Zweiweg Kommunikationsgerät mit grosser Reichweite und niedriger Leistung

摘要

The present invention provides a long range, low power communications device (100). The device includes an antenna (114) for transmitting and receiving signals, an analog section (200) coupled to the antenna (114), and a digital section (300) coupled to the analog section (200). More specifically, the analog section (200) includes an intermediate frequency downconverter (204), a digital Inphase output (278), and a digital Quadrature phase output (288). The digital section (300) includes an I/Q derotater (306) producing an I output and a Q output, a wakeup detector (312) including a magnitude output (349), and a threshold comparison circuit (354, 356) coupled to the magnitude output (349). The threshold comparison circuit (354, 356) stores a threshold value indicative of a wakeup signal reception condition, as reflected in the magnitude output (349). The wakeup detector (312) may also, for example, use an accumulator (366) and a moving average circuit (368) between the magnitude output (349) and the threshold comparison circuit (354, 356). In one implementation of the communication device (100), the digital section (300) includes an inner/outer product circuit (358) coupled to the I output and the Q output, and I and Q accumulators (360, 362) for the inner and outer products. Correlators (404, 410) for the inner and outer products may also be included (particularly if modulated wakeup signals are expected). The analog section (200) preferably uses 1-bit analog to digital converters (276, 286) coupled to the intermediate frequency downconverter (204) to produce the digital Inphase output (278) and the digital Quadrature phase output (288).