JPH088632B2 - Facsimile device transceiver - Google Patents

Description

The present invention relates to a transmitting / receiving device of a facsimile machine.

[Prior Art] Generally, in a communication device such as a facsimile machine that transmits and receives image signals, data, and the like through an analog line such as a telephone line, communication with a partner station connected through the analog line is performed. A transmitter / receiver for transmitting / receiving a signal by using a modulator / demodulator is incorporated therein.

In this type of conventional transmitter / receiver, an equalizer (equalizer) for compensating the frequency characteristics of the transmission / reception signal and an attenuator (ATT) for attenuating the transmission level of the transmission signal
Is provided. Then, when the communication device incorporating the transmitting / receiving device is attached to the user side, the maker side sets the frequency characteristic of the equalizer and the attenuation rate of the attenuator based on the installation condition.

[Problems to be Solved by the Invention] However, the equalizer and the attenuator used in the conventional transmitter / receiver of this kind have a predetermined constant value irrespective of the deterioration of the signal due to the distance of the line or the obstacle. In order to compensate and attenuate the transmitted / received signal, the degree of signal deterioration always changes depending on the distance of the line with the partner station and the presence / absence of a failure, but such a change in signal level cannot be dealt with. For this reason, the compensating action by the equalizer and the attenuating action by the attenuator sometimes cause deterioration of signal communication quality.

Therefore, the present invention variably adjusts the compensation value of the transmission equalizer and the attenuation rate of the attenuator at the time of image signal transmission, and the compensation value of the reception equalizer at the time of image signal reception, according to the signal level of the reception signal from the partner station. Therefore, it is an object of the present invention to provide a transceiver device of a facsimile machine capable of improving the signal communication quality by appropriately responding to the change of the signal level due to the distance of the line with the partner station and the presence / absence of a failure.

[Means for Solving the Problem] The present invention relates to a facsimile device that transmits and receives an image signal and the like to and from a partner station connected via a line, using a signal received by the modulator and demodulator. A reception equalizer for compensating the frequency characteristic of, and a transmission equalizer for compensating the frequency characteristic of the signal transmitted from the modulator / demodulator,
If the line between the attenuator that attenuates the signal level of the signal transmitted from the modulator / demodulator and the other station is connected prior to the transmission of the image signal, the reception level of the signal from this other station is detected multiple times. The reception average level calculation means for calculating the average level of the reception level at the time of transmission, the reception signal average level calculated by this calculation means and the preset reference signal level at the time of transmission are compared, and the present of the transmission equalizer is compared. Of the compensation value and the current attenuation rate of the attenuator, and a transmission level for resetting the compensation value of the transmission equalizer and the attenuation rate of the attenuator to optimum values based on the evaluation result by the evaluation means. When the adjusting means and the line with the partner station are connected prior to receiving the image signal, the reception level of the signal from this partner station is detected multiple times and the average level of the multiple reception levels is detected. A reception average level calculating means for calculating the reception equalization level and a reception signal average level calculated by the calculation means are compared with a preset reference signal level at reception to evaluate the current compensation value of the reception equalizer. The time evaluation means and the reception level adjustment means for resetting the compensation value of the reception equalizer to the optimum value based on the evaluation result by this evaluation means.

[Operation] With the transmission / reception device having such means, if the reception level of the signal from the partner station is lower than the reference signal level at the time of signal transmission, the distance to the partner station is long or there is a failure. Since it is predicted that the signal has deteriorated, the optimum transmission level can be obtained by automatically adjusting the equalizer, attenuator, etc. of the transmission system. Also, even when receiving a signal, if the reception level of the signal from the partner station is smaller than the reference reception level, it is predicted that the signal is deteriorated because the distance to the partner station is long or there is a failure. The optimum reception level can be obtained by automatically adjusting the equalizer of the system.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the apparatus of this embodiment,
A CPU (central processing unit) 1 as a main body of a control unit has a ROM (Read Only Memory) that stores program data for the CPU 1 to control each unit via a bus line 2.
Memory) 3, a RAM (Random Accum Memory) 4 in which various memories used by the CPU 1 to control each part are formed, a telephone circuit 7 connected to a handset 5 and a speaker 6 of a telephone, an image signal, A modem (modulator / demodulator) 8 that modulates and demodulates data and the like, and an I / O port 9 that outputs an adjustment signal to a reception equalizer 15, a transmission filter 16, and a transmission equalizer 17, which will be described later, according to a designation from the CPU 1 are connected. .

