Efficient determination of cysteine sulphoxides in Allium plants applying new biosensor and HPLC-MS² methods

Cysteine sulphoxide (CSO) contents of 16 different accessions of garlic (Allium sativum L.) and 15 varieties of onion (Allium cepa L.) were measured using two different rapid analytical methods: a biosensoric approach and a newly developed HPLC-MS2 technique. Both methods allow quantification of naturally occurring cysteine sulphoxides present in Allium plants without time-consuming sample pretreatment such as derivatisation of amino acid derivatives prior to HPLC-separation. It has been found that the amount of alliin, which is the predominant CSO occurring in garlic, varies between 0.2 and 2.2 g/100 g dry matter. Contrary to that, isoalliin representing the main CSO in onion has been detected in significantly lower amounts (0.3 to 1.25 g/100 g dry matter)

Analysis and comparison of indoor wideband radio channels at 5 and 60 GHz

In this paper we present measurement results for indoor wideband radio channels at 5 and 60 GHz. To ensure full comparability, the measurements were carried out under the same conditions by using mostly the same equipment. We analyze path loss, time dispersion, frequency selectivity and the impact of an obstructed line-of-sight at both frequencies. The results are compared and characteristic differences are pointed out

Method for Determining Beamforming Parameters in a Wireless Communication System and to a Wireless Communication System

A method for determining a beamforming vector or a beamforming channel matrix in a communication system including a transmitting station and a receiving station, and a communication system are described. The transmitting and receiving stations include respective antenna groups and respective codebooks include a plurality of predefined beamforming vectors for the antenna group

Semi-blind iterative joint estimation of frequency selective I/Q-imbalance and modulator offset error in direct-conversion transmitters

The compensation of frequency selective I/Q-imbalance and modulator (MOD) offset error can improve the performance of direct-conversion transmitters significantly. For effective compensation of these two effects, the parameter estimation is crucial. In many applications, ``semi-blind'' estimation is desired i.e. not dedicated pilot signals but the communication signals are used for estimation. Conventionally, Least-Square Estimation (LSE) is applied. However, if the communication signal has spectral gaps (e.g. due to oversampling), the LSE will suffer from ill-conditioned matrix problem, which results in severe estimation error. To overcome this problem, we propose an Iterative Frequency Domain Estimation (IFDE) technique, which operates adaptively according to the spectral characteristic of the communication signal and can provide good calibration performance. The effectiveness of the IFDE and its advantage over conventional LSE are verified by numerical simulations

Preamble Based Joint CFO, Frequency-Selective I/Q-Imbalance and Channel Estimation and Compensation in MIMO OFDM Systems

A very promising technical approach for future wireless communication systems is to combine MIMO OFDM and Direct (up/down) Conversion Architecture (DCA). However, while OFDM is sensitive to Carrier Frequency Offset (CFO), DCA is sensitive to I/Q-imbalance. Such RF impairments can seriously degrade the system performance. For the compensation of these impairments, a preamble-based scheme is proposed in this paper for the joint estimation of CFO, transmitter (Tx) and receiver (Rx) frequency-selective I/Q-imbalance and the MIMO channel. This preamble is constructed both in time- and frequency domain and requires much less overhead than the existing designs. Moreover, Closed-Form Estimators (CLFE) are allowed, enabling efficient implementation. The advantages and effectiveness of the proposed scheme have been verified by numerical simulations