Split-Band Data Conversion for Wideband Signal Sampling
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Solution Overview
Problem
Conventional data converters have limited measurement bandwidth and sensitivity, making it difficult to acquire signal samples over a wide frequency range extending from DC to greater than 10 Gigahertz, which is necessary for various instruments and systems.
Innovation Solution
A data conversion system comprising a signal splitter coupled with a low frequency silicon operational amplifier and a high frequency gallium arsenide amplifier, along with respective analog-to-digital converters, to create a frequency crossover network that minimizes insertion loss and provides a wide bandwidth and high dynamic range, enabling accurate amplification and sampling of signals across a broad frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional data converter uses a single amplifier and ADC, then the device complexity is low, but the measurement bandwidth and dynamic range are limited
Solution Approach 1:
The system divides the frequency spectrum into multiple bands using a polyphase filter bank, with each branch handling a specific frequency range. This segmentation allows each ADC to operate at lower rates while collectively covering a wide bandwidth, resolving the contradiction between measurement capability and device complexity.
Solution Approach 2:
The patent transforms the time-domain sampling problem into the frequency domain by using a polyphase filter bank. This dimensional transformation allows parallel processing of different frequency components, achieving wide bandwidth coverage without requiring a single high-speed ADC, thus managing device complexity while improving measurement capability.
2Measurement precision
If the data converter operates at high data conversion rates to cover wide bandwidth, then the measurement bandwidth is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The high data conversion rate requirement is segmented into multiple lower-rate ADCs, each handling a specific frequency band. This reduces the difficulty of detecting and measuring by distributing the sampling burden across multiple channels rather than requiring a single high-speed converter.
Solution Approach 2:
The patent replaces the mechanical approach of using a single high-speed ADC with an electrical signal processing approach using polyphase filtering and parallel ADCs. This substitution reduces the measurement difficulty by transforming the sampling problem into frequency-domain processing.
3Adaptability or versatility
If conventional data converters are used to achieve DC to 10 GHz frequency range, then the operating frequency range is limited, but the device complexity remains low
Solution Approach 1:
The frequency range from DC to 10 GHz is segmented into multiple bands, with each band processed by a dedicated filter branch and ADC. This segmentation enables the system to achieve wide frequency coverage while keeping each individual component operating within manageable parameters, balancing adaptability and device complexity.
Solution Approach 2:
The polyphase filter bank structure provides multi-functionality by simultaneously handling multiple frequency bands through a unified architecture. This universal approach allows the system to cover a wide operating frequency range without requiring entirely separate converter systems for each band, managing device complexity while improving adaptability.
Data Source
AI summary
A data conversion system acquires samples of low frequency signal components of an applied analog signal at a first data conversion rate and samples of high frequency signal components of the applied analog signal at a second data conversion rate that is higher than the first data conversion rate. The data conversion system applies a first correction filter to the acquired samples of the low frequency signal components to provide a first filtered signal and applies a second correction filter to the acquired samples of the high frequency signal components to provide a second filtered signal. The data conversion system interpolates the first filtered signal to provide an interpolated signal, and sums the interpolated signal with the second filtered signal to provide an output signal.