A pulse modulation method divides code comprising 4N-bit data into 2-bit units of data. For each pulse signal having a fixed pulse width tw, a code modulated signal is generated by pausing between pulse pause intervals Tr. An adjusted time width of between ½ and 1 times the fixed pulse width tw is taken to be Δt. One of time widths 0, Δt, 2Δt, and 3Δt is added to a fixed pause period tm of time intervals according to a corresponding value of the 2-bit data. If the sum total time TD of the code modulated signal is an interval of at least [(2tw+2tm+3Δt)N+Δt], each pulse pause interval Tr is substituted by a pulse pause interval Tr corresponding to the inverted 2-bit data. An inversion flag signal expresses that inversion information is added to the code modulated signal.

Pulse modulation method

A communication device including an RF transmitter mounted in conjunction with an IR transmitter allowing data to be transmitted by RF as well as by IR. Such a device may be a portable badge worn by moving personnel to transmit IR and RF signals to one of a plurality of second devices each being a fixed reader having an IR and RF receiver, and typically being mounted in a respective enclosed space, such as a room. In use, IR transmissions from the portable device are detected by the IR receiver of the reader in the same room and thus provide an immediate identification of the room (or enclosed space) wherein the portable device is located. On the other hand, if the IR transmitter in the portable device is concealed or for any other reason is not within line-of-sight of the reader in its immediate proximity, then the RF signal transmitted by the RF transmitter in the portable device is detected by the RF receiver in the reader, thereby allowing tracking of the portable device in either eventuality.

Dual rf/ir communication device and method of use thereof

A method and apparatus for transmitting information over a wireless connection are provided. A correlation is established between a set of symbols and a set of pulse position/signal characteristic combinations. Thus, each symbol has a corresponding pulse position and a corresponding signal characteristic. The signal characteristic may be, for example, a particular frequency, amplitude or phase. To communicate a symbol, a device generates a signal in which a tone burst is sent during the pulse position that corresponds to the symbol. In addition, at least some portion of the signal reflects the signal characteristic that corresponds to the symbol. A receiving device determines the pulse position in which the tone burst was sent and determines the signal characteristic reflected in the signal. The receiving device then determines the symbol based on the pulse position and the signal characteristic. Synchronization is improved by generating synchronization tone bursts before each pulse position modulation frame. Inter-symbol interference is minimized by placing guard bands on each side of the synchronization pulse and/or between pulse windows in each pulse position modulation frame.

Method and apparatus for multi-mode infrared data transmission

A high-speed out-of-band signalling technique for transferring information such as station status information between stations in a communication network, typically a local-area network, involves sequentially generating a plurality of n-bit sequence segments, where n is at least 3. Each bit is either a first binary value or a second binary value. Each sequence segment is coded with one of a plurality of different n-bit code groups divided into a first code group and a set of second code groups. The n bits in the first code group are all the first binary value, e.g., all '1s'. None of the second code groups contain a pair of non-contiguous bits of the second binary value, e.g., none of the second code groups contains two 'Os' separated by at least one other bit. The sequence segments are outputted in the order that they were generated to produce a special bit sequence which carries the desired information. The station status information typically includes configuration capability, flow control parameters, and integrity control parameters.

Signalling method and structure suitable for out-of-band information transfer in communication network

A method for modulating a radio signal has the steps of: predetermining a first time interval so as to define a data word; generating a synchronization pulse, the synchronization pulse initiating a single data word having a length of the predetermined first time interval; and generating a single data pulse within the data word after a second time interval with respect to the synchronization pulse, the length of the second time interval defining at least one character. Defining at least one character by a single data pulse after a second time interval with respect to the synchronization pulse enhances an energy efficiency of the transmitted radio signal while mitigating a duty cycle thereof.

Pulse position modulation communications protocol

A data transmission system and method in which digitalized information is transmitted via a data transmission link in complete binary words from a transmitter to a receiver. For data transmission, a complete binary word with a defined total bit number is subdivided into one or more partial binary words, with the respective bit numbers of the partial binary words being variable. The individual partial binary words are allocated all binary bit sequences that can be formed with the total number bits of the respective partial binary words, the various bit sequences being coded at respectively different positions within a partial binary word In each partial binary word exactly one binary bit sequence is transmitted from the transmitter to the receiver.

Helmut Moser

Papers

Data transmission system