摘要:
The present invention describes a method implemented by a radiofrequency device of a gateway of a remote-reading apparatus which also includes a plurality of meters, the gateway also including a hub communicating with said radiofrequency device as well as with an external telecommunications network, the method including the steps of: receiving from the hub a downstream gateway signal produced in accordance with a network synchronisation signal from a clock of the external telecommunications network; and adapting the radiofrequency transmissions to the meter and/or the radiofrequency receptions from the meter using said received downstream gateway signal, such that the phase and/or frequency of said radiofrequency transmissions and/or receptions are phase-synchronised in accordance with the network synchronisation signal.
摘要:
A transmission device (10) includes: a series/parallel converter (11); an MSK modulator (31) for modulating a signal on a channel basis; a D/A converter (13); a frequency converter (14a) for conversion into different carrier frequencies; a synchronization circuit (32); an amplifier (15); a multiplexer (16) for multiplexing amplification signals; and an antenna (19). A reception device (20) includes: an antenna (21); a demultiplexer (22); a frequency converter (23) for converting signal demultiplexed on a channel basis into a baseband frequency; a low-pass filter (33) for removing a higher-harmonic component of the signal; an A/D converter (24); a digital filter (36) for extracting a main wave component from the digital signal; a sampling point detection circuit (35a) for detecting a sampling point from the main wave component; an MSK demodulator (34a) for reproducing and demodulating a symbol point based on detection information by an interpolation process; and a parallel/series converter (26) for restoring an original signal from the demodulated signal.
摘要:
The specification describes an optical modulator implemented with an MSK format. The modulator creates two separate pulse streams (one pulse stream comprising the odd bits and the other comprising the even bits of the data stream) using a 1-by-2 pulse generator (13, 14, 16). The modulator then uses electrooptic phase modulators (17, 18) to encode the odd and even numbered bits separately, and a 50/50 coupler (21) to remix them.
摘要:
In an MSK transmitter, the digital data signal is split (11) into I and Q channels (121,122). Instead of applying these directly to the quadrature modulator (2), the I channel is applied first to an inverter (3), and the switch (4) selects either the I signal (121) or the inverted I (123) signal. The unaltered I signal is used when the local oscillator in the receiver is synchronous to that in the transmitter. Otherwise the inverted I signal is used.
摘要:
An apparatus comprising: a matched filter (1403) to generate an output pulse (1411) based on a received preamble (1352); a plurality of symbol code correlators (1504), each symbol code correlator outputting a correlation signal (1506) based on a received symbol code (1354); and a center seeking circuit (1412) coupled to the matched filter, the center seeking circuit outputting a timing reference signal (1413,1414) indicative of a center of an output pulse.
摘要:
A method comprising receiving/transmitting a spread spectrum preamble (1351,1385,1390) from a transceiver (1337); and receiving/transmitting a spread spectrum encoded data message (1354,1387,1392) following the spread spectrum preamble from the transceiver, the spread spectrum encoded data message lagging the spread spectrum preamble by a preamble sounding gap (1353,1386,1391) during which the transceiver does not transmit/receive.
摘要:
Methods and apparatus for the transmission and reception of coded-phase modulation spread-spectrum communication signals are presented. The various embodiments include such features as coherent or non-coherent reception; differential encoding and decoding; serial or parallel correlation (815, 820); demodulation based on the phase of the received signal; and choice of modulating codes from tables based on the input data or on other information to be transmitted.