Dual-channel radio frequency receiver and frequency planning method thereof

Abstract

The invention provides a dual-channel radio frequency receiver and a frequency planning method thereof. In the method, any two paths of radio frequency signals of a global navigation satellite systems with different modes or different frequencies are received through two independent signal receiving channels respectively; local oscillation frequency which is output to a frequency mixer by an voltage-controlled oscillator is regulated, so that radio frequency carrier frequency is mixed and an intermediate frequency signal is output; an intermediate frequency filter with image rejection is subjected to parameter configuration, so that an image rejection signal in the intermediate frequency signal matched with the intermediate frequency filter is rejected; and the frequency division value of a phase locked loop synthesizer with fractional-N frequency is configured so as to perform feedback control on the local oscillation frequency. By utilizing the method, sampling frequencies which are transmitted to two analog-digital converters by a digital phase locked loop are configured, and the sampling frequencies of the two analog-digital converters are same, so that the system and the interface design with an off-chip baseband processing chip of the system is simplified, and signal cross-talk is basically eliminated.

Description

technical field [0001] The invention relates to a communication chip and a frequency planning method thereof, in particular to a dual-channel radio frequency receiver suitable for global navigation system (GNSS) multi-frequency multi-mode reception and a frequency planning method thereof. Background technique [0002] GNSS (Global Navigation Satellite Systems) currently mainly includes the US Global Positioning System GPS (Global Positioning System), Russia's GLONASS Navigation Satellite System GLONASS (GLObal Navigation Satellite System), the European Union's Galileo Positioning System Galileo ( Galileo Positioning System) and China’s Beidou satellite navigation system Compass, see the corresponding frequency band division figure 1 The spectrum distribution diagram of GNSS navigation satellites is shown, and the corresponding encrypted P(Y) signals of GPS L1 and L2 are not drawn. [0003] From figure 1 It can be seen that the spectrum distribution of GNSS is about 1156MH...

AI Technical Summary

Problems solved by technology

[0009] First, due to the output clocks of the two digital-to-analog converters 109, that is figure 2 The output sampling frequency of the centerline 116 position is different, which leads to the complexity of the subsequent baseband processing chip;

[0010] Second, also due to the difference in the sampling frequencies output by the center line 116 of the upper and lower signal receiving channels, the corresponding high-order harmonics generated by each will inevitably be serially entered into its corresponding radio frequency channel through the signal input port of another channel , its amplitude can often completely annihilate the useful GNSS satellite signal, resulting in the failure of the RF receiver to receive

Images