Abstract:
The present invention is related to a circuit (1) for detecting activity in a burst-mode receiver. The circuit is arranged for receiving an input signal (2) comprising a preamble. The circuit comprises a differentiator (11) for detecting signal transitions in the input signal (2) whereby the preamble comprises information on operating said differentiator (11). In a preferred embodiment, the information is a time constant. The circuit further comprises an integrator (12) arranged for being fed with an output of the differentiator. The resulting signal is compared to a reference (16). If this reference is crossed, activity is detected. In an embodiment a front-end circuit is presented comprising next to a circuit for detecting activity, a reset circuit arranged for resetting the front-end circuit and a clock phase alignment circuit arranged for recovering the phase.
Abstract:
An optical receiver for receiving a first input data signal and a second input data signal, the optical receiver comprising: a first photo-detector, the first photo-detector operable to receive the first input data signal and operable to output a first electrical signal; a second photo-detector, the second photo-detector operable to receive the second input data signal and operable to output a second electrical signal; a phase-locked-loop, the phase-locked-loop operable to receive a reference clock signal; a clock-recovery circuit, the clock-recovery circuit coupled to the phase-locked-loop, the clock-recovery circuit operable to receive the first electrical signal; a latch-decision circuit, the latch-decision circuit coupled to the clock-recovery circuit; and a latch, the latch coupled to the latch-decision circuit, the latch operable to receive the first electrical signal and the second electrical signal.
Abstract:
A method for generating a variable delay of a signal (28), including: providing a clock (50) indicating a sequence of sample times at regular intervals and receiving a sequence of input samples (41) representing input values of the signal at respective sample times indicated by the clock. The method further includes determining the delay (40, 46) with a temporal resolution substantially finer than the clock interval to be applied to the signal at each of the respective sample times. For each of the sample times, responsive to the respectively-determined delay, one or more of the input samples are processed so as to generate a corresponding output sample (43) representing a delayed output value of the signal at the sample time.
Abstract:
A clock signal distribution system provides a set of synchronized, spatially distributed local clock signals (CLKL). The system includes a source of periodic reference clock signal (CLK), a set of spatially distributed deskewing circuits (12) and first and second transmission lines (18 and 20). The first transmission line routes the reference clock signal from the source (14) to the deskewing circuits in a first order of succession. The second transmission line routes the reference clock signal from the source to the deskewing circuits in a second order of succession that is reverse to the first order of succession. The two transmission lines are of similar length and velocity of signal propagation between adjacent deskewing circuits. Each deskewing circuit produces an output local clock signal having a phase that is midway between phases of the clock signal arriving at the deskewing circuit via the first and second transmission lines. The local ouput signals produced by the deskewing circuits all have the same phase and frequency despite varying distances of the deskewing circuits from the clock source.
Abstract:
In order to realize data transfer between a transmitter and a receiver at high speed with a small amount of hardware and an inexpensive mounting system and to provide a data transferring device which can make lighter the designing work of the system, a reference signal generated by a reference signal generating circuit is transmitted together with data from the data transmitting side, delayed by a phase adjusting circuit, and phased with the clock on the receiving side by a phase detecting/phase controlling circuit. A data signal group is delayed by the same delay of the reference signal, so that the data signals can be directly taken in at the timing of the receiving-side clock. The skew of the clock can be strictly controlled and the long detour of a data transferring line and useless waiting time for signal value determination are reduced.
Abstract:
Transpositional Modulation, TM: The idea behind it can be seen as superimposing two different modulations in the same time/frequency resource. More in details: TM produces first a conventionally modulated (QAM, PSK... ) carrier signal, extracts its carrier, slightly modifies it so that the carrier wave also carries information at the pace of one bit per carrier wave period (more than 1 Gbit/s for LTE), and superimposes both signals for transmission. At the receiver, successive interference cancellation is performed: First conventionally modulated signal is detected, subtracted from received signal, and then TM signal is detected. The TM modulation implies third harmonic processing at the transmitter and receiver.
