JPS60117840A - Output level adjusting system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (4) Technical Field of the Invention The present invention relates to output level adjustment, and in particular to α between a network termination used in a so-called information network system (INS) and each terminal.
) This relates to an output level adjustment method for adjusting the output level so that the channels associated with each terminal are output at the correct output level in frame information used for communication.

(B) Technical background and problems Recently, the so-called INS concept has been considered, and the uplink (T line) and downlink # (R#) are wired from the network termination seal, and 4! r type of terminal (terminal equipment)
is configured to communicate with the network termination using the channel in the frame information on the T line or R line, and the network termination functions as a transmission intermediary function device between the external line and the various terminals. Consideration is given to making them work.

Figure 1 shows the connection between the network termination and each terminal, Figure 2 (A) shows the conventional 7 frame information on the R@ line, and Figure 2 (B) shows the conventional frame information on the T line. It shows.

In Figure 1, 1 is the network termination,
2 is an external line, 3 is an R line (down line), 4 is a T line (up line), 5-1. ...5-N represents the terminal 11%
Terminal 5-1. ...5-N is an arbitrary distance MItx from network termination 1.

...It is installed at tN so that its position can be changed. Then, network termination 1 is shown in Figure 2 (
A) As shown in the figure, frame information having a frame synchronization signal F and a plurality of channels CH1, CH2, etc. is sent on the tR line, while each terminal, for example 5-1, receives the frame synchronization signal F based on the fact that it has received the frame synchronization signal F. As shown in FIG. 2(B), it operates to place information on the channel CHj at the timing of the channel j assigned to itself. In other words, the network termination 1 is configured to detect frame information as shown in FIG. 2(B) being transmitted on the T line.

In the conventional mode as described above, each terminal 5 is installed at a distance t1. from the network termination l.・・・
... are different, so if each terminal carries information on its own assigned channel CH, the multiplexed frame information received at the reception point of network termination 1 will be As shown in Figure 3, the amplitude differs depending on the channel, and when trying to identify the above frame information using a fixed threshold in network termination 1, it is difficult to set the threshold, and in some cases it may be impossible to set an appropriate threshold. Sometimes it's possible.

If the above fixed threshold is set according to the level of information from the terminal farthest from the network termination, the threshold will be unnecessarily too low for the level of information from the nearest terminal, and noise superimposed on the signal will be trapped. There is a risk that it will happen. AGC (Automatic Galn Control) has traditionally been used as a receiving circuit that can respond to changes in input signal level.
t) Circuits and ATC (Automatic Thr@gh
otdControl) circuits, but these are effective when the time constant of the input signal level change is large, but it is difficult to apply them to the case where the time constant is short such that the level changes within the same frame as described above. This has traditionally been addressed by fixed thresholds and by placing certain limits on the distance of the farthest terminal from the network termination. On the other hand, from the standpoint of a user using a terminal, such distance restrictions that impose restrictions on the wiring configuration of the terminal are not desirable.

(Q. Purpose and structure of the invention ゛The present invention aims to solve the above points, and the output level adjustment method of the present invention includes a network infrastructure 1 connected to an external line. and a plurality of terminals branched to a common uplink and downlink for the network termination, and communication between each terminal and the network termination is connected to the uplink and the downlink. In a communication system configured to perform communication using a channel on frame information carried on the downlink, each terminal has an uplink monitor in response to a predetermined timing in the frame information on the uplink. - An uplink monitor pattern insertion mechanism that inserts a pattern into the network; a downlink monitor button that detects a downlink monitor button that causes the uplink monitor pattern to be looped back at a predetermined timing in the frame information on the downlink at termination; A line monitor pattern detection mechanism and an output level adjustment mechanism for adjusting the output level of information output on the uplink are provided, and the uplink monitor pattern inserted from the own terminal is the same as the downlink monitor pattern. The present invention is characterized in that the output level in the output level adjustment mechanism is adjusted to ensure accurate detection.This will be explained below with reference to the drawings.

0 Embodiment of the Invention FIG. 4 shows the configuration of an embodiment of the present invention, FIG. 5(A) shows frame information of an embodiment on the R line, and FIG. 5(B) shows frame information of an embodiment on the T line. shows.

Further, FIG. 6 is a configuration example of the network termination shown in FIG. 4, FIG. 7 is a time chart illustrating an aspect of folding back the monitor pattern referred to in the present invention in the configuration shown in FIG. 6, and FIG. #! 4 shows an embodiment of the configuration of the terminal shown in FIG.

In FIG. 4, numerals 1, 2.3, and 4.5 correspond to those in FIG. 1, 6 is an uplink monitor/bum insertion mechanism, 7 is a downlink monitor/pattern detection mechanism, 8 is an output level adjustment mechanism, and 9
represents the monitor pattern wrapping mechanism.

In the case of the present invention, in order to reduce the difference in network termination reception level depending on the installation position of each terminal,
-1 is provided with an output level adjuster #18 so that the output level adjuster 8 can be adjusted so that the output level from each terminal has a constant amplitude at the network termination receiving point. This specific method will be explained below.

