MODELING OF RADIO TRANSMITTER AMPLIFIERS IN MATLAB CAD

A review of modeling tools for radio transmitter amplifiers in Matlab CAD, as well as their capabilities and limitations, is given.

Radio Transmitter Identification Under Small Sample Conditions

Radio transmitter identification is an emerging technology that uses RFfingerprints to identify different radiation sources, and can find important applications in the field of wireless security.The choice of classifier is one of the key factors affecting recognition performance. Aiming at the shortcomings of a single classifier model, the author proposes a radio transmitter identification method based on improved SVM-KNN. First, the square integral bispectrum(SIB) algorithm is used to extract the signal fingerprint features from the steady-state signal of the mobile phone. Then, instead of the traditional Euclidean distance calculation method, the manifold geodesic distance calculation method is used to calculate the distance between the test sample and each support vector.Experimental studies using the same model of mobile phone show that the improved SVM-KNN algorithm is less affected by the choice of kernel function parameters, and has higher recognition accuracy without increasing the computational complexity. We also proved the robustness of our method in a wide range of signal-to-noise ratio.

Kjente helter og skjulte nettverk: SOE-organisasjonen Cheese og senderen på Helle ved Flekkefjord

This is the story of Cheese, the intelligence and sabotage organisation that, after British initiative, was built around the radio transmitter at Helle in Flekkefjord in January 1941. Cheese was one of the first operations to come to Norway for the purpose of weakening Germany’s military and economic capacity in the occupied country. The transmitter at Helle was the first SOE-operation to establish two-ways contact between Norway and the British and Norwegian authorities in London. For most of 1941, only one other SIS transmitter was active in Norway. In January 1942, Odd Starheim and Andreas Fasting were also the first SOE agents to be parachuted over Norway. Cheese made early contacts with the organisation in Oslo which later became Milorg. Cheese had port-spies in Stavanger and Kristiansand and close contact with people in the oil companies and airports. In addition, the organisation had a well-functioning courier system from Oslo to Stavanger, and all routes led to Tor Njaa and then to Tomstad and Starheim at Helle. The heroes are known, but in this network, there are still many unknown names. Cheese reported on the shipping traffic along the coast, the construction of German military facilities, the oil supplies in the country, the movement of military forces and the political development in the country. Two of these topics are presented here: the bombing of Sola airport and the preparation of operation Barbarossa.

On the radio beacon technique for refinement the orbit of an asteroid

Приводятся аргументы в пользу неизбежной интенсификации полетов к астероидам. Это обусловлено ростом внимания к проблеме астероидно-кометной опасности, а также быстрым ростом интереса к освоению астероидных ресурсов. Массовость полетов ставит задачу оптимизации технологии уточнения параметров движения астероидов. Метод радиопередатчика (маяка), размещенного на околоастероидной орбите, позволяет уточнить положение астероида по сравнению с обычными средствами на 2-3 порядка. Отработка такой возможности была заложена в космическом проекте «Апофис», который ранее предлагался для включения в Федеральную космическую программу, а сейчас может быть частично реализован в рамках проекта «Бумеранг». Arguments are given in favor of the inevitable intensification of flights to the asteroids. This is due to the growing attention to the problem of asteroid/comet hazard, as well as the rapid growth of interest in exploration of asteroid resources. The massive flights require an optimal technology for refining the motion parameters of asteroid. The method of a radio transmitter (beacon) placed into a near-asteroid orbit makes it possible to refine the position of the asteroid by 2-3 orders of magnitude in comparison to conventional techniques. Working out this possibility was laid down in the “Apophis” space project, which was previously proposed for inclusion in the Federal space program, and now can be implemented in the “Boomerang” project.