Subsampling Receiver With Off-Chip RF Band Pass Filter
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Solution Overview
Problem
Conventional wireless communication receivers face challenges in effectively filtering out-of-band signals while maintaining high selectivity for in-band signals, particularly in high-end applications requiring multiple band multiple mode and carrier aggregation, which complicates the design and increases power consumption and complexity.
Innovation Solution
A sub-sampling receiver architecture that includes an RF front end with secondary band pass-filtering, an analog-digital converter for sub-sampling and over-sampling, and digital signal processing to attenuate noise and interference, along with off-chip band pass filters like SAW or FBAR filters to enhance signal processing and reduce analog component complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an LC resonant circuit is used to amplify the wanted signal, then the signal amplification is achieved, but the quality factor is not good and it cannot effectively filter out-of-band signals
Solution Approach 1:
The filtering function is segmented from the integrated LC resonant circuit and implemented as a separate off-chip band pass filter. This segmentation allows the use of high-quality-factor off-chip filters while keeping the integrated circuit simple, effectively resolving the contradiction between signal amplification and out-of-band rejection.
Solution Approach 2:
An off-chip band pass filter is introduced as an intermediary component between the antenna and the integrated circuit. This intermediary provides high-selectivity filtering with high quality factor, enabling effective out-of-band signal rejection while maintaining signal amplification capabilities of the integrated circuit.
2Object-affected harmful factors
If a pre-filter with high selectivity is added to the front of the receiver, then out-of-band signal filtering is improved, but the device complexity and power consumption increase
Solution Approach 1:
The complex high-selectivity filtering function is extracted from the integrated circuit and implemented as a separate off-chip band pass filter. This extraction simplifies the integrated circuit design while maintaining high out-of-band rejection capability, effectively resolving the contradiction between filtering performance and device complexity.
Solution Approach 2:
The complex analog filtering mechanism integrated in the receiver is replaced by a simpler off-chip filter structure. This substitution maintains the high-selectivity filtering function while reducing the complexity of the integrated circuit and overall receiver structure.
3Device complexity
If conventional filtering methods are used, then simple circuit structure is maintained, but noise signals near the wanted signal cannot be effectively attenuated
Solution Approach 1:
The off-chip band pass filter performs preliminary filtering of out-of-band signals and noise before the signal enters the integrated circuit. This preliminary action removes harmful interference early in the signal path, allowing the simple integrated circuit to effectively process only the desired signal band.
Solution Approach 2:
High-quality filtering is applied locally at the critical input stage where out-of-band signals first enter the system. The off-chip band pass filter provides high-selectivity filtering precisely where it is most needed, while the rest of the integrated circuit maintains simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach simplifies the receiver structure, reduces power consumption, and enables efficient processing of wanted and unwanted signals near the wanted signal, supporting high-end applications like MIMO and CA with improved selectivity and reduced design complexity.
Implementation Method 1
an off-chip band pass filter of interstage type receiving an output of variable gain amplifier of the RF front-end portion to perform a direct anti-aliasing filtering, the off-chip band pass filter being embodied in a type of SAW filter or FBAR filter
Implementation Method 2
an off-chip band pass filter of interstage type receiving an output of variable gain amplifier of the RF front-end portion to perform a direct anti-aliasing filtering, the off-chip band pass filter being embodied in a type of SAW filter or FBAR filter
Implementation Method 3
an analog-digital converting portion that performs a sub-sampling on a carrier frequency of wanted signal band according to clock signals, performs an over sampling on a wanted signal band according to the clocks, converting an analog signal output from the RF front end portion into a digital signal
Data Source
AI summary
The inventive concept relates to a wireless communication receiver. The wireless communication receiver includes a second off-chip RF filter, an RF-to-digital converter and a digital pre-processor processing a signal converted into a digital. The RF-to-digital converter converts an RF signal being received into a digital signal of DC frequency band or intermediate frequency band and has a dynamic range that can process a wanted RF band signal and unwanted signals near to the wanted RF band signal. The digital pre-processor digitally controls a signal gain to transmit it to a modulator/demodulator.