JPH0737401Y2 - Signal transmission level control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention relates to a signal transmission level control device, and more particularly, to a signal transmission level control device for controlling the transmission level of a signal transmitted to a line to a required regulation value. Regarding

(Prior Art) It is regulated by law that the transmission level of a signal transmitted to a line of a device using a public line, such as a facsimile device, is within a certain allowable value. It depends on the country and the type of signal. Therefore, a facsimile machine or the like needs to satisfy the regulation value of each country in which it is installed.

Therefore, conventionally, as shown in FIG. 6, an amplifier 2 is provided in a communication device 1 and a signal modulated by a modem 3 into a signal form suitable for a line is amplified by the amplifier 2 to a size within a regulation value range. ing. The signal amplified by the amplification width 2 is sent to the line 5 via the transformer 4, and the transformer 4 is connected to the communication device 1 and the line 5.
It is to electrically insulate and. This amplifier 2
An operational amplifier 6 is used as a control signal, and the feedback resistance (gain resistance) 7 is adjusted to adjust the signal transmission level to a level within a regulation value. A variable resistor is used as the gain resistor 7, and is adjusted at the time of shipment of the communication device 1 or at the time of installation of the communication device 1 according to the regulation value of the signal transmission level of the installation country.

(Problems to be solved by the invention) However, in such a conventional signal transmission level control device, a variable resistor is used as a gain resistor of an amplifier for amplifying a transmission signal, and the gain resistor is manually adjusted. Therefore, the gain resistance is fixed after adjusting once,
The transmission level could not be adjusted to the median of the regulation value (allowable amount) for each signal, and there was a risk that the signal transmission level would deviate from the regulation value.

That is, the transmission level of the signal varies depending on the country, and also varies within the same country depending on the signal. However, when adjusting using a variable resistance as the gain resistance,
Once adjusted, it is fixed, and even if the transmission level of each signal can be kept within the range of the regulation value, if the regulation value differs depending on the signal, some signals deviate from the center of the regulation value. Therefore, if the transmission level of the signal input to the amplifier fluctuates due to variations in circuit elements before the amplifier, the transmission level of the signal amplified by the amplifier and transmitted to the line may deviate from the regulation value. Further, as a characteristic of the modem, the output level of the signal changes depending on the frequency of the signal and the like, and even if the regulation value is the same, there is a possibility that it may deviate from the regulation value depending on the type of signal.

Therefore, the present invention provides a signal transmission level control device by transmitting a signal after setting a transmission level for each signal type to be transmitted when transmitting various signals to a communication partner. It is an object of the present invention to always keep the sending level required for various signals within a regulated value without being affected by the variation of the circuit elements that constitute it.

(Structure of the Invention) In order to achieve the above object, the invention according to claim 1 is a signal amplification means for amplifying a signal to be sent to a line, and an amplification factor setting means for variably setting the amplification factor of the signal amplification means. A memory means for storing in advance a transmission level required for each signal type transmitted to the line; a reading means for reading the transmission level corresponding to the signal transmitted to the line from the memory means; Setting means for setting the read out transmission level in the amplification factor setting means, the corresponding transmission level is read out from the memory means prior to signal transmission to the line, and the transmission level read out in the amplification factor setting means is set. It is characterized in that a signal is transmitted after the setting.

Further, in addition to the structure of claim 1, the invention of claim 2 further comprises a comparing means for comparing a transmission signal level of the signal transmitted to the line with a preset threshold value, and the comparison means compares As a result, when the output signal level is higher, the amplification factor set in the amplification factor setting means is lowered by one step and set.

Hereinafter, a detailed description will be given based on an embodiment of the present invention.

1 to 3 are views showing an embodiment of the invention described in claim 1, which is applied to a facsimile apparatus.

In FIG. 1, reference numeral 11 is a facsimile machine, and the facsimile machine 11 includes a main body 12, a document table 13 provided on the top of the main body 12, on which a document is placed, an operating section 14, a handset 15, and the like. The operation unit 14 includes a numeric keypad 14a and operation keys 14b for inputting other commands, and a display unit 14c for displaying input commands and information transmitted from the facsimile device 11 to the operator.
It is set on the installation table 15a provided in 2.

As shown in FIG. 2, the facsimile machine 11 includes a network control unit.
21, a modem 22, a CPU (Central Processing Unit) 23, and the like, and the signals input to the lines L ₁ and L ₂ via the network control unit 21 are amplified by amplifiers 24 and 25.

