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An integrated circuit including a demodulating finger is provided for variably extracting symbols in the demodulation process of spread spectrum signals. Following the uncovering of an information channel sample stream, partial I and Q accumulations are supplied at a rate of one partial I and Q accu

An integrated circuit including a demodulating finger is provided for variably extracting symbols in the demodulation process of spread spectrum signals. Following the uncovering of an information channel sample stream, partial I and Q accumulations are supplied at a rate of one partial I and Q accumulation per four PN chips. A dot product operation is then performed upon these partial I and Q accumulations using a pilot estimate, and the resulting partial symbols are accumulated in a second process, where the soft symbols can be selectively supplied with a symbol period in the range from 4 to 2048 PN chips. In this manner, the symbol accumulation process can be made to work with a wide variety of information channel symbol rates. A method for partially accumulating soft symbols, both before and after the dot product operation, is also provided.

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1. In a spread spectrum communications integrated circuit including a demodulating finger for extracting soft symbols from a sample stream including a plurality of information channels, the demodulating finger comprising:at least one finger channel each finger channel including:a dot product unit ha

1. In a spread spectrum communications integrated circuit including a demodulating finger for extracting soft symbols from a sample stream including a plurality of information channels, the demodulating finger comprising:at least one finger channel each finger channel including:a dot product unit having a first input to accept partial I and Q accumulations, a second input to accept a pilot estimate, and an output to supply partial symbols; anda variable accumulator having an input connected to the dot product unit output to accept partial symbols, a second input to accept accumulation period commands, and an output to supply soft symbols accumulated at a rate responsive to the accumulation period commands. 2. The demodulating finger of claim 1 in which spread spectrum signals are spread with a PN code at a PN chip rate; andwherein the variable accumulator supplies soft symbols with a symbol period in the range between 4 and 6,384 PN chips. 3. The demodulating finger of claim 1 in which spread spectrum signals are spread with a PN code at a PN chip rate; andwherein the variable accumulator supplies soft symbols with a symbol period in the range between 4 and 2048 PN chips. 4. The demodulating finger of claim 1 further comprising:a first accumulator having a first input to accept an uncovered sample stream and an output to supply partial I and Q accumulations. 5. The demodulating finger of claim 4 in which the spread spectrum signals are spread with a PN code at a PN chip rate; andwherein the first accumulator supplies partial I and Q accumulations at a rate of one partial I and Q accumulation per four PN chips. 6. The demodulating finger of claim 5 in which the spread spectrum signals include I and Q channels; andwherein the first accumulator input accepts uncovered sample stream I and Q channels and the output supplies partial accumulations of the I and Q channels. 7. The demodulating finger of claim 6 wherein the dot product unit first input accepts partial I and Q accumulations and the second input accepts an I and Q channel pilot estimate, the dot product unit performing a dot product operation upon the partial I and Q accumulations, using the pilot estimate, to supply partial symbols as scalar values. 8. The demodulating finger of claim 7 wherein the second accumulator accepts the partial symbols and supplies soft symbols at a rate responsive to the accumulation period commands. 9. The demodulating finger of claim 4 wherein each finger channel further includes:an uncovering unit having a first input to accept a despread sample stream, a second input to accept a Walsh code, and an output connected to the first accumulator input to supply the uncovered sample stream. 10. In a spread spectrum communications integrated including a demodulating finger for extracting soft symbols from a sample stream including a plurality of information channels, the demodulating finger comprising:a plurality of finger channels, each finger channel including:a first accumulator having a first input to accept an uncovered sample stream and an output to supply partial I and Q accumulations;a dot product unit having a first input connected to the first accumulator output to accept partial I and Q accumulations, a second input to accept a pilot estimate, and an output to supply partial symbols; anda variable accumulator having an input connected to the dot product unit output to accept partial symbols, a second input to accept accumulation period commands, and an output to supply soft symbols at a rate responsive to the accumulation period commands. 11. In a spread spectrum communications integrated circuit including a demodulating finger, a method for extracting soft symbols from a sample stream including a plurality of information channels, the method comprising:performing a dot product operation upon partial I and Q accumulations;in response to performing the dot product operation upon the partial I and Q accumulations, supplying partial symbols ;selecting an accumulation period;accumulating the partial symbols at a rate responsive to the selected accumulation period; andin response to accumulating the partial symbols, supplying soft symbols. 12. The method of claim 11 in which spread spectrum signals are spread with a PN code at a PN chip rate; andwherein selecting the accumulation period includes selecting an accumulation period includes selecting an accumulation period to supply soft symbols with a symbol period in the range between 4 and 16,384 PN chips. 13. The method of claim 11 in which spread spectrum signals are spread with a PN code at a PN chip rate; andwherein selecting the accumulation period includes selecting an accumulation period to supply soft symbols with a symbol period in the range between 4 and 2048 PN chips. 14. The method of claim 11 further comprising:preceding the performing of the dot product operation upon the partial I and Q accumulations, accepting an uncovered sample stream;accumulating the uncovered sample stream at a first accumulation rate; andin response to accumulating the uncovered sample stream, supplying the partial I and Q accumulations. 15. The method of claim 14 in which spread spectrum signals are spread with a PN code at a PN chip rate; andwherein accumulating the uncovered sample stream at the first accumulation rate includes supplying partial I and Q accumulations at a rate of one partial I and Q accumulation per four PN chips. 16. The method of claim 14 further comprising:preceding the accepting of the uncovered sample stream, accepting a despread sample stream;uncovering the despread sample stream; andsupplying the uncovered sample stream. 17. The method of claim 16 in which spread spectrum signals include I and Q channels; andwherein accumulating the uncovered sample stream at the first accumulation rate includes accumulating uncovered sample stream I and Q channels; andwherein supplying partial I and Q accumulations includes supplying partial accumulations of the I and Q channels. 18. The method of claim 17 further comprising:accepting an I and Q channel pilot estimate; andwherein performing a dot product operation upon the partial I and Q accumulations includes using the I and Q channel pilot estimate as a reference; andwherein supplying partial symbols includes supplying scalar partial symbols. 19. The method of claim 18 wherein accumulating the partial symbols at a rate responsive to the selected accumulation period includes accumulating scalar partial symbols. 20. The method of claim 16 further comprising:accepting a Walsh code; andwherein uncovering the despread sample stream includes using the Walsh code to uncover the despread sample stream.