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CDMA modulation method and device thereof

A modulation method, spread spectrum modulation technology, applied in multiplex code generation, phase modulation carrier system, electrical components, etc., can solve problems such as increasing power consumption and increasing gate size

Inactive Publication Date: 2005-03-09
SHARP KK
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this way, LPF (ie square root Nyquist filter) 132 and 133 need multi-bit input, multi-bit output, multi-bit weighting and multiple taps, so there is a problem of increasing gate size and power consumption

Method used

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  • CDMA modulation method and device thereof
  • CDMA modulation method and device thereof
  • CDMA modulation method and device thereof

Examples

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Embodiment Construction

[0051] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0052] figure 1 is a block diagram showing an embodiment of the CDMA modulation circuit of the present invention. Input to the CDMA modulation circuit ( Figure 7 The secondary modulator shown) are digital signals (Di, Dq). This CDMA modulation circuit comprises: multiplier 11 and 12; The first spreading code generator 31 and 32; The second spreading code generator 33 and 34; Composite QPSK processor 13; LPF (square root Nyquist filter ) 18, 19, 20 and 21; DAC (digital-to-analog converter) 22, 23, 24 and 25; gain factor controller 35; weighting multipliers 26 and 27; and adders 28 and 29. Complex QPSK processor 13 includes multipliers 14 , 15 , 16 and 17 .

[0053] The independent digital data signals Di and Dq are spread-spectrum-modulated by the multipliers 11 and 12 with the first spread-spectrum codes Ci and Cq generated by the spread-spectrum code generators 31...

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Abstract

CDMA complex QPSK spread modulation for reducing the scale of the gate and power consumption. Digital data signals (Di, Dq) are spread-modulated by multipliers (11, 12) with first spread codes (Ci, Cq) generated by spread code generators (31, 32), and a spread modulating signal (Di.Ci) (41) and a spread modulating signal (Dq.Cq) (42) are generated. The signals (41, 42) are inputted to a complex QPSK operation unit (13), subjected to a complex QPSK operation with second spread codes (Si, Sq) generated by spread code generators (33, 34), and filtered by LPFs (18-21). Multipliers (26, 27) apply the weight of the gain factor G from a gain factor controller (63) to signals (44, 45) converted into analog values (51-54) by DAC (22-25) and including an ICH data signal (Dq).

Description

technical field [0001] The invention relates to a spread spectrum modulation method in a spread spectrum communication system and a CDMA (Code Division Multiple Access) system and a device using the method, in particular to a CDMA spread spectrum modulation method and a device using the method to realize composite QPSK (Quadrature Phase Shift Keying) spread spectrum modulation device. technical background [0002] The spread spectrum communication and CDMA (Code Division Multiple Access) system using spread spectrum communication technology have the characteristics of strong anti-multipath fading ability, high data rate, excellent communication quality and high frequency utilization. Therefore, this type of system is used as the next generation mobile The realization of communication system and multimedia mobile communication has attracted people's attention. [0003] In spread spectrum communication, the signal to be transmitted is first spread into a signal with a bandwid...

Claims

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Application Information

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IPC IPC(8): H04L27/20H04B1/707
CPCH04B2201/70707H04B1/707H04J13/12
Inventor 福元修作中井孝至荒木俊介
Owner SHARP KK
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