The network control unit 21 is provided with an isolation transformer 26, the lines L ₁ and L ₂ are connected to the primary side of the transformer 26, and the internal circuit of the facsimile apparatus 11, that is, the amplifiers 24 and 25.
Etc. are connected to the secondary side of the transformer 26. Amplifier 24 has an operational amplifier OP ₁ and resistor R _1, R _2, amplifier 2
Reference numeral 4 amplifies a signal (received signal R _X ) input from the lines L ₁ and L ₂ via the network control unit 21 and outputs it to the modem 22. modem
The signal 22 demodulates the signal input from the amplifier 24 and is also sent to the lines L ₁ and L ₂ via the amplifier 25 (transmission signal T _X ).
To modulate. The amplifier 25 is an operational amplifier OP ₂ , a gain resistor R _A
And a resistor R ₃ .

The gain resistor R _A and the analog switch is used, the resistance data is input to the gain resistor R _A through the data bus 27 from the CPU 23. For the gain resistance R _A, the corresponding switch group is turned on depending on the content of the resistance data from the CPU23.
When turned off, the resistance value of the gain resistor R _A changes.

The CPU 23 outputs a read / write signal to the modem 22 via the control signal line 28, and outputs a command to the modem 22 via the data bus 27 to cause the modem 22 to perform communication control. The CPU 23 has a built-in memory (ROM), and this memory has a built-in basic program as the facsimile apparatus 11, and also has a signal transmission level control program for setting the resistance value of the gain resistor _RA of the present invention. Resistance data is stored. This resistance data is experimentally determined to set the magnitude of the gain resistance R _A corresponding to the amplification factor required in advance for each signal amplified by the amplifier 25.

The CPU 23 and the amplifier 25 constitute a signal transmission level control device 30 as a whole.

Next, the operation will be described.

When transmitting a signal, the facsimile apparatus 11 controls the signal to a transmission level preset for each signal and transmits the signal.

In the following, an example of making a call will be described with reference to the flowchart shown in FIG.

Facsimile apparatus 11 when power is turned on, performs the initialization processing, and outputs a corresponding resistance data transmission level CNG signal (calling tone) to the gain resistor R _A (Step P _1). The gain resistor _RA turns on / off the analog switch based on the resistance data, and sets the resistance value in the RAM 13 (memory means) corresponding to the transmission level of the CNG signal. Thereafter, when the operator inputs a calling request from the operation section 14 (Step P _2), CPU 23 instructs the output of the CNG signal to the modem 22, the modem 22 outputs a CNG signal to the amplifier 25 (Step P _3). The amplifier 25 amplifies the input CNG signal according to the resistance value of the gain resistor R _A set by the above-mentioned data, and sends it to the lines L ₁ and L ₂ via the network control unit 21. When the called station call recognition signal (CED signal, NSF signal, etc.) is input from the other station (step P ₄ ), the CPU 23 causes the resistance data corresponding to the sending level of the DCS signal (digital command signal) to the gain resistance _RA. the output to the gain resistor R _a, a gain resistor R _a is turned analog switch based on the data /
Turn it off and set the resistance to a value corresponding to the DCS signal transmission level (step P _S ). The CPU 23 instructs the modem 22 to set the communication mode also as a calling station and then sends the DCS signal to the modem 22, and the modem 22 amplifies the DCS signal with the amplifier 25, and then the line L via the network control unit 21. ₁ , send to L ₂ (step P ₄ ).

When the other station's modem is ready to receive (step
P _7), CPU 23 outputs a resistance data corresponding to the transmission level of the TCF signal (training check) the gain resistor R _A,
Based on this resistance data, the gain resistance R _A turns on / off the analog switch to set the resistance value to a value corresponding to the TCF signal level (step P ₈ ). CPU23 is TCF to modem 22
Instructing signal output, the modem 22 causes the amplifier 25 to send out a TCF signal (step P ₉ ). When the training signal from the other station is sent (step P _10), CPU 23 has gain resistor resistance data corresponding to the transmission level of the image information signal
Output to R _A (step P ₁₁ ). When the gain resistor R _A adjusts its resistance value based on this resistance data, the CPU 23 instructs the modem 22 to output the image information, and the image information signal from the modem 22 is transmitted to the lines L ₁ and L ₂ via the amplifier 25. It is sent (step P ₁₂ ). When the transmission of the image information is completed, CPU 23 outputs the corresponding resistance data transmission level EOP signal to the gain resistor R _A (End of Procedure signal), gain resistors R _A sets the resistance value based on the resistance data (Step P ₁₃ ). CPU23
Instructs the modem 22 to send the EOP signal, and the modem 22 sends the EOP signal to the lines L ₁ and L ₂ via the amplifier 25 (step P ₁₄ ). When a message confirmation signal from the remote station is sent (step P _15), CPU 23 outputs a resistance data corresponding to the transmission level of the DCN signal (disconnect signal) to the gain resistor R _A, a gain resistor R _A This setting the resistance value based on the resistance data (step P _16). CPU23 DCN to modem 22
After instructing the signal transmission, the network control unit 21 causes the lines L ₁ and L ₂
Disconnect (step P ₁₇ ).

