DC-Blocking Amplifier Circuit With Aliasing Tone Cancellation
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Solution Overview
Problem
Amplifiers with switched-capacitor feedback circuits generate aliasing tones due to clock signal mixing, affecting output signals by incorporating lower frequency components that existing solutions fail to adequately address.
Innovation Solution
Incorporation of aliasing tone cancellation circuits with storage blocks and frequency-selective or delay circuits to cancel or reduce the aliasing tones generated by switched-capacitor feedback, using capacitors and switches to alternate charge sharing and signal processing to mitigate the effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a switched-capacitor feedback circuit is used to provide high impedance for stabilizing operating points, then the operating point stability is improved, but aliasing tones are generated due to clock signal mixing
Solution Approach 1:
An aliasing tone cancellation circuit is introduced as an intermediary component between the switched-capacitor feedback circuit and the amplifier input. This cancellation circuit generates an anti-aliasing signal that counteracts the aliasing tone produced by the switched-capacitor feedback, effectively eliminating the harmful interference while preserving the high-impedance stabilization function
Solution Approach 2:
The aliasing tone cancellation circuit performs preliminary anti-action by generating a canceling signal before the aliasing tone affects the amplifier output. The cancellation circuit is designed to produce an signal that is equal in magnitude but opposite in phase to the expected aliasing tone, thereby neutralizing it before it can degrade the output signal quality
2Productivity
If the amplifier processes the aliasing tone, then the aliasing tone is amplified, but the output signal quality deteriorates
Solution Approach 1:
The aliasing tone cancellation circuit employs feedback mechanisms to continuously monitor and counteract aliasing tones. By sampling the output signal and generating a corresponding canceling signal that is fed back to the amplifier input, the system dynamically compensates for aliasing effects, preventing signal quality deterioration while maintaining full signal processing capability
Solution Approach 2:
The invention converts the harmful aliasing tone into a beneficial canceling signal. The aliasing tone generated by the switched-capacitor feedback is deliberately captured and processed to create an equal and opposite signal that, when combined with the original signal, eliminates the aliasing artifact and improves overall output quality
Data Source
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AI summary
The present invention provides an amplifier circuit, wherein the amplifier circuit includes an input terminal, a capacitor, an amplifier, a feedback circuit and an aliasing tone cancellation circuit. The input terminal is configured to receive a first input signal. The capacitor is coupled to the input terminal. The amplifier is configured to receive the input signal through the capacitor to generate an output signal. The feedback circuit is coupled between an input node and an output node of the amplifier, and is configured to generate a feedback signal according to the output signal, wherein the feedback circuit includes a storage block including a switched-capacitor. The aliasing tone cancellation circuit is coupled between the input terminal of the amplifier circuit and the input node of the amplifier, and configured to generate a signal to cancel or reduce an aliasing tone of the feedback signal according to the input signal.