Digital intermediate-frequency receiver

Abstract

The invention discloses a digital intermediate-frequency receiver. An analog intermediate-frequency signal of the frequency fAIF of any intermediate-frequency frequency point is input and is sampled by an A / D sampling module at sampling frequency fAD, a frequency point of a digital intermediate-frequency signal after bandpass sampling is fIF=mod(fAIF, fAD), the quadrature demodulation is performed through an NCO, the signal frequency is shift to a base band from the intermediate frequency, the digital intermediate-frequency receiver also comprises a first-stage filter, a sampling frequency conversion module, and a second-stage filter, the first-stage filter has a wider passband, partial high-frequency components in the signal after the shift are filtered to meet the anti-aliasing requirement of the sampling of the sampling frequency conversion module, the second-stage filter has a narrower passband, and the high-frequency components remained in the signal after the sampling frequency conversion are removed to improve adjacent channel selectivity. The digital intermediate-frequency receiver can be suitable for all the intermediate-frequency frequency points, and has low complexity and less consumption of hardware resources.

Description

technical field [0001] The invention belongs to the field of wireless signal transmission, in particular to a digital intermediate frequency receiver. Background technique [0002] In the process of receiving wireless signals, digital intermediate frequency data reception schemes are often adopted, that is, digital design methods are used to realize the conversion of signal frequency from intermediate frequency to baseband. Compared with the traditional analog IF receiving scheme, the digital IF receiving can generate quadrature signals with strict amplitude and phase balance, and the digital IF can also play the role of sampling rate conversion. [0003] Usually, the design of digital IF receiver depends on the IF frequency point f of the analog IF signal coming down from the RF tuner bandpass filter AIF , System effective signal bandwidth f BW , system sampling bandwidth f s and the spacing f between service carriers CI . where f BW ≤f s , f BW < f CI , f s wi...

AI Technical Summary

Problems solved by technology

[0005] However, in the initial stage of a standard promulgation, the frequency points of the IF signals output by various RF tuner manufacturers are inconsistent, and even do not have the characteristics of 4n±1 times the system sampling rate;

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