Further, the CPU 1 controls the line switching processing in the line switching relay 10. The line switching relay 10 switches the telephone line 11 to the telephone circuit side or the modem side in response to a control command from the CPU 1, and normally the telephone circuit side is selected. The telephone circuit 7 is directly connected to the telephone circuit side of the line switching relay 10 and the telephone circuit 7 is connected to the telephone line 11.
When a calling signal is input from the other station via the line switching relay 10, it is detected and the CPU 1 is notified.

On the other hand, a matching transformer 12 and a 2-wire to 4-wire conversion circuit 13 are connected in series on the modem side of the line switching relay 10, and a series circuit of a reception filter 14 and a reception equalizer 15 as a reception system and a transmission circuit. A modem 8 is connected in parallel with a series circuit of a transmission filter 16 and a transmission equalizer 17 as a system. Where the transmit filter 16
An attenuator (ATT) is incorporated in the transmission filter 16, and the attenuation factor of the attenuator in the transmission filter 16 and the reception equalizer 15 are included.
Each compensation value of the transmission equalizer 17 and the transmission equalizer 17 is variable by the adjustment signal output from the I / O port 9.

In the transmission / reception apparatus having such a configuration, the CPU 1 is program-controlled so as to execute the processing shown in the flowchart of FIG. 2 when transmitting an image signal or data. That is, when the telephone number is input from the telephone, it dials to the partner station via the telephone circuit 7, the line switching relay 10 and the telephone line 11. Then, when the line with the partner station is connected, the line switching relay 10 is switched to the modem side to match the response signal from the partner station with the matching transformer 12, the 2-wire to 4-wire conversion circuit 13, the reception filter 14 and the reception equalizer 15. Through the modem 8
Give to. Next, the AGC (automatic gain control) data in the modem 8 is sampled to measure the reception level of the response signal from the partner station, and temporarily stored in the RAM 4. This AG
R by repeating sampling of C data multiple times
If a predetermined number of reception level data is accumulated in AM4,
The accumulated data is taken out and the average level of the received signal is calculated. Then, the calculated received signal average level is compared with a preset reference signal level to predict the signal deterioration state due to the distance of the line to the partner station or a failure, and based on the prediction result. Evaluate the current compensation value of the transmit equalizer 17. If the current compensation value is inappropriate, the I / O port 9 outputs a desired adjustment signal to the transmission equalizer 17 to reset the compensation value.

Specifically, the reference signal level is set in a plurality of steps, and the optimum compensation value in the transmission equalizer 17 is set for each reference signal level. The optimum compensation value for each reference signal level can be changed by using an input means such as a keyboard (not shown). Then, it is checked which stage of the reference signal level the consultation signal average level corresponds to, and the compensation value for the corresponding reference signal level is compared with the current compensation value in the transmission equalizer 17. If they match, the compensation value is recognized as not appropriate and the compensation value is not changed. If they do not match, the compensation value is recognized as inappropriate and the compensation value for the corresponding reference signal level is changed.

Further, the present attenuation rate of the attenuator in the transmission filter 16 is evaluated in the same manner as in the case of the compensation value for the transmission equalizer 17 based on the above-mentioned prediction result of the signal deterioration state, and if inappropriate, the I / O port 9 A desired adjustment signal is output to the transmission filter 16 to reset the attenuation rate. Then, the transmission of both signals or data is started via the modem 8.

On the other hand, when receiving an image signal or data, the CPU 1 is program-controlled so as to execute the processing shown in the flowchart of FIG. That is, when the input of the calling signal is notified from the telephone circuit 7, the line switching relay 10 is switched to the modem side, and the signal from the partner station is matched with the matching transformers 12,2.
It is given to the modem 8 through the line-to-four line conversion circuit 13, the reception filter 14 and the reception equalizer 15. Then, as in the case of transmission, the AGC data in the modem 8 is sampled a plurality of times to calculate the average level of the reception signal from the partner station, and this reception signal average level is compared with the preset reference signal level. Then, the deterioration state of the signal due to the distance of the line to the partner station or the obstacle is predicted. Next, the current compensation value of the reception equalizer 15 is evaluated based on the prediction result, and if the current compensation value is inappropriate, the I / O port 9 outputs a desired adjustment signal to the reception equalizer 15. Reset the compensation value. Then, the reception of image signals or data is started via the modem 8.

