Transformer-Coupled A/D Conversion for Low-Frequency Signal Precision
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Solution Overview
Problem
Conventional A/D conversion apparatuses face challenges in precisely converting low-frequency analog signals to digital signals without distortion, as they often suffer from contact degradation and slow signal switching due to mechanical relays, and the use of multiple converters increases costs and reduces precision due to inferior differential amplifier characteristics.
Innovation Solution
The apparatus employs a low bandpass filter, an up-converter, and a transformer to frequency-up-convert DC and low-frequency components, allowing for high-precision digital conversion using a semiconductor signal selection switch, which reduces distortion and contact issues, and shares gain blocks for both low and high frequencies, thereby reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical relays are used as signal selection switch to avoid distortion, then manufacturing precision is improved, but reliability deteriorates due to contact degradation and slow switching
Solution Approach 1:
The patent replaces mechanical relays with semiconductor switches (such as FETs or MOSFETs) in the signal selection switch 58. This substitution eliminates mechanical contact degradation while maintaining signal integrity through proper circuit design that prevents distortion in the semiconductor switch path.
2Adaptability or versatility
If multiple A/D converters are used for AC and DC coupled circuits, then adaptability is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the functionality of multiple A/D converters into a single A/D converter 60 by using a signal selection switch 58 that routes either the AC-coupled signal from transformer 53 or the DC-coupled signal from differential amplifier 57 to the same converter. This eliminates the need for separate A/D converters while maintaining wideband coverage including DC and low frequencies.
3Manufacturing precision
If transformer is used for AC coupled drive circuit, then manufacturing precision is improved for high frequencies, but adaptability deteriorates for DC and low frequency conversion
Solution Approach 1:
The patent segments the frequency handling into two paths: the transformer 53 handles AC-coupled high frequency signals with high precision, while the differential amplifier 57 handles DC and low frequency signals. A signal selection switch 58 routes the appropriate path based on frequency content, enabling the system to cover the full frequency range from DC to high frequencies with optimal precision in each segment.
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 high-precision conversion of wideband analog signals, including low frequencies, with improved durability and responsiveness, reducing manufacturing costs and maintaining high precision without distortion.
Implementation Method 1
a transformer receiving an input signal at a primary winding and providing an induced signal at a secondary winding
Data Source
AI summary
An up-converter 124 frequency-up-converts an analog signal Sm. A down-converter 121 frequency-down-converts analog signal Sm. A signal selection block 125 selects one of the frequency-up-converted signal Sfu and frequency-down-converted signal Sfd. The signal Se selected by the signal selection block 125 is provided to the primary winding of a transformer 127. A signal induced in the secondary winding of the transformer 127 is provided to an A/D converter 128 to produce a digital signal Dm. For example, if the analog signal Sm has DC or a low frequency close to DC, the signal Sfu is selected as the signal Se. If the analog signal Sm does no have DC nor a low frequency close to DC, the signal Sfd is selected as the signal Se.