Correlation circuit for spread spectrum
First Claim
1. A correlation circuit for spread spectrum communication for obtaining a correlation output from a spectrum-spread received signal, said circuit comprising:
- an A/D converter for converting said received signal to a digital signal from an analog signal and sampling the signal;
a memory for storing an output from said A/D converter;
an input signal register, having a variable transfer speed of a shift, for shifting and outputting the input signal from said memory at a specified speed;
spread code registers, prepared for a necessary number of users, for shifting and outputting a generated spread code;
a sum of products calculator for multiplying and adding the input signal outputted from said input signal register and the spread code outputted from said spread code register at a specified number of times said sampling speed; and
a controller for;
controlling the transfer speed of the shift of one sample in said input signal register in order to hold a sufficient time for completing calculation of a sum of products with respect to all a plurality of users in said sum of products calculator, when the plurality of users more than a specified number of users exist in the same phase of the input signal from said memory;
subsequently controlling and setting said transfer speed to be higher than said specified speed before compensating for a delay time within one symbol, when the users less than said specified number of users exist in the same phase; and
controlling and selecting the spread code to be outputted to said sum of products calculator in accordance with the number of users in the same phase.
1 Assignment
0 Petitions
Accused Products
Abstract
There is disclosed a correlation circuit for spread spectrum communication, which can demodulate users having superposed demodulation phases and equaling or exceeding a sum of products calculation processing ability without enlarging a constitution. When a plurality of users more than a specified number exist in the same phase of the input signal from a memory, a controller controls a transfer speed of a shift of one sample in an input signal register in order to hold a sufficient time for completing calculation of a sum of products with all the plurality of users in a sum of products calculator in the correlation circuit for spread spectrum communication.
66 Citations
20 Claims
-
1. A correlation circuit for spread spectrum communication for obtaining a correlation output from a spectrum-spread received signal, said circuit comprising:
-
an A/D converter for converting said received signal to a digital signal from an analog signal and sampling the signal;
a memory for storing an output from said A/D converter;
an input signal register, having a variable transfer speed of a shift, for shifting and outputting the input signal from said memory at a specified speed;
spread code registers, prepared for a necessary number of users, for shifting and outputting a generated spread code;
a sum of products calculator for multiplying and adding the input signal outputted from said input signal register and the spread code outputted from said spread code register at a specified number of times said sampling speed; and
a controller for;
controlling the transfer speed of the shift of one sample in said input signal register in order to hold a sufficient time for completing calculation of a sum of products with respect to all a plurality of users in said sum of products calculator, when the plurality of users more than a specified number of users exist in the same phase of the input signal from said memory;
subsequently controlling and setting said transfer speed to be higher than said specified speed before compensating for a delay time within one symbol, when the users less than said specified number of users exist in the same phase; and
controlling and selecting the spread code to be outputted to said sum of products calculator in accordance with the number of users in the same phase. - View Dependent Claims (2, 3, 5, 6, 7, 9, 10, 11, 13, 14, 15, 17, 18, 19)
-
-
4. A correlation circuit for spread spectrum communication for obtaining a correlation output from a spectrum-spread received signal, said circuit comprising:
-
a plurality of A/D converters for converting said plurality of received signals to digital signals from analog signals and sampling the signals;
a memory for input signals in which a speed of an output timing is variable and which stores outputs from said plurality of A/D converters and outputs the selected input signal at the speed of a specified timing;
a memory for spread codes which stores a plurality of types of spread codes and outputs the selected spread code;
a sum of products calculator for multiplying and adding the input signal selectively outputted from said memory for the input signals and the spread code selectively outputted from the memory for the spread codes at a specified number of times a sampling speed; and
a controller for;
controlling a timing for outputting the input signal stored in said memory for the input signals and the spread code stored in said corresponding memory for the spread codes to said sum of products calculator;
controlling the speed of the output timing from said memory for the input signals in order to hold a sufficient time for completing calculation of a sum of products with respect to all a plurality of users in said sum of products calculator, when the plurality of users more than said specified number of users exist in the same phase of the input signal inputted in said memory for the input signals;
subsequently controlling and setting the speed of the output timing from said memory for the input signals to be higher than the speed of said specified timing before compensating for a delay time within one symbol, when the users less than said specified number of users exist in the same phase; and
controlling and selecting the spread code to be outputted to said sum of products calculator in accordance with the number of users in the same phase. - View Dependent Claims (8, 12, 16, 20)
-
Specification