US 2002/0163957 A1 · Code division multiple access (CDMA) code timing tracking apparatus

Abstract

Disclosed is a CDMA (Code Division Multiple Access) code timing tracking apparatus capable of exact code timing synchronization without regard to signal gain change by normalizing signal gain to synchronize code timing. The CDMA code timing tracking apparatus correlates each code generated from a PN code generator, which generates on-time code, early code being faster than the on-time code and late code being later than the on-time code, with CDMA signal, low-pass filters output signal of a plurality of correlators with first to third low-pass filters and quantizes output signal of the first low-pass filter. Furthermore, the CDMA code timing tracking apparatus subtracts output signal of the third low-pass filter from output signal of the second low-pass filter, generates difference signal, divides the difference signal by output signal of a quantizer and generates the resulted value as error signal to compensate error, thereby obtaining exact CDMA code timing tracking without regard to the size of input signal.

Claims13

Dependent claims

A CDMA (Code Division Multiple Access) code timing tracking apparatus comprising:

a PN code generator for generating on-time code, early code, which is faster than the on-time code, and late code, which is later than the on-time code;
a first correlator for correlating the on-time code generated from the PN code generator with baseband CDMA signal, which is input;
a second correlator for correlating the early code generated from the PN code generator with the baseband CDMA signal;
a third correlator for correlating the late code generated from the PN code generator 101 with the baseband CDMA signal;
first to third low-pass filters for low-pass filtering output signal of the first to third correlators respectively;
a quantizer for quantizing the output signal of the first low-pass filter;
a subtracter for subtracting the output signal of the third low-pass filter from the output signal of the second low-pass filter and generating difference signal;
a divider for dividing the output signal of the subtracter by the output signal of the quantizer and generating its result value as error signal;
a fourth low-pass filter for low-pas filtering the output signal of the divider;
and
a voltage-to-current converter for converting the output signal of the fourth low-pass filter into current and transmitting it to the PN code generator.

8 more elements

A CDMA (Code Division Multiple Access) code timing tracking apparatus comprising:

a PN code generator for generating on-time code, early code, which is faster than the on-time code, and late code, which is later than the on-time code;
a first correlator for correlating the on-time code generated from the PN code generator and CDMA immediate frequency signal, which is input;
a second correlator for correlating the early code generated from the PN code generator and the CDMA immediate frequency signal;
a third correlator for correlating the late code generated from the PN code generator and the CDMA immediate frequency signal;
first to third band-pass filters for band-pass filtering output signal of the first to third correlators respectively;
first to third square units for squaring the output signal of the first to third band-pass filters respectively;
a quantizer for quantizing output signal of the square unit;
a subtracter for subtracting the output signal of the third square unit from the output signal of the second square unit and generating difference signal;
a divider for dividing the output signal of the subtracter by the output signal of the quantizer and generating its result value as error signal;
a low-pass filter for low-pas filtering the output signal of the divider;
and
a voltage-to-current converter for converting the resulted value filtered in the low-pass filter into current and transmitting to the PN code generator.

9 more elements

A CDMA (Code Division Multiple Access) code timing tracking apparatus comprising:

a PN code generator for generating on-time code, early code, which is faster than the on-time code, and late code, which is later than the on-time code;
a first correlator for correlating the on-time code generated from the PN code generator with real part signal and imaginary part signal of baseband CDMA signal, which is input, respectively;
a second correlator for correlating the early code generated from the PN code generator with real part signal and imaginary part signal of the baseband CDMA signal respectively;
a third correlator for correlating the late code generated from the PN code generator with real part signal and imaginary part signal of the baseband CDMA signal respectively;
first to third low-pass filters for low-pass filtering the output signal of the first to third correlators respectively;
a square unit for squaring the output signal of the first low-pass filter;
a quantizer for quantizing the output signal of the square unit;
a phase detector for detecting the phase difference between the output signal of the second and third low-pass filters;
a divider for dividing the output signal of the phase detector by the output signal of the quantizer and generating its result value as error signal;
a fourth low-pass filter for low-pass filtering the output signal of the divider;
and
a voltage-to-current converter for converting the output signal of the fourth low-pass filter and transmitting to the PN code generator to compensate error.

9 more elements

Dependencies are inferred from the claim text.

Code division multiple access (CDMA) code timing tracking apparatus

Life of this patent

Code division multiple access (CDMA) code timing tracking apparatus

Life of this patent

Abstract

Claims13