Pointer processing circuit in sonet system
First Claim
1. A pointer processing circuit in combination with a cross connect equipment in a SONET transmission system which has said cross connect equipment between a reception part and a transmission part, and a frame counter connected to said pointer processing circuit and producing a frame synchronous signal, wherein said reception part receives input frame signals from a plurality of input side transmission lines and applies said input frame signals to said cross connect equipment while said transmission part is provided with cross connected input frame signals from the cross connect equipment, reforms said cross connected frame signals into signals having a specified frame format and retransmits said signals as output frame signals to respective output side transmission lines in synchronism with said frame synchronous signal produced by said frame counter, the pointer processing circuit being installed in said reception part at said cross connect equipment so that pointer processing of said frame signals is carried out for every input side transmission line and each input frame signal has a pointer value before cross connection thereof, said pointer processing circuit comprising means to detect a phase difference between said input frame signal of each of said input side transmission lines and said frame synchronous signal from said frame counter and adjust the pointer value of said input frame signal for each of said input side transmission lines based on the thus detected phase difference signal so that the phase difference is cancelled.
1 Assignment
0 Petitions
Accused Products
Abstract
A pointer processing circuit which is incorporated in a SONET transmission apparatus having a cross connect equipment, is installed in the reception part of the cross connect equipment. The pointer processing circuit detects a phase difference between a multiplexed input frame signal for each input side transmission line, and receives a frame synchronous signal by which output frame signals are commonly synchronized. The frame synchronous signal is produced by a frame counter connected to the pointer processing circuit. The pointer processing circuit has a unit for adjusting a pointer value of the multiplexed input frame signal, based on the thus detected phase difference, before the cross connection of the input frame signals.
32 Citations
8 Claims
- 1. A pointer processing circuit in combination with a cross connect equipment in a SONET transmission system which has said cross connect equipment between a reception part and a transmission part, and a frame counter connected to said pointer processing circuit and producing a frame synchronous signal, wherein said reception part receives input frame signals from a plurality of input side transmission lines and applies said input frame signals to said cross connect equipment while said transmission part is provided with cross connected input frame signals from the cross connect equipment, reforms said cross connected frame signals into signals having a specified frame format and retransmits said signals as output frame signals to respective output side transmission lines in synchronism with said frame synchronous signal produced by said frame counter, the pointer processing circuit being installed in said reception part at said cross connect equipment so that pointer processing of said frame signals is carried out for every input side transmission line and each input frame signal has a pointer value before cross connection thereof, said pointer processing circuit comprising means to detect a phase difference between said input frame signal of each of said input side transmission lines and said frame synchronous signal from said frame counter and adjust the pointer value of said input frame signal for each of said input side transmission lines based on the thus detected phase difference signal so that the phase difference is cancelled.
Specification