unit 14 in the DSP unit 12 of FIG. 1, a system side device 18, and a speaker circuit 19.
The transmission μ / Alaw data 61 converted by the μ / Alaw conversion function unit 14 and the reception μ / Alaw data 62 converted by the μ / Alaw conversion function unit 14 are decoded by the decoding circuits 63 and 64, respectively. Multiplying circuits 65 and 66 multiply the output by the control input of the transmission gain coefficient and the reception gain coefficient, and output the result. The addition circuit 67 adds them and outputs them to the buffer.

FIG. 6 is a detailed block diagram of a DSP according to an embodiment of the present invention.
A DSP 72 having a system side device serial interface unit 75 that is an interface with the system size device (SDAA) 18 and an ISDN interface serial interface unit 76 that is an interface with the ISDN interface unit 24 and that operates according to a program. And a data memory 73 for storing programs and data, a program memory 74, and a host-interface unit 71 serving as an interface with a host CPU (not shown).
The data shown in FIGS. 2 and 3 for performing communication with the telephone line via the SDAA 18 and IG3 communication is configured on the data memory 73. The control shown in the flow of FIG.
The buffer configuration shown in FIG. 3 is based on the case of communication using a telephone line that uses the silicon DAA, and an extended configuration is used when performing G3 communication via ISDN, and the data transfer path is changed by software control. ing.

  As described above, in this embodiment, the processing program in the case of IG3 is added to the modem DSP 70 that realizes communication with the conventional silicon DAA, and the data structure is also expanded for IG3 communication, that is, program processing and data. With a slight addition of the memory area, it is possible to realize a DSP chip having both functions of IG3 communication in G3 communication over a telephone line.

  If the flow procedure shown in FIG. 5 is programmed and stored in a recording medium such as a CD-ROM, the program is downloaded via a network if requested from a Web server or other computer. The program can be sold, loaned, and generalized.

1 is an overall configuration diagram of a modem system including a DSP according to an embodiment of the present invention. It is a data flow diagram of a modem system including a conventional DSP. It is a data flow figure concerning one example of the present invention. It is a block diagram of the speaker output data preparation part in this invention. It is a process flowchart of the rate conversion sequencer in this invention. FIG. 3 is a detailed block diagram of a modem DSP chip according to an embodiment of the present invention.

Explanation of symbols

11: modem DSP chip 12: DSP unit 13: sampling conversion function unit 14: μ / Alaw conversion function unit 15: serial interface unit for system side device 16: serial interface unit for ISDN interface 18: system side device 19: speaker circuit 20 : Speaker 21: Lyside device 22: Peripheral circuit 23: ISDN communication block 24: ISDN interface unit 31: Modem CODEC
32: Transmission data shift register 33: Reception data shift register 34, 36: Transmission data buffer (1A, 1B)
35, 37: Receive data buffer (1A, 1B)
38: Transmission sample data TX SAMPLE
39: Received sample data TX SAMPLE
41: Silicon DAA
42: ISDN-IF
43, 45: Transmission data shift register 44, 46: Reception data shift register 47: SPK OUT (speaker output)
48, 50: Transmission data buffer (2A, 2B)
49, 51: Receive data buffer (2A, 2B)
52, 54: Transmission data buffer (1A, 1B)
63, 55: Received data buffer (1A, 1B)
61: Transmission μ / Alaw data 62: Reception μ / Alaw data 63, 64: Decoding circuit 65, 66: Multiplication circuit 67: Addition circuit 70: Modem DSP chip 71: HOST-IF
72: DSP
73: Data memory 74: Program memory 75: SDAA serial interface unit 76: ISDN serial interface unit C: Insulation capacitor

Claims (7)

