Low-IF Photon Broadband Radio Frequency Reception Method Based on k-k Detection

Abstract

The invention discloses a low-intermediate-frequency photon broadband radio frequency receiving method based on K-K detection, and the invention relates to the fields of optical communication and microwave technology. The method is shown in the accompanying drawings, including the laser LD, erbium-doped fiber amplifier EDFA1, polarization controller PC, dual parallel Mach-Zehnder modulator DPMZM, signal generator SG, erbium-doped fiber amplifier EDFA2, optical filter OF, photodetector PD, analog-to-digital converter ADC and digital signal processor DSP. Use DPMZM to suppress carrier double-sideband modulation on broadband high-frequency radio frequency signals and high-frequency local oscillator signals respectively, and use DSP to use K-K detection algorithm after direct detection by a single PD. The beat frequency interference between signals generated by the detection can convert the broadband high-frequency radio frequency signal to a lower intermediate frequency and restore the useful signal. This scheme only uses one modulator and PD, and both the radio frequency signal and the local oscillator signal use suppressed carrier double sideband Modulation, simple structure.

Description

technical field [0001] The invention relates to the technical fields of optical communication and microwave technology, and mainly relates to microwave signal photonics broadband signal frequency conversion in optical communication technology. Background technique [0002] The radio frequency receiver is an important part of the electronic system. Compared with the traditional radio frequency technology, the characteristics of the microwave photonic radio frequency receiver, such as low loss, large bandwidth and anti-electromagnetic interference, have gradually been applied and developed, such as broadband wireless communication and electronic countermeasures. fields etc. [0003] An important part of the RF receiver is frequency down-conversion, by mixing the high-frequency RF signal and the high-frequency local oscillator signal to generate a lower-frequency IF signal, which can then be sampled by a lower-rate analog-to-digital converter. Usually, the microwave photon rad...

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Problems solved by technology

However, this will increase the complexity of the entire system

Alternatively, the 90-degree optical hybrid coupler can be replaced by a polarization controller and a polarization beam splitter to achieve quadrature mixing, but since the polarization of light is very sensitive to external vibrations, the stability of the system will be greatly reduced

In addition, there will also be multi-channel length matching problems through the multi-channel method, which will also increase the complexity of the system.

[0006] In the self-coherent detection scheme using K-K detection, that is, the Kramer-Crangney algorithm, the optical carrier is suppressed by carrier single-sideband modulation through high-frequency radio frequency signals and high-frequency local oscillator signals, which can also eliminate the beating frequency between signals Interference, but SSB modulation requires quadrature processing of radio frequency signals, which is dependent on the frequency of radio frequency signals, and it is also difficult to quadrature processing of broadband signals, thus affecting the operating frequency range of the system and the bandwidth of the receiver

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