Code division multiple access transmitter and receiver
First Claim
1. A code division multiple access transmitter comprising:
- a primary modulator for carrying out primary modulation of transmission information, thereby generating a primary modulated I (In-phase) signal and a primary modulated Q (Quadrature) signal;
spreading code generating means for generating a spreading code which corresponds to a channel, and has a frequency higher than a rate of said transmission information;
a secondary modulator for performing spread modulation of said primary modulated I signal and said primary modulated Q signal using said spreading code, thereby outputting spread I-channel data and spread Q-channel data;
a frequency offset circuit for offsetting a center frequency of said spread I-channel data and of said spread Q channel data by a designated offset frequency, thereby outputting frequency offset data; and
a transmitting circuit for converting said frequency offset data into a transmitted signal, wherein said frequency offset circuit comprises;
a first signal generator for generating a cosine wave of a frequency corresponding to said designated offset frequency;
a second signal generator for generating a sine wave of the frequency corresponding to said designated offset frequency;
a first multiplier for multiplying said spread I-channel data by said cosine wave;
a second multiplier for multiplying said spread Q-channel data by said sine wave;
a first adder for summing an output of said first multiplier and an output of said second multiplier.
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Accused Products
Abstract
A code division multiple access transmitter and receiver that makes it possible to reduce its size by designating a spreading code and a carrier frequency in a baseband. It includes a primary modulator for performing primary modulation by transmission information, thereby producing a primary modulated I signal and a primary modulated Q signal, a spreading code generator for generating a spreading code with a frequency higher than a rate of the transmission information, a secondary modulator for spread-modulating the primary modulated I signal and Q signal by using the spreading code, thereby outputting spread I-channel data and spread Q-channel data, a frequency offset circuit for offsetting the center frequency of the spread I-channel data and Q-channel data by a designated offset frequency, thereby outputting frequency offset data, and a transmitting circuit for converting the frequency offset data into a transmitted signal.
39 Citations
12 Claims
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1. A code division multiple access transmitter comprising:
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a primary modulator for carrying out primary modulation of transmission information, thereby generating a primary modulated I (In-phase) signal and a primary modulated Q (Quadrature) signal; spreading code generating means for generating a spreading code which corresponds to a channel, and has a frequency higher than a rate of said transmission information; a secondary modulator for performing spread modulation of said primary modulated I signal and said primary modulated Q signal using said spreading code, thereby outputting spread I-channel data and spread Q-channel data; a frequency offset circuit for offsetting a center frequency of said spread I-channel data and of said spread Q channel data by a designated offset frequency, thereby outputting frequency offset data; and a transmitting circuit for converting said frequency offset data into a transmitted signal, wherein said frequency offset circuit comprises; a first signal generator for generating a cosine wave of a frequency corresponding to said designated offset frequency; a second signal generator for generating a sine wave of the frequency corresponding to said designated offset frequency; a first multiplier for multiplying said spread I-channel data by said cosine wave; a second multiplier for multiplying said spread Q-channel data by said sine wave; a first adder for summing an output of said first multiplier and an output of said second multiplier. - View Dependent Claims (4, 5)
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2. A code division multiple access transmitter comprising:
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a primary modulator for carrying out primary modulation of transmission information, thereby generating a primary modulated I (In-phase) signal and a primary modulated Q (Quadrature) signal; spreading code generating means for generating a spreading code which corresponds to a channel, and has a frequency higher than a rate of said transmission information; a secondary modulator for performing spread modulation of said primary modulated I signal and said primary modulated Q signal using said spreading code, thereby outputting spread I-channel data and spread Q-channel data; a frequency offset circuit for offsetting a center frequency of said spread I-channel data and of said spread Q channel data by a designated offset frequency, thereby outputting frequency offset data; and a transmitting circuit for converting said frequency offset data into a transmitted signal, wherein said frequency offset circuit comprises; a first signal generator for generating a cosine wave of a frequency corresponding to said designated offset frequency; a second signal generator for generating a sine wave of the frequency corresponding to said designated offset frequency; a first multiplier for multiplying said spread I-channel data by said cosine wave; a second multiplier for multiplying said spread Q-channel data by said sine wave; a first adder for summing an output of said first multiplier and an output of said second multiplier, wherein said transmitting circuit comprises a D/A converter for converting said frequency offset data into an analog signal, and a frequency converter for converting said analog signal into the transmitted signal.