As described above, in the transmission / reception device of the present embodiment, when transmitting / receiving the image signal or data, the deterioration state is predicted in the signal caused by the line distance or the failure according to the level of the reception signal from the partner station, and the prediction result is obtained. By automatically adjusting the frequency compensation value in the transmission equalizer 17 and the reception equalizer 15 and the attenuation factor of the attenuator in the transmission filter 16 based on the above, the level correction of the transmission / reception signal can always be performed optimally. For example, if the distance from the partner transmitting station is short at the time of reception and the deterioration of the signal is predicted to be small, the compensation value of the reception equalizer 15 is lowered. By doing so, the received signal can be obtained with optimum frequency characteristics. Further, when it is predicted that the distance from the receiving station at the other end is large at the time of transmission and the deterioration of the signal is large, the compensation value of the transmission equalizer 17 is increased and the attenuation rate of the attenuator in the transmission filter 16 is decreased.
By doing so, the signal can be transmitted at the optimum output level.

Therefore, the image signal or data can always be transmitted to the communication partner in the optimum state, and the image signal or data from the partner station can always be received in the optimum state, so that the signal communication quality can be improved. . Further, since the compensation value of the reception equalizer 15 and the transmission equalizer 17 and the attenuation rate of the attenuator are automatically adjusted, it is possible to install a communication device such as a facsimile machine in which the transceiver device of this embodiment is installed on the user side. In addition, it is not necessary for the manufacturer to adjust the compensation value and the attenuation rate.

It should be noted that although the case where communication is performed using the telephone line 11 is shown in the above-described embodiment, the present invention can be applied even to a transmitting / receiving device that performs communication using an analog line other than the telephone line. Of course.

[Effects of the Invention] As described in detail above, according to the present invention, the signal level of the received signal from the partner station can be accurately detected, and the compensation value of the transmission equalizer and The attenuation factor of the attenuator can be variably adjusted to the optimum value of the compensation value of the reception equalizer when receiving the image signal, and the signal communication can be performed accurately in response to the change in the signal level depending on the distance between the partner station and the line It is possible to provide a transmission / reception device of a facsimile device capable of improving quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a flow chart showing a transmitting operation, and FIG. 3 is a flow chart showing a receiving operation. 1 ... CPU, 7 ... Telephone circuit, 8 ... Modem (modulator / demodulator), 10 ... Line switching relay, 14 ... Reception filter, 15
…… Receive equalizer, 16 …… Transmit filter, 17 …… Transmit equalizer.

Claims (1)

[Claims] 1. A facsimile apparatus for transmitting and receiving an image signal and the like to and from a partner station connected via a line by using a modulation / demodulation apparatus, wherein reception is performed to compensate for frequency characteristics of a signal received by the modulation / demodulation apparatus. An equalizer, a transmission equalizer for compensating the frequency characteristic of the signal transmitted from the modulation / demodulation device, an attenuator for attenuating the signal level of the signal transmitted from the modulation / demodulation device, and the other station prior to the transmission of the image signal When the line is connected, the reception level of the signal from the partner station is detected a plurality of times and the average level of the reception levels of the plurality of times is calculated, and the reception average level calculation means for calculating the reception level at the time of transmission. The signal average level is compared with a preset reference signal level during transmission to evaluate the current compensation value of the transmission equalizer and the current attenuation rate of the attenuator. And a transmitting level adjusting means for resetting the compensation value of the transmitting equalizer and the attenuation rate of the attenuator to optimum values based on the evaluation result by the evaluating means, and for receiving the image signal. When the line with the partner station is connected in advance, a reception average reception level calculating means for detecting the reception level of the signal from the partner station a plurality of times and calculating an average level of the reception levels of the plurality of times, and this calculation A reception time evaluation means for evaluating the current compensation value of the reception equalizer by comparing the reception signal average level calculated by the means with a preset reference signal level at the time of reception, and based on the evaluation result by the evaluation means. And a reception level adjusting means for resetting the compensation value of the reception equalizer to an optimum value.