Abstract:
In one aspect of the teachings herein, a timing circuit detects the assertion of an incoming timing pulse signal at a timing resolution higher than that afforded by the sampling clock signal used to detect the assertion event. To do so, the timing circuit uses delay circuitry to obtain incrementally delayed versions of the incoming timing pulse signal or sampling clock signal. The delay increments are fractions of the sampling clock period and the timing circuit uses the delayed versions to determine a timing difference between actual assertion time of the incoming timing pulse signal and the sampling clock edge at which assertion of the incoming timing pulse signal is detected. In another aspect, a timing circuit uses similar delay techniques to control the timing of an outgoing timing pulse signal at a timing resolution higher than that afforded by the clock circuitry associated with generating the outgoing signal.
Abstract:
Described are phase adjustment circuits for clock and data recovery circuits (CDRs). Systems and apparatuses may include an input to receive a serial data signal, an edge data tap to sample transition edges in the serial data signal for generating a data edge detection signal, a CDR circuit including a phase detector to receive the serial data signal and the data edge detection signal, and to output a phase lead/lag signal indicating the phase difference between the serial data signal and the data edge detection signal, and a phase adjustment circuit to generate phase lead/lag adjustment data. The CDR circuit is to output a recovered clock signal based, at least in part, on the phase lead/lag signal adjusted by the phase lead/lag adjustment data.
Abstract:
An all-optical time slice switching method based on time synchronization is provided. With the method, continuous data streams in an optical network are assembled to time domain periodic optical time slices and are transmitted in an asynchronous transmission mode. Network nodes obtain high precision synchronization time via a network and control optical switches to switch arriving optical time slices to a target port at precise time points periodically, therefore all-optical switching is implemented. When a connection request arrives, an available path, a wavelength and time slots to be occupied are calculated by a source node according to information on available time slots of the optical network, and the time slots are reserved by a connection management module. After the time slots are reserved, the source node send optical time slices carrying services periodically at reserved time slots. A destination node restores the optical time slices to the data streams. Compared with an existing switching technology, the all-optical time slice switching method has remarkable advantages that reliable and flexible all-optical switching at sub-wavelength granularity can be implemented without participation of all-optical buffers and all-optical logic apparatus.
Abstract:
Es sind eine Vorrichtung (5) und ein Messverfahren zur Ermittlung der internen Verzögerungszeit einer CAN-Busanschlusseinheit (11, 21, 31) bereitgestellt, um eine korrekte Funktion einer seriellen Datenübertragung in einem Bussystem (4) mit mindestens zwei Teilnehmerstationen (10, 20, 30) zu prüfen, wobei die Teilnehmerstationen (10, 20, 30) über eine Busanschlusseinheit (10, 20, 30) an den Bus (40) angeschlossen sind und über den Bus (40) Nachrichten (41) austauschen, wobei der Sendezugriff auf den Bus (40) für jede Nachricht (41) durch das Arbitrierungsverfahren gemäß CAN-Norm ISO 11898-1 an eine Teilnehmerstation (10, 20, 30) vergeben wird, welche für diese Nachricht (41) zum Sender wird. Wobei die Vorrichtung (5) eine Einheit aufweist zur Ermittlung der internen Verzögerungszeit (DELTA_T) mit einem Verzögerungszähler (305) zum Ermitteln der Verzögerungszeit (DELTA_T) zwischen einem Sendesignal (CAN_TX) und einem Empfangssignal (CAN_RX), welcher Verzögerungszähler (305) gestoppt wird, wenn sowohl das Empfangssignal (CAN_RX) einen dominanten Pegel hat als auch der Zählerstand des Verzögerungszählers (305) größer/gleich einem vorgegebenen Konfigurationswert (T_MIN) ist, oder zur Ermittlung der internen Verzögerungszeit (DELTA_T) auf der Grundlage der maximalen und minimalen Verzögerungszeit der Busanschlusseinheit (11, 21, 31). Das Stoppen des Verzögerungszählers erst nach einem minimalen Zählerstand erhöht die Messgenauigkeit bei Signalstörungen, z.B. durch Signalreflexionen.