Telefonaktiebolaget Lm Ericsson (publ)

Anders W Jarleholm

Dan Anders Lindqvist

Thomas Ostman

Leif T Ostman

A method and apparatus in a radio telecommunications system for converting data from a first sample rate to a second sample rate such that the first and second sample rates are preferably within 10% of each other are disclosed. An input buffer receives a plurality of data groupings at a first sample rate. A spline filter utilizes the input data along with a phase difference between input and output data to calculate a third order spline function and an output time for the input data. This information is used to convert the input data at the first sample rate to output data at a second sample rate. The output data is buffered within an output buffer until transmitted to an associated base band unit.

Method and apparatus for rate conversion

A device and method are provided for fully realizing the precision gained internally from a conventional digital signal processor by generating a feed forward automatic gain control (AGC) signal. The feed forward AGC bit is indicative of the output of the digital signal processor being multiplied by a gain factor when the output from the digital filter included in the digital signal processor is below a threshold value. When the feed forward AGC signal is received by an inphase and quadrature (I/Q)-to-(logR/.phi.) converter connected to the digital signal processor, a corresponding value is subtracted from the radius component of the signal calculated by the (I/Q)-to-(logR/.phi.) converter. Because conventional digital signal processors have 16 IO bits, the feed forward AGC signal allows an input signal with a dynamic range and precision exceeding 16 bits to be transferred from the digital signal processor without loosing performance. As a result, a digital signal processor with a fewer number of IO bits than is nominally required for the precision and dynamic range of the output signal is implemented.

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Sollentuna, Sweden

Anders W Jarleholm