Integrated IF Demodulator Filter Decimator for Lower-Rate Radio Reception
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Solution Overview
Problem
Superheterodyne radio receivers face challenges in handling high bandwidth signals due to the need for high sample rates, which can be costly and complex to achieve with existing hardware technologies, often requiring duplication of hardware to operate at half the rate, leading to increased power consumption and circuit area.
Innovation Solution
A method involving translating RF signals to an intermediate frequency, converting to digital samples at four times the IF, dividing samples into even and odd sets, and using parallel quadrature demodulators and filters to produce a baseband complex signal at half the sampling frequency, reducing processing and hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ADC sampling rate is increased to handle high bandwidth signals, then the signal bandwidth capability is improved, but the hardware cost, complexity, and power consumption increase
Solution Approach 1:
The patent divides the high-rate sampling process into multiple parallel lower-rate processes. Specifically, it segments the ADC sampling into multiple channels operating at reduced rates, processes them separately through demodulators and filters, then combines the results. This segmentation allows handling of high bandwidth signals without requiring a single high-speed hardware chain, thus reducing hardware complexity while maintaining signal bandwidth capability.
2Speed
If hardware is duplicated to operate at half the rate, then the processing rate requirement is reduced, but the circuit area and power consumption increase
Solution Approach 1:
The patent merges multiple processing functions (demodulation, filtering, and decimation) into an integrated architecture where parallel lower-rate processing paths are combined efficiently. Instead of duplicating full hardware chains, it combines multiple lower-rate processing paths that share common resources and are merged at the output stage, reducing the total circuit area compared to full duplication while achieving the desired processing rate reduction.
3Adaptability or versatility
If the ADC sampling rate is increased to handle high bandwidth signals, then the signal bandwidth capability is improved, but the power consumption increases
Solution Approach 1:
The patent segments the high-bandwidth signal processing into multiple parallel lower-rate processing paths. Each path operates at a reduced sampling rate, which directly reduces the power consumption of individual processing stages. The overall system achieves high bandwidth capability through parallel segmentation rather than through a single high-power path, thus maintaining signal bandwidth capability while reducing total power consumption.
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 reduces processing requirements, hardware cost, complexity, and power consumption while enabling the reception of high bandwidth signals without the undesirable tradeoffs of duplicated hardware, achieving significant savings in circuit area and operational efficiency.
Implementation Method 1
translating a received radio frequency (RF) signal to an intermediate frequency (IF) signal
Data Source
AI summary
A superheterodyne receiver includes an A/D converter for converting an IF signal to a stream of samples at a sampling frequency that is four times the IF and a splitter that splits the stream of samples into a first set of even samples and a second set of odd samples. A first quadrature demodulator demodulates just the first set of even samples to produce one of real (I) and imaginary (Q) components of a complex signal at one half of the sampling frequency, and a second, parallel quadrature demodulator demodulates just the second set of odd samples to produce the other of the I and Q components. The demodulated first set is filtered using a first subset of filter coefficients, and the demodulated second set is filtered using a second subset of filter coefficients. The filter outputs correspond to a baseband complex signal. The technology disclosed reduces overall hardware complexity and operating frequency by a factor of two or more.