Demodulator device with function of frequency calibration based on adaptive equalization

A self-adaptive equalization and demodulator technology, applied in the direction of modulation and conversion balancing devices, etc., can solve the problem of weak anti-frequency offset ability, improve reliability, solve the problem of anti-frequency offset ability, and eliminate inter-symbol crosstalk. Effect

Active Publication Date: 2015-08-05
NO 54 INST OF CHINA ELECTRONICS SCI & TECH GRP
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Problems solved by technology

Usually, in microwave and other high-frequency communication systems, the frequency deviation can reach several kHz or even dozens of kHz, the traditional

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  • Demodulator device with function of frequency calibration based on adaptive equalization
  • Demodulator device with function of frequency calibration based on adaptive equalization

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[0013] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0014] Reference Figure 1 to Figure 2 The present invention is composed of A / D converter 1, digital down-conversion 2, NCO3, Costas loop 4, interpolation filter 5, timing extraction 6, adaptive equalizer 7 and power supply 8. figure 1 It is a block diagram of the electrical principle of the present invention. figure 1 Connect the line. The function of A / D converter 1 samples the received low-IF signal, converts the analog signal into a digital signal and outputs it to digital down-conversion 2. The function of digital down-conversion 2 is to multiply the low-IF signal with NCO3 Convert it into a baseband signal, and perform low-pass filtering on the baseband signal, and then output to Costas loop 4; Costas loop 4 is a decision feedback loop. The present invention directly uses the square of the sampled signal for phase detection. The Tas ring 4 removes the fr...

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Abstract

The invention discloses a demodulator device with a function of frequency calibration based on adaptive equalization, and relates to the field of wireless communication. According to the invention, a Costas loop is added at the front end of an adaptive equalizer, and a demodulator can be enabled to have a function of removing intersymbol interference during a frequency offset through the characteristic of big frequency offset resistance of the Costas loop. After the demodulator receives an outputted baseband signal after digital downconversion and low-pass filtering, the Costas loop is used at first to remove frequency offset caused by different sources of clocks at receiving and transmitting ends, and then the adaptive equalizer is used for removing the intersymbol interference between adjacent code elements. The device is characterized in that there is no need to require that the stability of clock sources at two communication ends is high, the repeatability is good and the performance is excellent, so the device is especially suitable for high-speed communication of wireless channels, such as microwave communication, scatter communication and so on.

Description

technical field [0001] The invention relates to a demodulator device based on self-adaptive equalization and having a frequency calibration function under the conditions of high-speed transmission, deep fading and large frequency deviation in the field of wireless communication. It is especially suitable for demodulation in wireless communication under conditions such as fading and large frequency deviation. Background technique [0002] For high-speed wireless communication systems, the difficulty lies in eliminating intersymbol interference and anti-large frequency offset. Usually, in microwave and other high-frequency communication systems, the frequency deviation can reach several kHz or even dozens of kHz, the traditional adaptive equalizer has weak anti-frequency deviation ability, which can only be solved by reducing the rate or improving the stability of the clock source. The demodulator based on adaptive equalization and frequency correction function has broad appl...

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Application Information

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IPC IPC(8): H03D7/14
Inventor 石柳王伟
Owner NO 54 INST OF CHINA ELECTRONICS SCI & TECH GRP
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