三项与空调有关的国家标准即将出台

2003年12月22至24日，中国冷冻设备标准化技术委员会(以下简称“冷标委”)在广西北海召开会议，审查通过了《空调风机噪声声功率级测试——混响室法》(以下简称《噪声标准》)、《轨道车辆用空调机组》(以下简称《车辆机组标准》)、《空调与制冷用高效热换管》(以下简称《换热管标准》)三项国家标准。冷标委樊高定主任透露，这三项国标预计将于2004年中旬出台。

Research on Aircraft Noise Evaluation System

The evaluation system of aircraft noise and environment noise should be integrated, because aircraft noise belongs to environment noise. At the same time, there should be some difference in the evaluation system of aircraft noise. For solving this contradiction, this article puts forward a new evaluation system of aircraft noise. This new system unifies the evaluation of aircraft noise and other environment noise effectively, and adds a new evaluation index single event noise exposure level. The system not only considers the characteristics of aircraft noise, which is different from other traffic noise, but also adds aircraft noise to other traffic noise, which can reflect sound environment around airport really. This system has practical worthiness and theory significance.

A Fully Integrated 60GHz Four Channel CMOS Receiver with 7GHz Ultra-Wide Bandwidth for IEEE 802.11ad Standard

In this paper, a fully integrated CMOS receiver frontend for high-speed short range wireless applications centering at 60GHz millimeter wave （mmW） band is designed and implemented in 90nm CMOS technology. The 60GHz receiver is designed based on the super-heterodyne architecture consisting of a low noise amplifier （LNA） with inter-stage peaking technique, a single- balanced RF mixer, an IF amplifier, and a double-balanced I/Q down-conversion IF mixer. The proposed 60GHz receiver frontend derives from the sliding-IF structure and is designed with 7GHz ultra-wide bandwidth around 60GHz, supporting four 2.16GHz receiving channels from IEEE 802.1lad standard for next generation high speed Wi- Fi applications. Measured results show that the entire receiver achieves a peak gain of 12dB and an input 1-dB compression point of -14.SdBm, with a noise figure of lower than 7dB, while consumes a total DC current of only 60mA from a 1.2V voltage supply.

STATISTICAL PROBABILITY BASED ALGORITHM FOR EXTRACTING FEATURE POINTS IN 2-DIMENSIONAL IMAGE

An algorithm for automatically extracting feature points is developed after the area of feature points in 2-dimensional (2D) imagebeing located by probability theory, correlated methods and criterion for abnormity. Feature points in 2D image can be extracted only by calculating standard deviation of gray within sampled pixels area in our approach statically. While extracting feature points, the limitation to confirm threshold by tentative method according to some a priori information on processing image can be avoided. It is proved that the proposed algorithm is valid and reliable by extracting feature points on actual natural images with abundant and weak texture, including multi-object with complex background, respectively. It can meet the demand of extracting feature points of 2D image automatically in machine vision system.

Robust Digital Non-Linear Self-Interference Cancellation in Full Duplex Radios with Maximum Correntropy Criterion

Full duplex radio increases the frequency efficiency but its performance is limited by the self-interference （SI）. We first analyze the multiple noises in the full duplex radio system and model such noises as an α - stable distribution. Then we formulate a novel non-Gaussian SI problem. Under the maximum correntropy criterion （MCC）, a robust digital non-linear self-interference cancellation algorithm is proposed for the SI channel estimation. A gradient descent based algorithm is derived to search the optimal solution. Simulation results show that the proposed algorithm can achieve a smaller estimation error and a higher pseudo signal to interference plus noise ratio （PSINR） than the well-known least mean square （LMS） algorithm and least square （LS） algorithm.

Analysis of external noise spectrum of high-speed railway

A schematic to make the spectra of the exterior noise of high speed railway was put forward. The exterior noise spectrum was defined based on the characteristics of the high-speed train exterior noise. Its characteristics considered here include identifying the exterior main sources and their locations, their frequency components including the Doppler effect due to the noise sources moving at high speed, the sound field intensity around the train in high-speed operation, the sound radiation path out of the train, and the pressure level and frequency components of the noise at the measuring points specified by the International Organization for Standardization(ISO). The characteristics of the high-speed train exterior noise of the high speed railways in operation were introduced. The advanced measuring systems and their principles for clearly indentifying the exterior noise sources were discussed in detail. Based on the concerned noise results measured at sites, a prediction model was developed to calculate the sound level and the characteristics of the exterior noise at any point where it is difficult to measure and to help to make the exterior noise spectrums. This model was also verified with the test results. The verification shows that there is a good agreement between the theoretical and experimental results.

Unitary Application of the Quantum Error Correction Codes

For applying the perfect code to transmit quantum information over a noise channel,the standard protocol contains four steps:the encoding,the noise channel,the error-correction operation,and the decoding.In present work,we show that this protocol can be simplified.The error-correction operation is not necessary if the decoding is realized by the so-called complete unitary transformation.We also offer a quantum circuit,which can correct the arbitrary single-qubit errors.