JPH03226036A - Signal transmission system - Google Patents

Abstract

PURPOSE:To attain the phase locked loop frequency control for a reception end by transferring input signal interruption detection signal information of a sending end synchronization conversion circuit to the reception end through the use of an idle time slot. CONSTITUTION:When an NRZ signal 2 is interrupted, the input signal interruption detection circuit 103 detects the interruption of the NRZ signal to send an information signal 3A representing the input signal interruption to a sending end multiplex conversion circuit 20. The sending end multiplex conversion circuit 20 inserts the information signal 3A to a predetermined idle time slot and outputs the resulting signal as a multiplex signal 10. A reception end isolation circuit 21 detects an input signal interruption detection signal 18 being the input signal interruption through a prescribed time slot and sends it to a reception end synchronization conversion circuit 22. In receiving the input signal interruption detection signal 18, the phase locked loop frequency of the reception end synchronization conversion circuit 22 is locked and the standby state is held till the input signal is again in operation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a signal transmission method, and in particular, in wireless digital transmission in which multiple columns of input signals are transmitted using a stuffing phase synchronization method, even when the input signal is disconnected, the present invention relates to a signal transmission method. The present invention relates to a signal transmission method that allows frequency control of a face-locked loop to be continued at the receiving end and also allows the receiving end to recognize the normality of a wireless transmission path.

[Conventional technology]

Conventionally, this type of signal transmission system consists of a sending end side at the top of the figure and a receiving end side at the bottom, as shown in the configuration diagram in Figure 2.The sending end side has multiple rows of equipment interfaces ( A sending end interface circuit 101 inputs a bipolar (bipolar) signal 1 and converts it into an NRZ signal 2 suitable for wireless transmission and logic processing. A sending-end interperiod conversion circuit 102 outputs a super frame pulse 18 that maintains frame synchronization with stuffing information 5 that leaves the pulse stuffing information of the signal, and converts the auxiliary signal 7 in addition to the synchronous conversion signal 9 and the frame synchronization signal 8 into a super frame. A sending-end multiplex conversion circuit 106 inserts a pulse 18 into the pulse array of each frame and outputs a multiplexed signal 10.
, an input signal disconnection detection circuit 103 that detects disconnection of the NRZ signal 2 and outputs a switching signal 3, and generates a fixed stuffing signal 4 whose stuffing rate is close to that of the stuffed synchronous conversion signal 9 of multiple columns and whose pulse stuffing is fixed. It is composed of a soot fixed stuffing generation circuit 104 and a changeover switch 105 that switches a switch connected to the stuffing signal 5 side in normal times to the fixed stuffing signal 4 side in response to the changeover signal 3.

The receiving end receives the multiplexed signal 10 and sends it to the frame synchronization circuit 1.
At step 08, a frame synchronization signal 14 equivalent to the frame synchronization signal 8 on the sending end side is detected, and the receiving end separation separates and outputs the synchronization conversion signal 11, auxiliary signal 12, and stuffing information 13 using this frame synchronization signal 14. The conversion circuit 107 is paired with the sending end synchronous conversion circuit 102, performs phase-lock loop frequency control on the stuffed synchronous conversion signal 11 based on stuffing information 13, and smoothes the synchronous conversion signal 11 with a phase gap. A receiving end synchronous conversion circuit 109 outputs a clock signal 16 synchronized with the input signal and an NRZ signal 15 corresponding to the NRZ signal 2 on the sending end, and a receiving end synchronous conversion circuit 109 outputs a clock signal 16 synchronized with the input signal and an NRZ signal 15 corresponding to the sending end side NRZ signal 2, and a receiving end synchronous conversion circuit 109 outputs a clock signal 16 synchronized with the input signal and an NRZ signal 15 corresponding to the sending end side NRZ signal 2.
It consists of a receiving end interface circuit 110 that outputs a bipolar) signal 17. Here, when the input signal disconnection detection circuit 103 on the sending end side detects an input signal disconnection and switches to the fixed stuffing signal 4 and sends it to the receiving end side, phase-locked loop frequency control is performed using this fixed stuffing signal. , synchronization between the transmitting and receiving synchronous conversion signals 9 and 11 was ensured.

