Nokia Corporation

Nokia Telecommunications Oy

Jari Pekkarinen

Toni Neffling

A method of setting up a linearizing circuit such as a linear power amplifier is described. According to the method, an input signal is supplied at a low, starting power level and is lowly increased during a set-up until it attains an operational level for normal use. The advantage of this is that pilot tone used in the linearizing circuit can be readily detected during set-up because its amplitude is above that of the low, starting power level of the input signal. A feed-forward linearizing system and a transmission system utilizing the technique are described.

Set-up method for a linearizing circuit

A test method in an RF communication system. In the communication system, at least one RF communication channel lies about a known carrier frequency in an RF communication band. According to the method, a diagnostic signal is introduced into a circuit to be tested, such as a linear power amplifier, the diagnostic signal having an RF diagnostic frequency lying within the communication band. The diagnostic signal is down converted to an intermediate frequency for diagnostic purposes so that DSP is simplified. The diagnostic frequency is selected based on the known carrier frequency of the communication channel so that the communication channel is not down converted as an image band with the diagnostic signal.

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Fleet, United Kingdom

Jari Pekkarinen