摘要:
An adapter which attaches Data Terminal Equipment (DTE) to a LAN includes a latch whose state is changed by conditions, such as a free token or a frame, on the LAN. The output of the latch is used to calculate the bandwidth utilization of the LAN.
摘要:
Dual detection paths containing speed recognition devices automatically determine the rate at which data is being transmitted on a multi-rate digital data communications network such as a token ring network. The multiple detection paths operate simultaneously with each detection path provided with a Phase Lock Loop (PLL) and a pattern recognition device. The PLL and its associated pattern recognition device are made to operate at one of the known ring speeds. The ring speed is determined by the detection path which is able to recognize a predetermined data pattern from the network.
摘要:
A multi-frame stripping method for use in a token ring network utilizing early token release with multiple frames transmitted by multiple stations circulating around the ring. The method recovers the ring with minimum loss of data after detection of an error condition resulting in frame corruption. The transmitting station is responsible for removing its own frames from the ring. With one or more of its frames corrupted, a station terminates frame removal after the transmitter has finished transmitting when a frame is received from another station without code violation errors in the frame header if the frame counter has returned to its initial value. The station terminates stripping when only a single frame is transmitted and then becomes corrupted if an isolated ending delimiter is detected at the station. The station also terminates stripping in the multi-frame case when the ending delimiter of the last frame transmitted by the source station is received without code violation error in the I-bit, if each preceding ending delimiter is correctly detected regardless of data corruption occurring in any frame header. The method is applicable to the IEEE 802.5 and ANSI X3T9.5 (FDDI) standards.
摘要:
A frame stripping algorithm for use in a ring communication network utilizing early token release wherein multiple frames can exist on the ring at one time. The algorithm introduces two new strip terminating conditions which supplement two of the three conditions applicable to a normal token release scheme. The first of these conditions occurs when the source address in a received message is not the same as the receiving station's address and no code violation errors have been detected. The second condition occurs when the receiving station detects an isolated ending delimiter without a preceding starting delimiter.
摘要:
An adapter which attaches Data Terminal Equipment (DTE) to a LAN includes a latch whose state is changed by conditions, such as a free token or a frame, on the LAN. The Output of the latch is used to calculate the bandwidth utilization of the LAN.
摘要:
A system and method is provided for estimating the bit error rate of a data signal which has been reconstructed from a received data signal. The system comprises (i) logic for determining timing degradation and amplitude degradation of the received data signal; (ii) an actual bit error rate calculator for calculating the actual bit error rate of the reconstructed data signal; (iii) an instantaneous bit error rate calculator for estimating a bit error rate of the reconstructed signal using the timing degradation and the amplitude degradation; (iv) a first integrator for integrating the estimated bit error rate; (v) a comparator for comparing the integrated estimated bit error rate with the actual bit error rate and outputting an error signal which modifies the estimated bit error rate; and (vi) a second integrator for integrating the estimated bit error rate. The time constant associated with the second integrator is shorter than the time constant associated with the first integrator.
摘要:
This invention is a method and apparatus for detecting the impending impact of a moving vehicle with another object whether the moving vehicle is approaching, or being approached by the vehicle containing the apparatus for such detection. It is further characterized by the placement of impact air bags between the body and the forward or rearward bumper of the vehicle and by an apparatus and method for partially filling such air bags so as to prepare such vehicle for impact with another object or vehicle. The actual impact between the vehicle and said other object further rapidly fills the air bag to its fullest capacity in order to allow the minimal damage to the two vehicles and the passengers therewithin.
摘要:
An air bag system to protect occupants of automobiles against injury in case of collision. An air bag is housed, when empty, in a tapered open container in the passenger compartment of the car. It is inflated by compressed air from an air tank in the vehicle. Inflation is controlled by solenoid valves actuated by switches responsive to excessive brake pedal pressure, harness tension, or force against the front bumper. The speed of inflation may vary. A manual switch controls a deflation pump which deflates the bag and also mechanically draws it back into its container. Normal repeated use of the brake pedal operates air pumping means to keep up the pressure in the air tank.
摘要:
An adaptive regeneration system is provided for reconstructing a signal received in the form of a multi-level composite data and clock signal which has been degraded with respect to amplitude and timing. The system includes a local clock circuit for outputting a plurality of phase-delayed local clock signals, and a clock recovery circuit for receiving the received multi-level signal and the plurality of phase-delayed clock signals and extracting a phase-delayed local clock signal which most accurately represents the phase shift between the received multi-level signal and the local clock signal. A threshold level selection circuit receives the extracted phase-delayed local clock signal and the received multi-level signal and outputs in real time a data amplitude reading and a plurality of multi-level threshold levels corresponding to the amplitude levels of the received multi-level signal. A data regenerator receives the data amplitude reading, the plurality of multi-level threshold levels and the extracted phase-delayed signal and reconstructs and outputs the received multi-level signal essentially in its originally transmitted form.
摘要:
A method and apparatus for enabling the transmitter to decide the number of variable length frames that can be trasmitted within the token holding timer (THT) window. The last frame decision algorithm enables the transmitter to set the intermediate frame bit in the ending delimiter to the right state to indicate the status of each frame in the transmitted frame sequence. A look-ahead technique is used to check the remaining transmit time available in the THT time window, therefor, no ring bandwidth is wasted on partially transmitted aborated frames, effectively optimizing the throughput of the network. Since key variables in the last frame decision algoritm are softwar programmable, the algorithm is independent of ring speed. The algorithm counts transmitted octets instead of measuring transmission time in deciding whether to transmit an additional frame. The algorithm can be applied to either signal frame or multi-frame transmit mode and to either normal or early token release. It is applicable to both the IEEE 802.5 local area network standard for token ring networks and the AnSI X3T9.5 standard for FDDI.