The threshold of the amplifier circuit at the network termination is set in advance to 1/2 of the input level from the farthest terminal. First, place the terminal you want to adjust at the monitor/button insertion position MTK″0″ in Figure 5(B).
and send it to the T line. Network termination 1 receives this and returns it to the R line as MR.
At this time, MR is naturally folded back as uO++. Next, the terminal increases the signal level by a small amount ΔV and sends it to the T line (by the output level adjustment mechanism). At network termination, loop back as before.

Repeating this operation, the MR on the R line at the terminal
Check the number of times the output level increases until it reaches 1°' for the first time. If this were the 2nd round, the final 111th
``Assume that the output level of the code is an amplitude corresponding to the number of increases equal to 2 times (Vout (1) = 2K・ΔV). I I means that the I+ code output level has been adjusted to be received at the network termination receiving point as an amplitude twice the threshold of the receiver of the network number termination, which satisfies the above requirement.

FIG. 6 shows an embodiment of the configuration of the portion that loops back to the MR on the MTeR line on the T line in the network termination, and FIG. 7 shows its time chart. When frame information is input from the T line 4, it is first identified by the receiver 11 having the above-mentioned fixed threshold.
), and at the same time the monitor pattern MT is latched by the flip-flop 12 and inputted into the selector 1401 manually.

The other input of the selector 14 is received multiplexing information as shown in FIG. 7(D), and the MT and receiving multiplexing information are selected by the selection signal as shown in FIG. 7(E), and the MT is used as an MR. Turn back to R line. (FIG. 7F) FIG. 8 shows the configuration of an embodiment of the terminal of the present invention. When frame information is input from the R line, it is first identified by a normal receiver circuit 21, a clock is extracted by a PLL 22, and the frame information is reproduced by a flip-flop 23 using the clock. The reproduced frame information is subjected to frame synchronization by the frame synchronization circuit 24 and is taken into the terminal as received information. On the other hand, the clock circuit 25 uses the clock signal from the PLL 22 and the frame synchronization signal from the frame synchronization circuit 24 to generate a constant 1IIll1111 clock for the entire circuit.

The flip 7a knob 26 extracts the monitor pattern MRk from the received frame information and launches it.

Counter 28, ROM 30, flip-flop 29,
The latch 31 and selector 32 are circuits for controlling the output level adjustment circuit 34. The eROM 30 is a circuit for controlling the output level adjustment circuit 34.
Starting from address O, the output level increases by ΔV every time the address increases by 1 on the a side.
On the other hand, data is written to perform switch control such that the output level increases by 2.ΔV every time the address increases by 1. 0 Honji has a.

Switch control data is written such that the output level is O for both of the switches (b). Further, the selector 33 is for selecting the transmission multiplexing information and the transmission monitor pattern M'T. The output level adjustment circuit 34 is composed of a variable amplifier using an operational amplifier, and is connected to the switches 14-1.・・・・・・
...The gain is adjusted by 14-mk control. The operation of the valley part when adjusting the output level is as follows.

In the initial state of output level adjustment, the counter 28 and flip-flop 29 are reset and the selector 32 is set to a II.
I have selected I. Therefore, 0 is sent to the first MT. This is turned back as MR at the network termination and latched by the slip/70 block 26. If the result is 0, the NOR gate 27 passes the entire clock and increments the counter 28. As a result, the ROM 30 outputs switch control data such that the output level increases by ΔV, and the next MT becomes Δ■. The above operation is repeated, for example, the 7th rip-flop 26
When the output MR of becomes 1 for the first time, the counter 28 is completely inhibited from stepping, and the latch 31 is
30 is latched, the flip-flop 29 is set, and the selector 32 is controlled to select b' Oil. The switch control data b' at this time is such that the output level is 2K·ΔV, and the output level is thereafter fixed at this value and the output level adjustment is completed.

[F] Effects of the Invention According to the present invention, receiver rotation at network termination can be realized using a fixed threshold method with a simple configuration, and the distance between the network termination and the terminal can be kept sufficiently large. This has the effect of providing flexibility in the wiring configuration of user terminals.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams for explaining conventional aspects, FIG. 4 shows the configuration of an embodiment of the present invention, and FIG. 5(A) shows frame information of an embodiment on the R line; B) shows one example frame information on the T line. FIG. 6 shows the configuration of an embodiment of the network termination shown in FIG. 4, and FIG.
FIG. 8 is a time chart illustrating an aspect of folding back the monitor pattern referred to in the present invention in the illustrated configuration, and FIG. 8 shows an embodiment of the configuration of the terminal illustrated in FIG. 4.

Claims (1)

[Claims] It comprises a network termination code connected to an external line, and a plurality of terminals branched to a common uplink line and a downlink line for the network termination code, and each of the terminals and In a communication system configured such that communication with the network termination is performed using a channel on frame information carried on the uplink and downlink, in each of the terminals, an uplink monitor pattern insertion AIIS for inserting an uplink monitor e pattern corresponding to a predetermined timing in the frame information on the downlink at the network termination; A down line monitor pattern detection mechanism for detecting a down line monitor pattern that has been sent back, and an output level adjustment mechanism for adjusting the output level of the information output on the up line are provided, The uplink monitor pattern is the downlink monitor Φ1-7'!
: L, -''c Reluctant I2 Down 6' / An output level adjustment method characterized in that the output level in a coil adjustment mechanism is adjusted.