Step _{P 4, P 7, P 10} , when not receiving the normal signals from the partner station in P _15, it is determined that an error, error processing is performed (step P _18).

In this way, the signal sending level control device is configured by reading the corresponding sending level from the RAM 13 prior to sending the signal to the line, setting the read sending level in the gain resistor _RA, and then sending the signal. The transmission level required for various signals can always be stably kept within the regulation value without being affected by the variation of the circuit elements that constitute it.

In the above embodiment, only the operation at the time of transmission has been described, but the signal transmission level can be similarly controlled at the time of reception.

FIGS. 4 and 5 are views showing an embodiment of the invention according to claim 2, and in explaining the present embodiment, the same reference numerals are given to the same components as those of the embodiment shown in FIGS. Is attached and its description is omitted.

FIG. 4 is a diagram showing a main part of the facsimile device 31 according to the present invention. The facsimile device 31 includes a network controller 21 and a modem.
22, amplifier 24, 25, CPU32, register 33, comparator 3
Equipped with 4 and transformer 35.

Similar to the above embodiment, the amplifier 25 uses an analog switch as its gain resistance R _A , and its resistance value changes according to resistance data input from the CPU 32 via the data bus 27.

The transformer 35 has a high impedance and is connected to the lines L ₁ and L ₂ , and its secondary side is connected to the comparator 34.

The comparator 34 includes an operational amplifier OP ₃ and variable resistors VR ₁ and VR ₂ , and is activated when the input signal from the transformer 35 exceeds the threshold value set by the variable resistors VR ₁ and VR _2. Output a signal. The output of the comparator 34 is input to the register 33 via the resistor R ₄ , and the register 33 is set when the output of the comparator 34 becomes an active signal and reset when the output of the modem 22 becomes a non-active signal. The threshold value of the comparator 34 is set to output an active signal when the signal transmitted by the facsimile device 31 approaches the regulation value of the transmission level of the signal at the place where the facsimile device 11 is installed.

The CPU 32 controls each part of the facsimile device 31 according to the program stored in the internal ROM to execute the sequence as the facsimile device 31, and also executes the signal transmission level control process of the present invention. Further, the CPU 32 has a built-in memory and stores control data (resistance data) of the gain resistance _RA .

Next, the operation will be described.

The present invention is characterized in that the output level is controlled in real time during signal transmission. The signal transmission level control process will be described below with reference to the flowchart shown in FIG.

When the power of the facsimile apparatus 31 is turned on, the facsimile apparatus 31 performs an initialization process, and calls the gain resistor R _A with a call signal (in the G3 type,
Outputs resistance data corresponding to the CNG signal) transmission level. (Step S ₁ ).

The resistance value corresponding to this resistance data is set as the resistance value of the gain resistance R _A. When the operator inputs a call request from the operation unit 14 (step S ₂ ), the CPU 32 instructs the modem 22 to output a call signal, and the modem 22 amplifies the call signal by the amplifier 25.
Output (step S _3). The amplifier 25 amplifies the input call signal according to the resistance value of the gain resistor R _A , and the network controller
It is sent to the lines L ₁ and L ₂ via 21. The ringing signal sent to the lines L ₁ and L ₂ passes through the transformer 35 and the comparator 34.
Is input to the comparator 34 and its size is detected by the comparator 34. When the magnitude of the ringing signal becomes larger than the preset threshold value, the comparator 34 outputs an active signal and the register 33 is set. The set / reset of this register 33 CPU 32 are monitored (step S _4). If register 33 is set, CPU32
Judges that the ringing signal is approaching the regulation value, reduces the resistance value of the gain resistor R _A by one step (step S ₁₉ ), and further checks the state of the register 33 (step S ₁₉ ).
S ₂₀ ). This process of adjusting the resistance value of the gain resistor R _A and checking the state of the register 33 are repeated until the register 33 is reset, that is, until the signal becomes stable within the regulation value (steps S ₁₉ , S ₂₀ ).

When the register 33 is reset, the process returns to step S _5, checks the called station identification signal from the remote station (CED signal in G3 type) is input (Step S _5), it is determined that error when not inputted error processing (step S _21).
When the called station identification signal is input (Step S _5), (in the G3 type DCS signal) the calling station communication mode determination signal instructing transmission of the modem 22, the modem 22 is the calling station communication mode determination signal After being amplified by the amplifier 25, the lines L ₁ and L ₂ are transmitted via the network control unit 21.
And it sends (step S _6). Check by the size of the calling station communication mode determination signal starts the state of the register 33 (step S _7), when the register 33 is set, performs a process of adjusting the aforementioned gain resistor R _A ( Steps S ₁₉ , S ₂₀ ).

