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An inductor-less wideband (6-18 GHz) 3-bit attenuator with low phase variations is presented based on octagonal SiGe p-type intrinsic n-type (pin) diodes. To achieve low insertion loss and high linearity, a DC bias scheme has been designed to minimise the leakage from the parasitic diodes between the P-sub and N-well of the pin diodes. The attenuator is fabricated in a standard 0.18 µm SiGe BiCMOS process without using post-processed transmission lines. It has a maximum attenuation range of 7 dB. The minimum measured insertion loss is 7.9, 9.4, 10.6 dB at 6, 12, 18 GHz, respectively. Phase variation is lower than ±2.5° and the chip size, including pads, is 0.85×0.412 mm2. [ABSTRACT FROM AUTHOR]

A simplified orthogonal frequency division multiplexing (OFDM) system with low peak-to-average power ratio (PAPR) and frequency diversity is proposed. The considered OFDM system exploits a frequency diversity by using a simple symbol repetition as is the case in previous work (i.e. Ko et aL, MILCOM2002). From the presented results, it can be seen that a modified OFDM signal can be easily implemented with low PAPR, still maintaining the same diversity gain at the receiver as in Ko et al. However, a small increase of decoding delay may be expected. [ABSTRACT FROM AUTHOR]

Current-reuse and gate-modulation techniques have been presented for ultra-low power and low phase noise quadrature voltage-controlled oscillator (QVCO) design. The proposed topology overcomes the trade-off between low phase noise and low power consumption. Results demonstrate a phase noise of -123.7 dBc/Hz at 1 MHz offset while consuming only 680 uW (including output buffers) with a 1.1 V supply. [ABSTRACT FROM AUTHOR]

A fast scattered pilot synchronisation algorithm is presented which detects the pilot pattern of the currently received OFDM symbol for the DVB-H. The proposed synchronisation scheme is based on the correlation between the neighbouring pilot subcarriers in one received OFDM symbol. Therefore, it can reduce the burst synchronisation time with robustness compared with the conventional method used for DVB-H. [ABSTRACT FROM AUTHOR]

This article discusses PAPR analysis for multi-band OFDM signals. A multi-band orthogonal frequency division multiplexing (MB-OFDM) is being considered as a possible candidate for the IEEE 802.15 high rate alternative PHY. A MB-OFDM system exploits a frequency diversity introduced by both a multi-band hopping over two OFDM symbols and a conjugate symmetric input to inverse fast Fourier transform. In this article, researchers analyse the PAPR statistics for MB-OFDM signal and provide the selective mapping and partial transmit sequence-based MB-OFDM signals.