Abstract: Antenna system connectable to a base station, the antenna system comprising a digital radio unit connectable to at least one antenna element, wherein the digital radio unit comprises: at least one micro radio for receiving/sending digital radio signals having a digital down-converter/a digital up-converter and a digital signal converter. The at least one micro radio converts the digital radio signals to analogue RF (radio frequency) signals and vice versa. The at least one micro radio has at least one hub for processing digital radio signals and control signals and for routing said digital radio signals and control signals via at least one serial link and at least one interface. The at least one serial link is provided between the at least one hub and the at least one micro radio.

Abstract: Digital Transceiver (DTRX) usable in a radio communications systems for transmitting and receiving digital base-band signals, wherein the DTRX (300) comprises: at least one digital up-converter (DUC) (310) for transmitting digital base-band signals and at least one digital down-converter for receiving digital base-band signals. In one aspect of the teachings disclosed herein the DUC (310) comprises at least two over-sampling units (314, 315), at least one quadrature modulation unit (340), and at least one time-discrete sigma delta band-pass modulator (318). The digital down-converter comprises at least one quadrature demodulation unit (360), at least two decimator units (356,357), and at least two sub-sampling units (354, 355). The digital base-band signal comprises an in-phase component (I-signal) and a quadrature component (Q-signal).

Abstract: A digital sigma-delta modulator (100) for modulating a digital input signal (x) is described. The digital sigma-delta modulator (100) comprises a quantizer (115) for quantizing an input signal (s) and producing a quantized output signal (y) at a first output (110) and an error output signal (?q) at a second output (165), at least one feedback loop (120, 125) connected to an input adder (140) and the first outputs (110) and the second output (165) of the quantizer (115) and a feedback filter (130, 135) in the at least one feedback loop (120, 125). The input adder (140) produces the sum signal (s) by adding the digital input signal (x) at an input (105) and output signals of the at least one feedback loop filters (130,135).

Abstract: Digital Transceiver (DTRX) usable in a radio communications systems for transmitting and receiving digital base-band signals, wherein the DTRX (300) comprises: at least one digital up-converter (DUC) (310) for transmitting digital base-band signals and at least one digital down-converter for receiving digital base-band signals. In one aspect of the teachings disclosed herein the DUC (310) comprises at least two over-sampling units (314, 315), at least one quadrature modulation unit (340), and at least one time-discrete sigma delta band-pass modulator (318). The digital down-converter comprises at least one quadrature demodulation unit (360), at least two decimator units (356,357), and at least two sub-sampling units (354, 355). The digital base-band signal comprises an in-phase component (I-signal) and a quadrature component (Q-signal).

Abstract: Antenna system connectable to a base station, the antenna system comprising a digital radio unit connectable to at least one antenna element, wherein the digital radio unit comprises: at least one micro radio for receiving/sending digital radio signals having a digital down-converter/a digital up-converter and a digital signal converter. The at least one micro radio converts the digital radio signals to analogue RF (radio frequency) signals and vice versa. The at least one micro radio has at least one hub for processing digital radio signals and control signals and for routing said digital radio signals and control signals via at least one serial link and at least one interface. The at least one serial link is provided between the at least one hub and the at least one micro radio.

Abstract: A digital sigma-delta modulator (100) for modulating a digital input signal (x) is described. The digital sigma-delta modulator (100) comprises a quantizer (115) for quantizing an input signal (s) and producing a quantized output signal (y) at a first output (110) and an error output signal (?q) at a second output (165), at least one feedback loop (120, 125) connected to an input adder (140) and the first outputs (110) and the second output (165) of the quantizer (115) and a feedback filter (130, 135) in the at least one feedback loop (120, 125). The input adder (140) produces the sum signal (s) by adding the digital input signal (x) at an input (105) and output signals of the at least one feedback loop filters (130,135).