Disclosed is a method of distributing a number of reference clocks across a packet network. The packet network has a master node and one or more slave nodes, the master node and each slave node having basis clocks. A sender sends time-stamped synchronization packets to said one or more slave nodes, and a receiver at the slave nodes receives the time-stamped synchronization packets and synchronizes the basis clocks in the slave nodes with the basis clock in the master node. Multiple reference clocks are encoded with respect to the basis clock in the master node to generate numerical information describing the reference clock(s) in relation to the basis clock in the master node. The basis clock in each of the slave node is synchronized to the basis clock in the master node using time-stamped synchronization packets. The one or more reference clocks are recovered at the slave nodes using said numerical information describing the reference clock(s) in relation to the basis clock in the master node.

Method providing distribution means for reference clocks across packetized networks

A mobile wireless communications system including a plurality of individual transponding nodes of various types, all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The number of transponders and codes used to transmit each user signal can be readily adapted to user requirements.

Multi-platform wireless communication system for a variety of different user types

Disclosed herein are systems and techniques for slave-to-slave communication in a multi-node, daisy-chained network. Slave nodes may provide or receive upstream or downstream data directly to/from other slave nodes, without the need for data slots first to route through the master node.

Synchronous slave-to-slave communications

A circuit, such as, but not limited to, a digital phase-locked loop (PLL) or a transport timing loop, uses a fractional-N modulator and a fractional-N clock synthesizer to generate a clock signal, such as a transmit clock signal, from a reference clock signal. One embodiment uses a recovered clock signal derived from serial received data as a positive input to a feedback loop, and uses the transmit clock signal as a negative input to the feedback loop. After digital phase detection and digital filtering, a filtered error signal s is generated and used to control a modified fraction for control of the fractional-N synthesizer. Disclosed techniques advantageously exhibit jitter attenuation and have relatively little jitter accumulation, which are useful characteristics in telecommunication and data communication network clocking applications. Embodiments can be applied to loop timing, clock regeneration, and transport timing applications, and can be used when clock holdover is desirable.

Jitter attenuation with a fractional-N clock synthesizer

Disclosed herein are systems and techniques for general purpose input/output (GPIO)-to-GPIO communication in a multi-node, daisy-chained network. In some embodiments, a transceiver may support GPIO between multiple nodes, without host intervention after initial programming. In some such embodiments, the host may be required only for initial setup of the virtual ports. In some embodiments, GPIO pins can be inputs (which may change virtual ports) or outputs (which may reflect virtual ports). In some embodiments, multiple virtual ports may be mapped to one GPIO output pin (with the values OR'ed together, for example). In some embodiments, multiple GPIO input pins may be mapped to one virtual port. For example, multiple GPIO input pin values may be OR'ed together, even if they come from multiple nodes.

GPIO-to-GPIO communication on a multi-node daisy-chained network

A communication system, source and destination ports of the communication system, and methodology is provided for transporting data in one of possibly three different ways. Data is transported across the network at a frame sample rate that can be the same as or different from the sample rate or master clock within the source port or the destination port. If the sample rate of the source port is known, the sample rate of the destination port can be created using a PLL within the destination port and simply employing a phase comparator in the source port. The phase comparator forwards the phase or frequency difference of the network transfer rate and the source sample rate to the destination port, which then generates a local clock equivalent to the source which then compiles audio data being played at the same rate in which it was sampled at the source. Where economically feasible, sample rate conversion can be used at the source. However, sample rate conversion at the destination is preferred if the source sample rate is forwarded across the network relative to the frame transfer rate of the synchronous network. The sample rate converter simply produces a play rate from the transmitted information at the destination. Again, however, sample rate conversion compares relative phase difference changes similar to the phase difference compared in the digital PLL mode. As a further alternative, sample rates within the source and destination ports can be derived from the network frame rate using fractional dividers in the source and destination ports.

Communication system and method for generating slave clocks and sample clocks at the source and destination ports of a synchronous network using the network frame rate

Communication system for sending and receiving data onto and from a network at a network frame rate using a phase locked loop, sample rate conversion, or synchronizing clocks generated from the network frame rate

Matthias Winkelmann

Papers

Communication system and method for generating slave clocks and sample clocks at the source and destination ports of a synchronous network using the network frame rate

Communication system for sending and receiving data onto and from a network at a network frame rate using a phase locked loop, sample rate conversion, or synchronizing clocks generated from the network frame rate