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Frequency hooping communication device with simple structure

A technology of frequency hopping communication and frequency hopping frequency, applied in the direction of electrical components, modulation, angle modulation components, etc., can solve the problem of difficult to control the frequency offset correction circuit and so on

Inactive Publication Date: 2003-09-24
NEC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, it is difficult to control the frequency offset correction circuit because there are many combinations of switch states ON / OFF

Method used

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  • Frequency hooping communication device with simple structure
  • Frequency hooping communication device with simple structure
  • Frequency hooping communication device with simple structure

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Experimental program
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Embodiment Construction

[0036] refer to Figures 1 to 3 , first, a conventional frequency hopping GFSK (Gaussian Frequency Shift Keying) communication device will be described. A GFSK communication device can be thought of as a frequency hopping GFSK modulated radio.

[0037] A conventional GFSK communication device includes a VCO (Voltage Controlled Oscillator) that changes its oscillation frequency according to the supplied input voltage. In the GFSK communication device, GFSK modulation is realized by using a voltage-controlled oscillator. In other words, the oscillation frequency of the VCO is changed by the modulation voltage (or base-band signal, or modulation signal) supplied to the VCO. This modulation voltage corresponds to the transmitted digital code.

[0038] The VCO includes a figure 1 The LC circuit of the varactor diode (with capacitance D) shown in . The oscillation frequency "F" of the VCO is given by the following equation: F = 1 / ...

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Abstract

A frequency hopping communication device has a memory for storing modulation coefficients related to the frequency hopping frequency of a carrier. Whenever the subsequent frequency hopping frequency is determined, the central processing unit (CPU) reads out one of the modulation coefficients according to the subsequent frequency hopping frequency from the memory, and supplies it to the Gaussian filter. The Gaussian filter stores the read modulation coefficient in the register, and then multiplies the supplied transmit data signal by the read modulation coefficient stored in the register to generate a modulated signal. Therefore, the modulating signal has a voltage amplitude that depends on the carrier frequency. The voltage controlled oscillator modulates a carrier with a subsequent hopping frequency with the modulation signal from the Gaussian filter and generates a transmit signal. Therefore, the transmitted signal has an approximately uniform frequency offset independent of the carrier frequency.

Description

[0001] This application claims priority from a prior Japanese Patent Application No. JP2002-064825, which is incorporated herein by reference. technical field [0002] The present invention relates to a frequency hopping spread spectrum communication device, in particular to a spread spectrum GFSK (Gaussian Frequency Shift Keying) communication device, which can maintain approximately uniform frequency deviation and has nothing to do with carrier frequency. Background technique [0003] Generally, a GFSK communication device includes a VCO (Voltage Controlled Oscillator) to generate a modulated carrier wave as a transmission signal. The VCO is not only used for modulating the carrier but also for frequency hopping of the carrier. [0004] The transmitted signal must have a frequency offset that is limited within a specified range. If the carrier frequency of the carrier is fixed, it is easy to limit the frequency deviation within the prescribed range. That is, the amplitud...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/713G01R29/06H03C3/09H04B1/7136
CPCH03C3/0958H03C3/0991
Inventor 五十岚克人
Owner NEC CORP
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