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An FSK modulation and demodulation method based on pulse width isometric mechanism

A modulation method and demodulation method technology, applied in the field of FSK modulation and demodulation with long mechanism, can solve the problems of reducing the decoding success rate and increasing the circuit complexity, so as to simplify the hardware modulation transmission coupling circuit, avoid the complexity, The effect of reducing the overall cost

Active Publication Date: 2014-11-19
CHANGZHOU INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This brings great inconvenience to the FSK communication of smart appliances with high-speed single-chip microcomputer or DSP as the main control device, or increases the complexity of the circuit, or reduces the success rate of decoding

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  • An FSK modulation and demodulation method based on pulse width isometric mechanism
  • An FSK modulation and demodulation method based on pulse width isometric mechanism
  • An FSK modulation and demodulation method based on pulse width isometric mechanism

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Embodiment Construction

[0039] The present invention will be further explained below according to the drawings and specific embodiments of the specification.

[0040] Such as figure 1 As shown, to modulate "0", the adopted symbol width t 0 =11.25us, number of symbols n=9, modulation frequency f 0 It is approximately equal to 88.88KHz, and the total modulation time T is equal to 101.25us; to modulate "1", the used symbol width t 0 =10.125us, number of symbols m=10, modulation frequency f 0 It is approximately equal to 98.76KHz, and the total modulation time T is equal to 101.25us. The modulation center frequency is about 93.56KHz. The effective data rate of FSK can reach 9.8Kbit / s.

[0041] A kind of FSK modulation method based on pulse width equal length mechanism, the step comprises:

[0042] 1. Timer initialization

[0043] 1) Take out a byte to be modulated and sent, and set the "number of byte cycles A" to 8 bits (times);

[0044] 2) Determine the highest bit of the byte to be modulated a...

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Abstract

The present invention discloses an FSK modulation and demodulation method based on pulse width isometric mechanism. The method includes: modulating n pulses with the frequency of f0, and the cycle of t0 regarding "0", and modulating m pulses with the frequency of f1, and the cycle of t1 regarding "1", so that the total modulation width T0 of "0" equals to the total modulation width T1 of "1". In the field of low speed carrier communication, the present invention directly modulate and demodulate using a high speed single chip, DSP, etc. as master control devices, which can effectively increase success rate of demodulation identification under the premise of remarkably reducing the cost.

Description

technical field [0001] The invention relates to the field of digital information transmission, in particular to an FSK modulation and demodulation method based on a pulse width and equal length mechanism. Background technique [0002] FSK (Frequency-Shift Keying, frequency-shift keying) is a digital modulation technology that uses carrier frequency changes to transmit digital information. It has the characteristics of easy realization, good performance of anti-noise and anti-attenuation. It has been widely used in power carrier communication. Such as civilian smart meter reading system, telecontrol information sending and receiving in power grid, telemetry and remote control transmission in mine system, etc. [0003] The most commonly used method of FSK is to modulate the binary numbers 1 and 0 into f 1 with f 2 Two dual frequency FSK systems with different frequencies. The modulated frequency is much higher than the grid frequency. In the FSK system, "modulation" is r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/10
CPCH04L27/1563
Inventor 吴志祥高波杜玉华黄亮
Owner CHANGZHOU INST OF TECH