[Problem to be solved by the invention]

However, in the conventional signal transmission system described above, when the input signal to the sending end synchronous conversion circuit is interrupted, the receiving end face-locked loop frequency control is performed using fixed stuffing control. This has the disadvantage that the configuration of the fixed stuffing information generation circuit for generating a similar fixed stuffing ratio is complicated.

[Means to solve the problem]

The signal transmission method of the present invention is a signal transmission method in which a plurality of input signals are transmitted from a sending end to a receiving end, and the input signals are phase-synchronized by a stuffing method. It has means for transmitting the signal from the end side to the receiving end side and controlling the frequency of the phase-locked loop on the receiving end side.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, circuits with the same numbers as in FIG. 2 of the conventional example perform the same operations as the conventional circuits. Therefore, the transmitting-end multiplex conversion circuit 20, the receiving-end separation conversion circuit 21, and the receiving-end synchronous conversion circuit 22 improved in this embodiment will be mainly explained.

First, when multiple columns of NRZ signals 2 are normally output, the sending end multiplex conversion diagram i20 inputs the stuffed synchronization conversion signal 9, stuffing information 5, auxiliary signal 7, and frame synchronization signal 8, A multiplexed signal 10 is output by arranging the respective signals in pulse time slots within each frame. On the receiving side, a receiving end separation conversion circuit 21 outputs a synchronous conversion signal 11, an auxiliary signal 12, and stuffing information 13. Receiving end synchronous conversion circuit 2
2 performs phase-locked loop frequency control based on the stuffing information 13, and outputs the same clock signal 16 and NRZ signal 15 as on the sending end side, as in the conventional example. Then N
When the RZ signal 2 is disconnected, the input signal disconnection detection port 103 detects the disconnection of the NRZ signal and sends the input signal disconnection information signal 3A to the sending end multiplex conversion circuit 20. The sending end multiplex conversion circuit 20 inserts this information signal 3A into a predetermined vacant time slot and outputs it as a multiplexed signal 10. The receiving end separation circuit 21 detects the input signal disconnection detection signal 18, which is information about the input signal disconnection, from a predetermined time slot and sends it to the receiving end synchronization conversion circuit 22. When the receiving end synchronization conversion circuit 22 receives this input signal disconnection detection signal 18, the face lock loop frequency is locked and the standby state is maintained until the input signal starts operating again. As described above, the operation of phase-locked loop frequency control can be continued even when the input signal is cut off, without requiring a fixed stuffing signal set separately as in the conventional example.

〔Effect of the invention〕

As described above, the present invention can perform phase-locked loop frequency control at the receiving end by transferring the input signal disconnection detection signal information of the sending end synchronous conversion circuit to the receiving end using an empty time slot. . Therefore, it is possible to perform phase-locked loop frequency control at the receiving end without providing a complicated fixed stuffing information generation circuit for generating a fixed stuffing rate close to the stuffing rate determined in a conventional system. can get.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional signal transmission system. 20.106... Sending end multiplex conversion circuit, 21.107.
...Receiving end separation conversion circuit, 22,109...Receiving end synchronous conversion circuit, 101...Sending end interface conversion circuit,
102... Transmission end synchronization conversion circuit, 103... Input signal disconnection detection circuit, 104... Fixed stuffing information generation circuit, 105... Changeover switch, 108... Frame synchronization circuit, 110... Reception End interface conversion circuit.

Claims (1)

[Claims] 1. In a signal transmission method in which a plurality of strings of input signals are transmitted from a sending end to a receiving end and the input signals are phase synchronized by a stuffing method, the detection information of the input signal disconnection is transmitted. A signal transmission method characterized by having means for transmitting from an end side to a receiving end side and controlling the frequency of a phase-locked loop on the receiving end side. 2. A transmitting-end multiplex conversion circuit that inserts the input signal disconnection detection information into a time slot in a predetermined frame, and a phase lock that receives the detection information and operates based on stuffing information at the receiving end. 2. The signal transmission system according to claim 1, further comprising a receiving end synchronous conversion circuit that continues the frequency control state of the loop.