Codex Corporation

About: Codex Corporation is a based out in . It is known for research contribution in the topics: Signal & Network packet. The organization has 189 authors who have published 241 publications receiving 32205 citations.

Channel reuse multiple access protocol for bidirectional bus networks

Abstract: A novel contention-free multiple-access protocol for bidirectional-passive bus packet networks is proposed. One version has a simple fixed-assignment transmission scheduling similar to that of the time-division multiple-access protocol, except that left-going and right-going packets may be transmitted only in alternate rounds. Another version employs a simple reservation scheme to provide demand-assignment transmission scheduling. In either instance the protocol may offer a maximum throughput exceeding one packet per packet transmission time under appropriate conditions, where throughput is defined as the number of distinct packets transmitted successfully per packet transmission time. This is possible through channel reuse as explained. >

Frequency range detector

Abstract: A phase lock loop operates independent of temperature and process variation by digitally loading a VCO (22) until reaching the desired operating frequency. The VCO reaches a high output frequency even under worst case processing by controlling multiple current mirrors (162-166, 174-180, 182-188) to increase inverter switching current without slowing the response of the VCO to changes in loop node voltage. An Initialize-to-VDD circuit (32) sets the loop node voltage to VDD so that the load control circuit need only increase loading to slow down the VCO to the desired operating frequency. A frequency range detector (34) monitors the output frequency of the VCO and passes control signals to a load control circuit to (36) activate digital loads (38) and slow down the VCO to the desired operating frequency.

Data communication network

Abstract: A data communication network (10) over which data handling devices (14) can transmit and receive packets among themselves has a bus (22), a number of subnetworks (12) leach having interfaces for connecting a number of devices to each subnetwork), a concentrator (20) for connecting each interface to the bus, each concentrator having a transceiver (110) for transmitting, to the bus and to devices connected to each subnetwork, packets originating from devices within a subnetwork (transmitted packets), and for receiving from the bus packets originating from other subnetworks (received packets), collision avoidance circuitry for monitoring transmission attempts by devices connected to the subnetwork, for detecting competing transmission attempts that would create a collision on the subnetwork, and, upon such detection, permitting a selected attempt to enter the subnetwork, while preventing other attempts from entering it, collision detection circuitry for monitoring the bus and preventing all attempted transmissions from entering the bus whenever a packet from another subnetwork is present on the bus, circuitry for generating a collision signal upon detecting competing transmission attempts, a network interface unit (NIU) (16) associated with each device to cause withdrawal of an attempted transmission by that device upon receipt of a collision signal, a transmit channel over which transmitted packets are transmitted to the bus, a receive channel over which received packets are transmitted to devices connected to each subnetwork, a station interface unit (SIU) (18) intermediate the NIU and concentrator, a first transmit connector over which transmitted packets pass from the NIU to the SIU, a receive connector over which received packets pass from the SIU to the NIU, a collision signal connector over which collision signals pass from the SIU to the NIU, a second transmit connector over which transmitted packets pass from the SIU to the transmit channel, a combined receive and collision signal connector over which collision signals pass from the concentrator to the SIU, and over which received packets pass from the receive channel to the SIU, and demultiplexing circuitry in the SIU for routing collision signals to the collision signal connector and received packets to the receive connector.

Communication apparatus operative to switch dynamically between different communication configurations

Abstract: Communication apparatus is operative to switch communication dynamically between itself and a selected one of a predetermined plurality of mating communication devices of different configurations. A memory (10) is provided for storing a plurality of different sets of configurables with each set of the plurality corresponding to a communication configuration associated with a corresponding mating communication device of the predetermined plurality, each set of configurables being indexed in the storing means by a unique memory address. A controller (12) is also provided and is responsive to a command signal to select an index memory address for use by the communication apparatus to functionally configure itself in accordance with the set of configurables of the memory storage corresponding to the index memory address selected by the command signal.