Multipath diversity spread spectrum receiver

An automatic gain control apparatus for a radio receiver comprising, in cascade arrangement:

• a variable gain controlled amplifier;
• detector means for detecting a spread spectrum signal and to provide a stream of correlation pulses that relate to transmitted data;
• integrator means for performing decision directed coherently integration or the stream of correlation pulses including;
• normalizer means for normalizing the correlation pulses to obtain a stream of normalized pulses;
• first summing means for summing the normalized pulses with a stream of output pulses to obtain a stream of combination pulses,
• delay register means for delaying the stream of combination pulses one symbol period to provide the stream of output pulses, and
• feedback path means for connecting the stream of output pulses to the summing means;
• second summing means for performing a parallel summation of the contents of the delay register to obtain a first output signal;
• and
• means for connecting the first output signal to said variable gain controlled amplifier whereby the variable gain controlled amplifier adjusts its gain in response to the first output signal.

A method of automatically adjusting a signal plus noise, comprising:

• controlling the gain of a variable gain amplifier with a subsequent generated error signal;
• detecting the spread spectrum signals and providing a stream of correlation pulses that relate to transmitted data;
• decision directed coherently integrating the stream of correlation pulses including the steps of:
• normalizing the stream of correlation pulses to obtain a stream of normalizing pulses,
• summing each member of the stream of normalized pulses with a corresponding member of a stream of output pulses to obtain a stream of combination pulses,
• delaying each member of the stream of combination pulses one symbol period to obtain the stream of output pulses thereby, and
• decoding the transmitted data from the output pulses to obtain a stream of detected data symbols.

A multipath diversity spread spectrum receiver for receiving spread spectrum signals, comprising:

• detector means for detecting the spread spectrum signals and to provide a first stream of correlation pulses and a second stream of correlation pulses that has a quadrature relationship with the first stream of correlation pulses and each stream of correlation pulses relates to transmitted data;
• integrator means for decision directed coherently integrating the first stream of correlation pulses including:
• first multiplier means for multiplying the first stream of correlation pulses with a first stream of data symbols to obtain a first stream of combination pulses,
• delay register means for delaying each member of the first stream of combination pulses one symbol period to provide a first stream of output pules, and
• normalizer means for normalizing the first stream of output pulses to obtain a stream of normalized pulses,
• first data detector means for decoding a first phase of transmitted data from the stream of normalized pulses and the first stream of correlation pulses to obtain a first stream of data symbols;
• and
• second data detector means for decoding a second phase of transmitted data from the stream of normalized pulses and the second stream of correlation pulses to obtain a second stream of data symbols.

A multipath diversity spread spectrum receiver for receiving spread spectrum signals, comprising:

• detector means for detecting the spread spectrum signals and to provide a first stream of correlation pulses and a second stream of correlation pulses which has a quadrature relationship with the first stream of correlation pulses and each stream relates to the transmitted data;
• integrator means for decision directed coherently integrating the first stream of correlation pulses including;
• first time delay means for delaying the first stream of correlation pulses one symbol period to obtain a first stream of delayed pulses,
• first multiplier means for multiplying the first stream of delayed pulses with a first stream of data symbols to obtain a first stream of product pulses,
• second time delay means for delaying the second stream of correlation pulses one symbol period to obtain a second stream of delayed pulses,
• second multiplier means for multiplying the second stream of delayed pulses with a second stream of data symbols to obtain a second stream of product pulses,
• first summing means for summing the first stream of product pulses with the second stream of product pulses to obtain a stream of combination pulses,
• delay register means for delaying each member of the stream of combination pulses one symbol period to provide a stream of output pulses, and
• normalizer means for normalizing the first stream of output pulses to obtain a stream of normalized pulses;
• first data detector means for decoding a first phase of transmitted data from the stream of normalized pulses and the first stream of correlation pulses to obtain a first stream of data symbols;
• second detector means for decoding the second phase of transmitted data from the stream of normalized pulses and the second stream of correlation pulses to obtain a second stream of data symbols;
• first feedback means for connecting the first stream of data symbols to the first multiplier means;
• and
• second feedback for connecting the second stream of data symbols to the second multiplier means.