Real-Time Spectrum Analyzer Polyphase Filter Bank

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Solution Overview

Problem

Conventional real-time spectrum analyzers face challenges in achieving high analysis bandwidths with minimal power consumption, as they require high sampling rates and large data volumes, leading to hardware limitations and reduced battery life in mobile devices, while existing solutions either compromise on real-time analysis or increase complexity.

Innovation Solution

The implementation of a receiver with a monolithic, integrated circuit that reduces time resolution by summing consecutive sampling values and using a numerically controlled oscillator to shift frequencies, allowing for time compression while maintaining full analysis bandwidth, along with a redundant signal path and CORDIC unit for enhanced time resolution and visualization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If high sampling rates are used to achieve high analysis bandwidth in real-time spectrum analyzers, then the analysis bandwidth is improved, but the data volume and power consumption increase dramatically

Engineering Contradiction:

Improveanalysis bandwidthVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent divides the frequency spectrum into multiple sub-bands using a polyphase filter bank structure. Each sub-band is processed independently with lower sampling rates, avoiding the need for a single high-rate ADC. This segmentation allows real-time analysis of large bandwidths while reducing the data volume and power consumption associated with high-speed sampling and processing.

Inventive Principle:

Principle #1Segmentation

2Reliability

If high sampling rates are used to maintain real-time analysis capability, then the real-time performance is improved, but the hardware complexity and processing requirements increase

Engineering Contradiction:

Improvereal-time analysis capabilityVSAvoidhardware complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the wide bandwidth into multiple narrower sub-bands that can be processed in parallel. Each sub-band processor operates at a manageable sampling rate, reducing individual hardware complexity while maintaining overall real-time performance through synchronized processing of all sub-bands.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines multiple low-rate ADCs and processing channels into a unified polyphase filter bank structure. This merging approach allows the system to achieve the functionality of a high-rate system while using multiple lower-rate components, thereby reducing hardware complexity and power consumption.

Inventive Principle:

Principle #5Merging (Combining)

3Use of energy by moving object

If the data volume is reduced downstream of the ADC to lower processing requirements, then the power consumption is reduced, but the measurement precision may be compromised

Engineering Contradiction:

Improvepower consumptionVSAvoidspectral analysis precision

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent performs preliminary filtering and frequency decomposition through the polyphase filter bank immediately after sampling. This preliminary action organizes the data into structured sub-bands before further processing, allowing efficient compression and processing while preserving spectral information. The structured approach ensures that no critical measurement information is lost during data reduction.

Inventive Principle:

Principle #10Preliminary action

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 enables real-time analysis of large bandwidths with minimal power consumption, ensuring that high-frequency signals are detected without compromising time resolution, and allows for visualization of spectra with minimal measurement errors and artifacts.

Implementation Method 1

using a numerically controlled oscillator to shift frequencies

Methodology Applied

Scientific EffectFrequency shifting:

Implementation Method 2

reduces time resolution by summing consecutive sampling values and using a numerically controlled oscillator to shift frequencies, allowing for time compression while maintaining full analysis bandwidth, along with a redundant signal path and CORDIC unit for enhanced time resolution

Methodology Applied

Scientific EffectCORDIC algorithm:

Data Source

PatentUS10914771B2Spectrum analyzer with increased real-time bandwidth

Publication Date: 2021.02.09 AARONIA

AI summary

Conventional real-time spectrum analyzers have a degree of technical complexity in the hardware which increases disproportionately as the analysis bandwidth increases for Fourier transformations of the measured sampling values. When using high analysis bandwidths, a detailed resolution is not needed of each analyzed individual frequency on the time plane at the same time; instead, detection of the presence of short pulses can be important as well. For this application, mixing sampling values on the time plane using a variable auxiliary frequency allows the sampling rate to be reduced, in that the bandwidth is maintained but a compression is carried out on the time plane. A very high time resolution which far exceeds the capabilities of conventional real-time spectrum analyzers can additionally be achieved overall for the analysis bandwidth, the time resolution then being computationally assignable to the individual frequencies for signal forms, in particular pulses, which occur in practice.