G / Facsimile communication control with ISDN line via ISDN interface serial interface provided with DSP / μAaw conversion function and sampling frequency conversion function in DSP unit that performs facsimile communication control using telephone line using silicon DAA A facsimile modem device for performing
First and second transmission data buffers alternately storing modem-modulated transmission data up to a capacity;
A transmission data shift register for converting the transmission data of the first and second transmission data buffers into serial transmission data and transferring it to the modem CODEC;
A reception data shift register for converting serial reception data transferred from the modem CODEC into parallel reception data;
And having first and second received data buffers alternately storing parallel received data converted by the received data shift register until the capacity is full,
IG3 transmission connected between the first and second transmission data buffers and the transmission data shift register and transmitted from the first and second transmission data buffers when IG3 transmission data is transmitted through the ISDN line Third and fourth transmission data buffers for alternately storing data up to a capacity and sending the data to the transmission data shift register;
When receiving the IG3 reception data on the ISDN line, it is connected between the reception data shift register and the first and second reception data buffers, and the IG3 reception data sent from the reception data shift register is filled up to the capacity. Third and fourth received data buffers for alternately storing and transferring to the first and second received data buffers;
At the time of transferring the IG3 transmission data from the first and second transmission data buffers to the third and fourth transmission data buffers, the IG3 transmission data is converted into a sampling rate by the sampling conversion function and the μ / Convert to μ / Alaw with the Alaw conversion function,
When transferring the IG3 reception data from the third and fourth reception data buffers to the first and second reception data buffers, the IG3 reception data is decoded into PCM data by the μ / Alaw conversion function. And a rate conversion sequencer for converting the sampling rate by the sampling conversion function. The facsimile modem device according to claim 1,
A serial interface unit for a system side device that converts transmission / reception data from a DSP unit into an interface format for a modem CODEC in the case of facsimile communication with the analog line;
A system side device that supports the interface format for the modem CODEC and converts the FAX signal from the DSP unit into a signal that passes through an insulation capacitor;
A line side device for transmitting a facsimile signal from the DSP unit transmitted through the insulating capacitor to the line as an analog signal;
The analog output of the speaker output from the system side device, a facsimile modem apparatus characterized by comprising a speaker circuit for monitoring the communication status is transmitted to the speaker. The facsimile modem device according to claim 2,
The speaker circuit is
A first decoding circuit for decoding the transmitted mu / ALAW data more converted to mu / ALAW conversion function of DSP portion,
A second decoding circuit for decoding received μ / Alaw data converted by the μ / Alaw conversion function in the DSP unit ;
A first multiplication circuit that inputs data decoded by the first decoding circuit and multiplies a transmission gain coefficient;
A second multiplication circuit that inputs data decoded by the second decoding circuit and multiplies the reception gain coefficient;
A facsimile modem apparatus comprising: an adder circuit for adding the outputs of the first and second multiplier circuits and outputting the sum to a buffer. A facsimile modem apparatus according to any one of claims 1 to 3, comprising:
The rate conversion sequencer
A program-controlled functions of the DSP unit,
The third, if there is a fourth air in the transmission data buffer, and transfers the data remaining to be transferred Ki out to when converting previous rate,
The first, if there is a modem modulation data to the second transmission data buffer,
Upper Symbol third accesses the fourth transmission data buffer, performs a check of whether there is a free space,
If there is a space, the first, accesses the second transmit data buffer, it is removed one modulated data from the buffer, along with make sample rate conversion at a sampling conversion function, in mu / ALAW conversion function mu A modem apparatus for facsimile which is converted to / Alaw. The facsimile modem apparatus according to claim 4, wherein
The rate conversion sequencer
In the conversion result to μ / Alaw by the μ / Alaw conversion function,
When the sampling frequency of modem modulation data is greater than 8 KHz and 0 or 1 data is output, or when the sampling frequency of modem modulation data is less than 8 KHz and 1 or 2 data is output,
When the output data is 0, nothing is done. When the output data is 1, the output data is transferred to the third and fourth transmission data buffers. When the output data is 2, the third and fourth transmission data buffers are free. A facsimile modem apparatus, wherein the output data is transferred to the third and fourth transmission data buffers only in some cases. A facsimile modem device according to any one of claims 1 to 5, comprising:
The rate conversion sequencer
A program-controlled functions of the DSP unit,
The third, the fourth received data buffer, it remains to be transferred data that was in the previous reception data rate conversion, the first, if there is a space in the second received data buffer, the data Forward,
The third, by accessing the fourth received data buffer, performs a check of whether there is data,
If you have data,
Third, by accessing the fourth received data buffer, read one data from the buffer, it decodes the PCM data the data decoding circuit performs Oite sampling rate conversion on the sampling conversion function,
Data output after data rate conversion is stored in the first and second received data buffers as a received data string after rate conversion,
There are rate converted data, the first, if there is a space in the second received data buffer, and transfers the data
Facsimile modem device comprising a call. A facsimile modem device according to claim 6,
The rate conversion sequencer
When all the data in the first and second transmission data buffers has been transferred, the first and second transmission data buffers are switched between the modem modulation data storing side and the rate converting side as transmission data,
When all of the first and second received data buffers are filled with data for modem demodulation, the first and second received data buffers are arranged on the side where the modem receiving unit aligns data taken out for demodulation. , Replace the rate converted data with the store side,
When all the modulation data is set in the first and second transmission data buffers, a flag is set to restart the modem modulation process,
A facsimile modem apparatus, wherein when all data in the first and second received data buffers are demodulated, a flag for resuming modem demodulation processing is set.

Images