摘要:
A data transmission system for the non-contact transmission of data between a station (1) and a portable data carrier (2). The station (1) includes a station transmitter (3) operating at a predetermined frequency for generating a first signal and a demodulator (35) for detecting a second signal superimposed on the first signal. An antenna (5) is coupled via a length of cable (4) to the station transmitter (3) via a matching circuit (6) so as to be operative at said frequency regardless of the length of the cable (4). The portable data carrier (2) includes supply means (13) for coupling to a source of electric power and a data carrier tuned antenna circuit (10, 55) inductively coupled with the station transmitter (3) so as to receive power from the station (1). A data carrier data modulator (14) is provided for modulating the first signal with the second signal in response to data stored within the data carrier (2) and, by means of said inductive coupling, enabling the data to be transmitted from the data carrier (2) to the station (1).
摘要:
A self-healing data network and network node controller. Data transmission of data cells to form messages permitting self-clocking operation of each node and elastic buffering implemented to allow receipt of messages without regard to the phase of messages allows asynchronous operation of each node relative to other nodes. Fault detection and network self-healing are performed by each node independently of other nodes.
摘要:
A method is provided for encoding and decoding data to be transmitted over a communication network via transformer coupling. The data is pulse width modulated, and split into separate first and second data streams containing alternate pulses. The first data stream is inverted, and recombined with the second data stream to produce a pulse width modulated bi-polar data signal having an alternating pulse sequence. The data is decoded at the receiver by inverting the pulses of one polarity, and combining them with the pulses of the other polarity to form a pulse width modulated data stream.
摘要:
A method is provided for encoding and decoding data to be transmitted over a communication network via transformer coupling. The data is pulse width modulated, and split into separate first and second data streams containing alternate pulses. The first data stream is inverted, and recombined with the second data stream to produce a pulse width modulated bi-polar data signal having an alternating pulse sequence. The data is decoded at the receiver by inverting the pulses of one polarity, and combining them with the pulses of the other polarity to form a pulse width modulated data stream.
摘要:
A data system for transmitting multi-state data streams between a data transmitting station (1, 10) and a data receiving station (2), coupled together by a data transmission line (3). Associated with the data transmitting station (1, 10) is an encoder (10) for encoding the data stream prior to transmission and associated with the data receiving station (2) is a decoder (23, 24) for decoding the received signals. The encoder (10) comprises signal generating means (15, 16, 17) which selectively generates a first waveform (Fig. 2(b)(i)) corresponding to the integral of a positive pulse having a negative d.c. offset and a second waveform (Fig. 2(b)(ii)) corresponding to the integral of a negative pulse having a positive d.c. offset. The time average of each waveform and its associated d.c. offsets is substantially zero. The encoder (10) further comprises means (18) for reading the multi-state data stream and for outputting a composite waveform onto the data transmission line (3) consisting of a respective combination of the first and second waveforms for each state read from the multi-state data stream. The decoder (23, 24) comprises a differentiating circuit.
摘要:
In a pulse width modulation system, for use in a differential bus within an automobile, the symbol period is divided into three intervals (T1, T2, T3) of unequal duration. In particular T2 is longer than T1, and T3 is longer than T2.
摘要:
According to this invention, there are provided a multilevel weighted transmission method which allows error correction encoders to be reduced to one without error propagation and an apparatus using this method. The multilevel weighted transmission method is such that a plurality of hierarchic information source data strings are subjected to different multilevel weighted coding and modulation by a trellis-coded modulation scheme and the resulting strings are transmitted, and on the reception side, the received signal is subjected to the multilevel weighted demodulation and decoding according to the transmission side to obtain the original hierarchic information source data strings. When the specific first subsets are allocated to the hierarchic levels of the transmission channel in the multilevel weighted transmission and time-division multiplexed at a predetermined ratio, the order of time-division multiplexing the hierarchic levels of the transmission channel is ascending order of the quality of transmission error characteristic.