Nokia Mobile Phones Limited

Timo Saarnimo

Ari Leman

Mikko Pesola

Veli-Matti Valimaa

Mika E Niemio

Control circuitry for maintaining the magnitude of an RF signal from an RF signal amplifier at a predetermined level includes a detector which is supplied with a signal indicative of the power level of the output from the amplifier and outputs a signal which is dependant upon the input signal. A detector (100) is provided with a negative feedback loop (200) which supplies a biasing voltage Vb to the input of the detector, whereby the biasing voltage Vb decreases if the magnitude of the signal (P) input and hence the output signal (Vr), increases, thus serving to decrease the output voltage (Vr), and vice versa. This has the advantage of increasing the dynamic range of the detector.

Control circuitry for an RF signal amplifier

A frame construction for a radio telephone or the operating device of a radio telephone. The radio telephone comprises a frame on which printed circuit boards containing telephone electronics are secured on both sides of a substantially flat, electrically conductive frame plate. The frame plate together with ground foils of the printed circuit boards form EMI-shielding for the components located on the sides of the printed circuit boards which face the frame plate. The frame plate preferably has a raised edge to which a printed circuit board is secured. Radio telephone housing parts are located on the two sides of the frame plate to form the radio telephone housing.

Electromagnetic interference shielding construction in a radio telephone

A cooling structure for a high frequency power transistor is mounted on a circuit board where heat generated by the transistor is conducted from the semiconductor material through the collector conductor. A metal piece, which is larger than the collector conductor and sized to the requirements of heat removal through the collector conductor, contacts the collector conductor or an extension. The metal piece is solidly attached to a conductor strip formed on the circuit board. Heat is dissipated from the exposed surface of the metal piece to the ambient air and by conduction to the circuit board.

Thermally conductive bar cooling arrangement for a transistor

The invention relates to an antenna switch for radio telephones, which are provided with an extendible external antenna (1) and a built-in internal antenna (2). The antenna switch comprises a microswitch (4) having a switch arm (6) and a press switch (5). The antenna switch accomplishes the switching-on of the microswitch (4), whereupon the signal route is connected with the internal antenna (2). Respectively, when the external antenna (1) is moved in the reverse direction, the signal route is connected with the external antenna (1). The switch arm (6) is in direct contact with the external antenna (1) so that the contact accomplishes the switching-on of the microswitch (4), when the external antenna (1) is in a partly pushed-in position. The switch arm (6) is situated in close vicinity to the lowest part (15) of the external antenna (1) when the external antenna (1) is in its extended extreme position.

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Salo, Finland

Timo Saarnimo