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3. A code division multiple access transmitter comprising:
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a primary modulator for carrying out primary modulation of transmission information, thereby generating a primary modulated I (In-phase) signal and a primary modulated Q (Quadrature) signal; spreading code generating means for generating a spreading code which corresponds to a channel, and has a frequency higher than a rate of said transmission information; a secondary modulator for performing spread modulation of said primary modulated I signal and said primary modulated Q signal using said spreading code, thereby outputting spread I-channel data and spread Q-channel data; a frequency offset circuit for offsetting a center frequency of said spread I-channel data and of said spread Q channel data by a designated offset frequency, thereby outputting frequency offset data; and a transmitting circuit for converting said frequency offset data into a transmitted signal, wherein said frequency offset circuit comprises; a first signal generator for generating a cosine wave of a frequency corresponding to said designated offset frequency; a second signal generator for generating a sine wave of the frequency corresponding to said designated offset frequency; a first multiplier for multiplying said spread I-channel data by said cosine wave; a second multiplier for multiplying said spread Q-channel data by said sine wave; a third multiplier for multiplying said spread T-channel data by said sine wave; a fourth multiplier for multiplying said spread Q-channel signal by said cosine wave; a first adder for adding an output of said first multiplier and an output of said second multiplier; and a second adder for adding an output of said third multiplier and an output of said fourth multiplier, thereby carrying out a complex multiplication of said spread I-channel data and said Q-channel data with said cosine wave and said sine wave, and outputting frequency offset I-channel data and frequency offset Q-channel data.
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6. A code division multiple access transmitter comprising:
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a primary modulator for carrying out primary modulation of transmission information, thereby generating a primary modulated I (In-phase) signal and a primary modulated Q (Quadrature) signal; spreading code generating means for generating a spreading code which corresponds to a channel, and has a frequency higher than a rate of said transmission information; a secondary modulator for performing spread modulation of said primary modulated I signal and said primary modulated Q signal using said spreading code, thereby outputting spread I-channel data and spread Q-channel data; a frequency offset circuit for offsetting a center frequency of said spread I-channel data and of said spread Q channel data by a designated offset frequency, thereby outputting frequency offset data; and a transmitting circuit for converting said frequency offset data into a transmitted signal, wherein said frequency offset circuit comprises; a first signal generator for generating a cosine wave of a frequency corresponding to said designated offset frequency; a second signal generator for generating a sine wave of the frequency corresponding to said designated offset frequency; a first multiplier for multiplying said spread I-channel data by said cosine wave; a second multiplier for multiplying said spread Q-channel data by said sine wave; a third multiplier for multiplying said spread T-channel data by said sine wave; a fourth multiplier for multiplying said spread Q-channel signal by said cosine wave; a first adder for adding an output of said first multiplier and an output of said second multiplier; and a second adder for adding an output of said third multiplier and an output of said fourth multiplier, thereby carrying out a complex multiplication of said spread I-channel data and said Q-channel data with said cosine wave and said sine wave, and outputting frequency offset I-channel data and frequency offset Q-channel data, wherein said transmitter circuit comprises D/A converters for converting said frequency offset I-channel data and said frequency offset Q-channel data into analog signals, a quadrature modulator for quadrature-modulating a carrier by an analog I-channel signal and an analog Q-channel signal outputted from said D/A converters, and a frequency converter for converting an output signal of said quadrature modulator into the transmitted signal.
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7. A code division multiple access receiver comprising:
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a first frequency converter for frequency-converting a received signal into an IF (Intermediate Frequency) signal; a quadrature detector for converting said IF signal into an I-channel baseband signal and a Q-channel baseband signal; A/D converters for converting said I-channel baseband signal and said Q-channel baseband signal into digital signals; a second frequency converter for converting an I-channel digital signal and a Q-channel digital signal outputted from said A/D converters into signals with a zero center frequency using a local signal of a designated offset frequency, a center frequency of said I-channel digital signal and of said Q-channel digital signal outputted from said A/D converters being offset; a correlation detector for correlation-detecting output signals of said second frequency converter; and a demodulator for demodulating output signals of said correlation detector. - View Dependent Claims (8, 9, 10, 11)
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12. A code division multiple access system including a code division multiple access transmitter and a code division multiple access receiver,
said code division multiple access transmitter comprising: -
a primary modulator for carrying out primary modulation of transmission information, thereby generating a primary modulated I (In-phase) signal and a primary modulated Q (Quadrature) signal; spreading code generating means for generating a spreading code which corresponds to a channel, and has a frequency higher than a rate of said transmission information; a secondary-modulator for performing spread modulation of said primary modulated I signal and said primary modulated Q signal using said spreading code, thereby outputting spread I-channel data and spread Q-channel data; a frequency offset circuit for offsetting a center frequency of said spread I-channel data and of said spread Q channel data by a designated offset frequency, thereby outputting frequency offset data; and a transmitting circuit for converting said frequency offset data into a transmitted signal, said code division multiple access receiver comprising; a first frequency converter for frequency-converting a received signal into an IF (Intermediate Frequency) signal; a quadrature detector for converting said IF signal into an I-channel baseband signal and a Q-channel baseband signal; A/D converters for converting said I-channel baseband signal and said Q-channel baseband signal into digital signals; a second frequency converter for converting an I-channel digital signal and a Q-channel digital signal outputted from said A/D converters into signals with a zero center frequency using a local signal of a designated offset frequency, a center frequency of said I-channel digital signal and of said Q-channel digital signal outputted from said A/D converters being offset; a correlation detector for correlation-detecting output signals of said second frequency converter; and a demodulator for demodulating output signals of said correlation detector.
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Specification