Abstract:
The invention relates to a phase detector, especially for a Phase Locked Loop of a desynchronizer of a digital transmission system for the transmission of signals of the synchronous digital hierarchy with a difference former (subtractor) connected to a comparator, to which can be conducted at the input side, via a first accumulator, a first input signal, and via a second accumulator a second input signal with the comparator being connected at the output side via a coder to a control input of the second accumulator.
Abstract:
The invention relates to a transmission system comprising a control circuit which circuit includes a comparator (18, 19, 20; 25 to 29; 46; 50 to 52, 57 to 60) for comparing a first input signal and a second input signal. For reducing the low-frequency phase error, the comparator (18, 19, 20; 25 to 29; 46; 50 to 52, 57 to 60) is provided for changing the state of a first comparing signal derived from the first input signal and/or the state of a second comparing signal derived from the second input signal, or the state of the output signal resulting from a combination of the two comparing signals at instants denoted by an auxiliary signal whose frequency deviates from the frequency of the signal to be changed.
Abstract:
The invention relates to a measuring device for measuring the phase deviation of at least a subordinate transport unit of a synchronous signal transmitted through a synchronous transmission system. The measuring device comprises a transmitter unit for forming the synchronous signal to be transmitted, a first desynchronizer for splitting up the synchronous signal and for detecting at least a given byte of the subordinate transport unit, a second desynchronizer for splitting up the received synchronous signal which has passed through the transmission system and for detecting at least the given byte in the received synchronous signal, and an evaluation unit for calculating the phase deviation from the moments of detection of at least the given byte in the transmitted and the received synchronous signals.
Abstract:
A circuit for adjusting the bit rates of two signals is necessary for plesiochronous multiplexers, for example, to bring the plesiochronous signals, which are to be combined to one digital signal of the next higher hierarchy, to the same bit rate. For this purpose, the circuit arrangement comprises an elastic store (4) as well as a justification decision circuit (15, 16). In order that a circuit having such features can be used for bit rates of the order of 140 Mbit/s and yet can be arranged largely in CMOS technology, the bit clocks of the first and second signals are reduced at the ratio of 1:n. Furthermore, a serial-to-parallel converter (2) converts bit groups of n serial bits of a first signal into bit groups of n parallel bits, which are written in groups into the elastic store (4) and are also read out in groups. The parallel bit groups read out are applied to a controllable selection matrix (5) having n outputs, which transmits n selected bits of more than one bit group to n outputs. The justification decision circuit (15, 16) controls the reading operation of the elastic store (4) and also the selection matrix (5).
Abstract:
A single signal is formed from two plesiochronous signals. The first signal's data are written in parallel in groups of n bits each. Writing and reading are controlled by respective counters, whose counts are also provided to a subtractor. A control loop for bit rate justification is formed by the subtractor, a controller and the read counter. A track counter counts the stuffed bits modulo n, and stops the read counter for one clock period after each n stuffed bits. The mean value of the subtractor output and the count of the track counter are set off against each other, and their result is used for justification formation and a preparation signal for incrementing the track counter.
Abstract:
A circuit arrangement for adapting the bit rates of two signals includes an elastic store into which the data of the first signal are written in parallel in groups of n bits and from which the data bits of the second signal are read out in parallel. A selection matrix for inserting justification bits in the second signal is connected to the output of the elastic store. Writing into the store is controlled by a write counter and read-out therefrom into the selection matrix is controlled by a read counter. A subtractor forms the difference between the counts. A justification decision circuit, which can be realized all or part in CMOS technology and is capable of bit rates of the order of 140 Mbits per second, is connected to the subtractor and the read counter so as to form a control loop for the elastic store. The justification decision circuit includes a controller which produces an output signal corresponding to a running integrated summation of the differences produced by the subtractor, and a pulse distribution circuit. The output signal of the controller controls the pulse distribution circuit to supply pulses which cause the selection matrix to insert justification bits, and cause the read counter to compensate for a difference in the bit rates of the first and second signals.