A generalized frequency division multiplexing method with multiple-input multiple-output and flexible index modulation, which enables to have the energy efficiency provided by space and frequency index modulation systems with generalized frequency division multiplexing (GFDM) without complicating the transmitter and receiver structure and provide for the efficient use of frequency resources, increase in spectral efficiency, minimum complexity and increase in energy efficiency.

A generalized frequency division multiplexing method with multiple-input multiple-output and flexible index modulation, which enables to have the energy efficiency provided by space and frequency index modulation systems with generalized frequency division multiplexing (GFDM) without complicating the transmitter and receiver structure and provide for the efficient use of frequency resources, increase in spectral efficiency, minimum complexity and increase in energy efficiency.

A system 1 for controlling a plurality of irrigation valves 2.sub.1, 2.sub.2 . . . 2.sub.n is shown. The system receives 110 or 240 volts, mains voltage, electricity from the mains. This is applied to a 28 volt square wave generator 3, whose output is modulated in a modulator 4 under control of a control circuit 5. The modulated output is applied to a live line 6, receiving modulated positive and negative pulses of 28 volts with respect to a neutral line 7. At each valve 2.sub.1, 2.sub.2 . . . 2.sub.n, a respective decoder 8.sub.1, 8.sub.2 . . . 8.sub.n is provided. Live and neutral lines 10,11 pass from the decoders to the valves. Each decoder 8.sub.n has an input connector 21 for the live and neutral pair 6,7 powering it and an output connector 22 for the further live and neutral pair 10,11 to the respective valve 2.sub.n.

A distributed antenna system for transceiving radio signals in several frequency ranges is described. The system comprises a control unit with at least one first port for forwarding first radio signals in a first frequency range and one second port for forwarding second radio signals in a second frequency range. A plurality of remote units is connected to the control unit via a distributor network. The remote units have first antenna elements for transceiving the radio signals in the first frequency range and second antenna elements for transceiving the radio signals in the second frequency range. The control unit comprises a modulator for converting the second radio signals to a further frequency range and the remote units have a demodulator for converting the second radio signals from the further frequency range to a different frequency range.

A system 1 for controlling a plurality of irrigation valves 2.sub.1, 2.sub.2 . . . 2.sub.n is shown. The system receives 110 or 240 volts, mains voltage, electricity from the mains. This is applied to a 28 volt square wave generator 3, whose output is modulated in a modulator 4 under control of a control circuit 5. The modulated output is applied to a live line 6, receiving modulated positive and negative pulses of 28 volts with respect to a neutral line 7.

At each valve 2.sub.1, 2.sub.2 . . . 2.sub.n, a respective decoder 8.sub.1, 8.sub.2 . . . 8.sub.n is provided. Live and neutral lines 10,11 pass from the decoders to the valves. Each decoder 8.sub.n has an input connector 21 for the live and neutral pair 6,7 powering it and an output connector 22 for the further live and neutral pair 10,11 to the respective valve 2.sub.n.

In certain aspects, a serial-to-parallel converter includes multiple cascaded stages configured to convert a serial data stream into multiple parallel data signals, wherein each of the stages includes one or more demultiplexers. The serial-to-parallel converter also includes demultiplexer control circuits, wherein each of the demultiplexer control circuits is coupled to the one or more demultiplexers of a respective one of the stages, and a pattern detector coupled to the demultiplexer control circuits.