JPS6318826A - Adjusting system for modem transmission level - Google Patents

Abstract

PURPOSE:To contrive to eliminate troublesome work at the sending level adjustment by using an adjusting transmission signal from a terminal station so as to set automatically the sending level of a MODEM. CONSTITUTION:An adjusting transmission signal from a terminal station is inputted to an input terminal 1 connected to the receiving side of the MODEM 12 and given to the reception side of the MODEM 12 and a peak hold circuit 2. An adder circuit 3 adds a prescribed value to a peak voltage from a peak hold circuit 2 to apply voltage conversion. A decoder circuit 5 forms the D/A conversion function together with a resistor circuit 6 provided at the output side to output a PAM signal. An R conversion control circuit 7 controls a voltage supply to the R conversion circuit 8 based on the PAM signal. Thus, the level of the transmission signal of the MODEM 12 is set and the output voltage of the decoder circuit 5 is held by the latch circuit 9 to fix the level of the transmission signal of the MODEM 12.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a modem transmission level adjustment method.

(Prior Art) Conventionally, the transmission level of a modem has been adjusted as follows. First, the level to be set is confirmed by checking the level of the information from the terminal station or the adjustment transmission signal from the terminal station6.Then, in order to set it to that level, the attenuator installed on the transmitting side inside the modem housing is used. Switching was done by soldering the strap wire, or by switching the attenuator switch installed on the back of the housing.

(Problems to be Solved by the Invention) However, the conventional method described above requires manual work such as soldering the attenuator strap wire and switching switches in order to adjust the output level of the modem, resulting in cumbersome work. Ta.

The present invention is intended to solve these problems, and aims to eliminate the hassle of adjusting the output level by automatically setting the output level of the modem using the adjustment output signal from the terminal station. shall be.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a resistor provided on the transmitting side of the modem based on the level of the adjustment sending signal from the terminal station received on the receiving side of the modem. In a modem output level adjustment method that adjusts the level of the output signal to the terminal station by varying the resistance value, the modem output level adjustment method holds the peak value of the level of the adjustment output signal from the terminal station and outputs the peak voltage. 1 means, a second means for converting the peak voltage from the first means into a digital signal, a third means for converting the digital signal from the second means into a PAM signal, and a resistor; a fourth means for dividing the level of the signal sent to the terminal station by a resistance provided on the transmitting side by varying the internal resistance value based on the voltage of the PAM signal from the third means; and fifth means for maintaining the level of the signal sent to the terminal station divided by the voltage.

(Function) According to the present invention having the above configuration, the first means holds the peak value of the level of the adjustment sending signal from the terminal station and outputs the peak voltage.

The peak voltage is then converted into a digital signal by the second means.

Furthermore, the digital signal is converted into a PAM signal by third means. The fourth means adjusts the level of the signal sent to the terminal station by varying the internal resistance value based on the voltage of the PAM signal, thereby changing the voltage division with the resistor provided on the transmitting side of the modem. Further, the fifth means maintains the adjusted level of the signal sent to the terminal station.

Therefore, the present invention can solve the above-mentioned problems and provide a modem output level adjustment method that can eliminate the hassle of adjusting the output level.

(Example) Hereinafter, one embodiment of the present invention will be described based on the drawings.

The accompanying drawings are block diagrams illustrating one embodiment of the present invention.

In the figure, 1 is a telephone line from a terminal station (not shown);
An input terminal into which a transmission signal such as an adjustment transmission signal is input via a 2-wire to 4-wire converter circuit, 2 holds the peak level of the adjustment transmission signal input from input terminal 1 to calculate the peak voltage. 3 is an adder circuit that adds a predetermined value to the peak voltage to convert the voltage; 4 is an A/V converter that converts the peak voltage into a digital signal;
A D conversion circuit, 5 is a decoder circuit that forms a D/A conversion function together with a resistance circuit 6 provided on the output side and will be described later, and converts a digital signal from the A/D conversion circuit 4 into a PAM signal, and 6 is a resistance circuit. , 7 is an R conversion control circuit that controls voltage supply to an R conversion circuit 8 (described later) based on a PAM signal from a decoder circuit 5 and a resistor circuit 6, and 8 is a resistor 1 (described later).
an R conversion circuit 9 connected to 0 and whose internal resistance changes depending on the voltage supplied from the R conversion control circuit 7 to adjust the level of a signal sent out from the modem 12, which will be described later, by dividing the voltage with the resistor 10;
10 is a latch circuit that holds the output voltage of the decoder circuit 5 and fixes the level of the signal sent to the output terminal 11 (described later) at the level after completion of adjustment; 10 is a resistor connected to the transmitting side of the modem 12 (described later); 11 is an output terminal, and 12 is a modem. Here, the decoder circuit 5 includes, for example, 4 of the CMO 8.
515, and for the R conversion circuit 8, for example, an FET is used.

Next, the operation of this embodiment will be explained using the accompanying drawings.

An adjustment transmission signal from a terminal station is input to an input terminal 1 connected to the receiving side of the modem 12. This adjustment sending signal is supplied to the receiving side of the modem 12 and the peak hold circuit 2. The peak hold circuit 2 holds the peak value of the level of the adjustment sending signal and outputs a peak voltage. Then, the adder circuit 3 adds a predetermined value to the peak voltage from the peak hold circuit 2 to perform voltage conversion. In the A/D conversion circuit 4, the peak voltage converted by the addition circuit 3 is converted into a digital signal, and the digital signal is supplied to the next decoder circuit 5. The decoder circuit 5 forms a D/A conversion function together with a resistor circuit 6 provided on the output side, and outputs a PAM signal. The R conversion control circuit 7 controls the voltage supply to the R conversion circuit 8 based on the PAM signal. In the R conversion circuit 8, the internal resistance changes according to voltage supply control by the R conversion control circuit 7. Therefore, the level of the signal sent out by the modem 12 is
The voltage is divided by the R conversion circuit 8 and sent to the output terminal 11.

Further, after the level of the signal sent out from the modem 12 is set, the output voltage of the decoder circuit 5 is held by the latch circuit 9, and the level of the signal sent out from the modem 12 is fixed.

(Effects of the Invention) As explained above, according to the present invention, the troublesome work of adjusting the output level is eliminated by automatically setting the output level of the modem using the adjustment output signal from the terminal station. It is possible to provide a method for adjusting the modem output level.

[Brief explanation of the drawing]

The accompanying drawings are block diagrams illustrating one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Input terminal, 2...Peak hold circuit, 3...Addition circuit, 4...A/D conversion circuit, 5...Decoder circuit, 6...Resistance circuit, 7
...R conversion control circuit, 8...R conversion circuit, 9...
・Latch circuit, 10...Resistor, 11...Output terminal, 12...Modem.

Claims (1)

[Claims] By varying the resistance value of a resistor provided on the transmitting side of the modem based on the level of the adjustment transmitting signal from the terminal station received on the receiving side of the modem, the output signal to the terminal station can be adjusted. A modem output level adjustment method for adjusting a level, comprising: a first means for holding a peak value of a level of an adjustment output signal from a terminal station and outputting a peak voltage; and the peak voltage from the first means. second means for converting the digital signal from the second means into a PAM signal; and third means for converting the digital signal from the second means into a PAM signal; a fourth means for dividing the level of the signal sent to the terminal station by the resistor by varying the internal resistance value based on the voltage of the fourth means; and the signal sent to the terminal station divided by the fourth means. and fifth means for maintaining the level of the modem.