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Method and system for demodulating frequency shift keying modulation signal

A modulation signal and frequency shift keying technology, which is applied in the modulation carrier system, frequency modulation carrier system, transmission system, etc., can solve the problems of unsuitable error correction coding and bit error rate, low transmission power, and difficult receiver sensitivity , to achieve the effect of reducing complexity, low bit error rate and high sensitivity

Active Publication Date: 2018-04-27
NATIONZ TECH INC
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The present invention provides a demodulation method and system for frequency shift keying modulated signals, aiming to solve the problem of low transmission power, compatibility with multiple data transmission rates and modulation indices, and inapplicable correction in the field of short-distance wireless communication applications. Under the premise of wrong coding and bit error rate, it is difficult to improve the sensitivity of the receiver

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  • Method and system for demodulating frequency shift keying modulation signal
  • Method and system for demodulating frequency shift keying modulation signal
  • Method and system for demodulating frequency shift keying modulation signal

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Embodiment 1

[0069] Such as figure 2 As shown, this embodiment proposes a method for demodulating a frequency shift keying modulated signal, the method comprising:

[0070] S1. Process the data sent by the external radio frequency system to obtain I / Q data of two intermediate frequency frequencies;

[0071] S2. Perform DC elimination processing on the I / Q data to remove the DC offset;

[0072] S3. The I / Q data processed by the DC elimination process is subjected to down-conversion processing and frequency offset compensation through the numerical control oscillator, so that the I / Q signal reaches zero intermediate frequency;

[0073] S4. Limit the out-of-band noise through low-pass filtering of the zero-IF I / Q data, and convert it into phase data after time-to-phase conversion;

[0074] S5. Limit the out-of-band noise of the phase data through low-pass filtering, and generate a bit code stream after differential subtraction and judgment operation. The bit code stream data includes J bit...

Embodiment 2

[0098] Such as Figure 6 As shown, this embodiment proposes a demodulation system of a frequency shift keying modulated signal, and the system includes:

[0099] The raw data processing module is used to process the data sent by the external radio frequency system to obtain I / Q data of two intermediate frequency frequencies;

[0100] The DC elimination module is used to perform DC elimination processing on the I / Q data to remove the DC offset;

[0101] The down-conversion processing module is used to perform down-conversion processing and frequency offset compensation on the I / Q data processed by the DC elimination through the numerical control oscillator, so that the I / Q signal reaches zero intermediate frequency;

[0102] The data conversion module is used to limit the out-of-band noise of the zero-IF I / Q data through the pre-demodulation filter, and convert the time phase into phase data;

[0103] The code stream generation module is used to pass the phase data through th...

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Abstract

The invention discloses a method and a system for demodulating a frequency shift keying modulation signal, and relates to the field of frequency shift keying modulation and demodulation. The method comprises the following steps of processing data sent by an external radio frequency system to obtain two paths of intermediate-frequency I / Q data, and removing direct current offsets; carrying out zerointermediate frequency processing through a numerically controlled oscillator; limiting out-of-band noise of zero-intermediate-frequency I / Q data through low-pass filtering, and becoming phase data after time phase conversion is carried out; limiting out-of-band noise of the phase data through low-pass filtering, and generating a bit code stream after differential subtraction and decision operation; comparing the generated bit code stream with an address code, and when the number of comparison results is smaller than a preset maximum number, outputting frame synchronization pulse; after the bit code stream is subjected to frequency offset calculation, outputting a frequency offset code; and after the output frequency offset code is demodulated, outputting a final demodulation result bit code stream and carrying out clock synchronization processing simultaneously. The method and the system are suitable for frequency shift keying modulation and demodulation.

Description

technical field [0001] The invention relates to the field of frequency shift keying modulation and demodulation. Background technique [0002] Different modulation and demodulation technologies have different energy utilization efficiencies to adapt to different application environments. Due to the short communication distance, short-distance wireless communication requires low cost, low complexity, and low power consumption, so simple and effective modulation and demodulation methods are generally used, including ASK (amplitude shift keying), PSK (phase shift keying) , FSK (Frequency Shift Keying) and so on. In the above-mentioned conventional modulation and demodulation technology, the carrier phase will change abruptly at the moment of data change, resulting in a large side lobe in the frequency spectrum of the modulated signal outside the main lobe, forming interference to adjacent channels. Although the reband filter can filter out the side lobe other than the main lo...

Claims

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Application Information

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IPC IPC(8): H04L27/14
CPCH04L27/14H04L27/142
Inventor 韩路赵辉张毅
Owner NATIONZ TECH INC
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