Then, when the preparation for receiving modem other station is completed (Step S _8), CPU 32 instructs the transmission of modem training signal to the modem 22 (the G3 TCF signal), the modem 22 amplifier 2
The modem training signal is transmitted via 5 (step S ₉ ).

When the training is sent from the partner station (step S
₁₀ ), the CPU 32 instructs the modem 22 to output the image information signal,
The image information signal from the modem 22 is transmitted through the amplifier 25 to the lines L ₁ and L ₂
(Step S ₁₁ ). CPU32 checks by monitoring the state of the size register 33 of the image information signal (step S _12), approaches the regulated value, the process of adjusting the gain resistor R _A (step S _19, S ₂₀₎ .

When the transmission of the image information is completed, the CPU 32 sends the communication end signal (G3
Type, the FOP signal) is sent to the modem 22, and the modem 22
Sends a communication end signal to the lines L ₁ and L ₂ via the amplifier 25 (step S ₁₃ ). Further, the state of the register 33 is monitored so that the level of the communication end signal is within the regulation value (steps S ₁₄ , S ₁₉ , S ₂₀ ). When a message confirmation signal from the remote station come sent (step S _15), it directs the transmission of the modem 22 (DCN signal in G3 type) line disconnection signal, the modem 22 is the line a line disconnection signal through the amplifier 25 It is sent to L ₁ and L ₂ (step S ₁₆ ). The state of the register 33 is monitored and the gain resistance R _A is adjusted so that the level of the line disconnection signal is within the regulation value (steps S ₁₇ , S ₁₉ , S ₂₀ ). The CPU 32 sends the line disconnection signal, and then the network control unit 21 causes the lines L ₁ , L ₂
Is terminated, communication end processing is performed, and this flow ends (step S ₁₈ ). In step _{S 5, S 8, S 10} , S 15, when not receiving the normal signals from the partner station, determines that an error, error processing is performed (step S _21).

In this way, the transmission signal level of the signal transmitted to the line is compared with a preset threshold value by the comparator 34, and when the comparison result shows that the transmission signal level is higher, the amplification factor set in the gain resistor R _A is set. The transmission signal level can be adjusted stepwise by setting the transmission signal level by one step, and the transmission level required for various signals can be obtained without being affected by the variation of the circuit elements that constitute the signal transmission level control device. Can always be kept within the regulation value in a stable manner.

Further, in the above-described embodiment, the case where the invention is applied to the facsimile machine is described, but the invention is not limited to this, and the invention can be applied to a general communication device using a line.

(Effects) According to the inventions of the present application, when various signals are transmitted to a communication partner, the signal is transmitted after setting the transmission level for each signal type to be transmitted. The transmission level required for various signals can always be stably kept within the regulation value without being affected by the variation of the circuit elements constituting the.

[Brief description of drawings]

1 to 3 are diagrams showing an embodiment of a signal transmission level control device of the invention according to claim 1, and FIG. 1 is a perspective view of a facsimile machine to which the signal transmission level control device is applied. FIG. 2 is a circuit diagram of the main part of the facsimile apparatus, and FIG.
The figure is a flow chart showing the signal transmission level control processing during the transmission. 4 and 5 are diagrams showing an embodiment of the signal transmission level control device of the invention according to claim 2, and FIG. 4 is a circuit diagram of a main part of a facsimile apparatus to which the signal transmission level control device is applied, FIG. 5 is a flow chart showing the signal transmission level control processing during the transmission. FIG. 6 is a circuit diagram of a conventional signal transmission level control device. 11 ... Facsimile device, 21 ... Network control unit, 22 ... Modem, 23 ... CPU, 25 ... Amplifier (signal amplification means), _RA ...
... Gain resistance (amplification factor setting means), OP ₂ ... Op-amp, 3
1 ... Facsimile device, 32 ... CPU (reading means, setting means), 33 ... register, 34 ... comparator (comparing means), 35 ... transformer, L ₁ , L ₂ ... line.

Claims (2)

[Scope of utility model registration request] 1. A signal amplification means for amplifying a signal to be transmitted to a line, an amplification factor setting means for variably setting an amplification factor of the signal amplification means, and a transmission required for each signal type transmitted to the line. Memory means for pre-storing the level, reading means for reading the sending level corresponding to the signal sent to the line from the memory means, and setting means for setting the sending level read by the reading means in the amplification factor setting means And transmitting the signal after the corresponding transmission level is read from the memory means before the signal is transmitted to the line and the read transmission level is set in the amplification factor setting means. Signal transmission level control device for controlling. 2. Comprising a comparison means for comparing the transmission signal level of the signal transmitted to the line with a preset threshold value,
As a result of the comparison made by the comparison means, when the transmission signal level is higher, the amplification factor set in the amplification factor setting means is set to 1
2. The signal transmission level control device according to claim 1, wherein the signal transmission level control device is configured so as to be set stepwise.