Abstract: A polarity protection circuit contains a metal oxide semiconductor field effect transistor (FET) that pets its control voltage via an electrical connection from supply voltage lines and a transistor that pets its control voltage via another connection from the supply voltage lines. When a supply voltage has a wrong polarity the FET is in a non-conducting state. If in the supply voltage lines during normal operation there occurs a short circuit that tends to chance a direction of the current, the transistor rapidly discharges a gate charge of the FET, and the current flow in the wrong direction is prevented.

Abstract: The invention relates to a polarity protection circuit, which is used in a power supply arrangement where a power supply is connected via supply voltage lines to a load. The polarity protection circuit further contains a first protective semiconductor switch, which is a metal oxide semiconductor field effect transistor, and which gets its control voltage via a certain connection from said supply voltage lines. The second semiconductor switch is a transistor, which also gets its control voltage via a certain connection from said supply voltage lines. If the supply voltage has the wrong polarity the first protective semiconductor switch is kept in the non-conducting state. If for instance in the supply voltage lines during normal operation there occurs a short circuit, which tends to change the direction of the current, then the transistor rapidly discharges the gate charge of the first protective semiconductor switch, and the current flow in the wrong direction is prevented.

Abstract: A method of determining a grade of service provided for a mobile station by a mobile telephone system including a network part, a mobile station and a bi-directional radio link between the network part and the mobile station. The method comprises the network part assigning a service class for the mobile station based on a grade of service guaranteed by the mobile telephone system to the mobile station and conditions of the mobile telephone system. The conditions comprise transmission capacity and at least one other preselected variable representing features of the mobile telephone system and its use.

Abstract: The invention relates to a receiving method and a receiver. In the method, in order to remove interference of a received composite signal, narrowband interfering signal estimates corresponding to the interfering signals are subtracted from a narrowband composite signal. The narrowband interfering signal estimates are generated in the interference cancellation primitives of the receiver by multiplying a detected bit of the interfering signal by a cross correlation and a channel estimate of spreading codes.